branch(main): Initial commit.

2026-09-12 08:25:10 -04:00 · 2026-09-12 08:25:10 -04:00 · ef72a56501
commit ef72a56501
142 changed files with 6977 additions and 0 deletions
--- a/.forgejo/workflows/publish.yml
+++ b/.forgejo/workflows/publish.yml
@ -0,0 +1,32 @@
+name: Build and publish
+
+on:
+  push:
+    branches: [main]
+    tags: ["v*"]
+  pull_request:
+
+jobs:
+  verify:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - uses: actions/setup-java@v4
+        with:
+          distribution: temurin
+          java-version: "25"
+      - run: ./gradlew test
+  publish:
+    if: startsWith(gitea.ref, 'refs/tags/v')
+    needs: verify
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - uses: actions/setup-java@v4
+        with:
+          distribution: temurin
+          java-version: "25"
+      - run: ./gradlew -Pversion="${GITHUB_REF_NAME#v}" publish
+        env:
+          ORG_GRADLE_PROJECT_forgejoUsername: ${{ secrets.FORGEJO_USERNAME }}
+          ORG_GRADLE_PROJECT_forgejoPassword: ${{ secrets.FORGEJO_TOKEN }}
--- a/.gitattributes
+++ b/.gitattributes
@ -0,0 +1,12 @@
+#
+# https://help.github.com/articles/dealing-with-line-endings/
+#
+# Linux start script should use lf
+/gradlew        text eol=lf
+
+# These are Windows script files and should use crlf
+*.bat           text eol=crlf
+
+# Binary files should be left untouched
+*.jar           binary
+
--- a/.gitignore
+++ b/.gitignore
@ -0,0 +1,8 @@
+# Ignore Gradle project-specific cache directory
+.gradle/
+
+# Ignore Gradle build output directory
+build/
+
+# Ignore Kotlin plugin data
+.kotlin/
--- a/README.md
+++ b/README.md
--- a/app/build.gradle.kts
+++ b/app/build.gradle.kts
@ -0,0 +1,3 @@
+dependencies {
+    testImplementation(kotlin("test"))
+}
--- a/app/src/main/kotlin/rip/crit/twist/App.kt
+++ b/app/src/main/kotlin/rip/crit/twist/App.kt
@ -0,0 +1,66 @@
+package rip.crit.twist
+
+import java.nio.file.Path
+import java.util.concurrent.CountDownLatch
+import rip.crit.twist.consensus.BasicConsensusEngine
+import rip.crit.twist.consensus.ConsensusEngine
+import rip.crit.twist.gossip.GossipService
+import rip.crit.twist.gossip.InMemoryGossipService
+import rip.crit.twist.p2p.PeerId
+import rip.crit.twist.p2p.PeerNetwork
+import rip.crit.twist.state.FileWorldState
+import rip.crit.twist.state.WorldState
+import rip.crit.twist.transport.TcpPeerNetwork
+
+class App(
+    val network: PeerNetwork,
+    val gossip: GossipService,
+    val consensus: ConsensusEngine,
+    val state: WorldState,
+) {
+    fun start() {
+        network.start()
+        gossip.start()
+        consensus.start()
+    }
+
+    fun stop() {
+        consensus.stop()
+        gossip.stop()
+        network.stop()
+    }
+}
+
+fun main(args: Array<String>) {
+    val root = Path.of(args.firstOrNull { !it.startsWith("--") } ?: "build/node")
+    val port = args.firstOrNull { it.startsWith("--port=") }?.substringAfter('=')?.toInt() ?: 0
+    val network = TcpPeerNetwork(PeerId("node-${root.fileName}"), port)
+    val app =
+        App(
+            network,
+            InMemoryGossipService(),
+            BasicConsensusEngine(),
+            FileWorldState(root.resolve("state")),
+        )
+    app.start()
+    args
+        .filter { it.startsWith("--peer=") }
+        .forEach { option ->
+            val (host, peerPort) = option.substringAfter('=').split(':', limit = 2)
+            network.connect(host, peerPort.toInt())
+        }
+    println("Twist node started data=$root port=${network.port}")
+    if ("--once" in args) {
+        app.stop()
+        return
+    }
+    val stopped = CountDownLatch(1)
+    Runtime.getRuntime()
+        .addShutdownHook(
+            Thread {
+                app.stop()
+                stopped.countDown()
+            }
+        )
+    stopped.await()
+}
--- a/app/src/main/kotlin/rip/crit/twist/access/AccessList.kt
+++ b/app/src/main/kotlin/rip/crit/twist/access/AccessList.kt
@ -0,0 +1,9 @@
+package rip.crit.twist.access
+
+import rip.crit.twist.core.Address
+
+data class AccessList(val reads: Set<Address> = emptySet(), val writes: Set<Address> = emptySet()) {
+    fun conflictsWith(other: AccessList): Boolean =
+        writes.intersect(other.reads + other.writes).isNotEmpty() ||
+            other.writes.intersect(reads).isNotEmpty()
+}
--- a/app/src/main/kotlin/rip/crit/twist/bips/FileStorageContract.kt
+++ b/app/src/main/kotlin/rip/crit/twist/bips/FileStorageContract.kt
@ -0,0 +1,35 @@
+package rip.crit.twist.bips
+
+import java.nio.file.Files
+import java.nio.file.Path
+import rip.crit.twist.core.Hash
+import rip.crit.twist.core.Sha256
+import rip.crit.twist.proof.ProofOfStore
+
+class FileStorageContract(private val root: Path) : StorageContract {
+    init {
+        Files.createDirectories(root)
+    }
+
+    override fun put(content: ByteArray): Hash {
+        val hash = Sha256.digest(content)
+        val target = pathFor(hash)
+        if (Files.notExists(target)) Files.write(target, content)
+        return hash
+    }
+
+    override fun get(pointer: Hash): ByteArray? {
+        val path = pathFor(pointer)
+        if (Files.notExists(path)) return null
+        val content = Files.readAllBytes(path)
+        return content.takeIf { Sha256.digest(it) == pointer }
+    }
+
+    fun prove(pointer: Hash, challenge: Hash): ProofOfStore? =
+        get(pointer)?.let { ProofOfStore.create(pointer, challenge) }
+
+    private fun pathFor(hash: Hash): Path {
+        require(hash.value.matches(Regex("[0-9a-f]{64}"))) { "Invalid content hash" }
+        return root.resolve(hash.value)
+    }
+}
--- a/app/src/main/kotlin/rip/crit/twist/bips/StorageContract.kt
+++ b/app/src/main/kotlin/rip/crit/twist/bips/StorageContract.kt
@ -0,0 +1,23 @@
+package rip.crit.twist.bips
+
+import rip.crit.twist.core.Hash
+
+interface StorageContract {
+    fun put(content: ByteArray): Hash
+
+    fun get(pointer: Hash): ByteArray?
+}
+
+class FolderStorageContract(private val storage: StorageContract) : StorageContract {
+    val mounts: MutableMap<String, Hash> = mutableMapOf()
+
+    override fun put(content: ByteArray): Hash {
+        val hash = storage.put(content)
+        mounts[hash.toString()] = hash
+        return hash
+    }
+
+    override fun get(pointer: Hash): ByteArray? {
+        return storage.get(pointer)
+    }
+}
--- a/app/src/main/kotlin/rip/crit/twist/burn/BurnPolicy.kt
+++ b/app/src/main/kotlin/rip/crit/twist/burn/BurnPolicy.kt
@ -0,0 +1,7 @@
+package rip.crit.twist.burn
+
+import rip.crit.twist.core.Amount
+
+fun interface BurnPolicy {
+    fun amountFor(fee: Amount): Amount
+}
--- a/app/src/main/kotlin/rip/crit/twist/burn/Policies.kt
+++ b/app/src/main/kotlin/rip/crit/twist/burn/Policies.kt
@ -0,0 +1,18 @@
+package rip.crit.twist.burn
+
+import java.math.BigInteger
+import rip.crit.twist.core.Amount
+
+class FractionalBurnPolicy(private val numerator: Long, private val denominator: Long) :
+    BurnPolicy {
+    init {
+        require(numerator in 0..denominator && denominator > 0)
+    }
+
+    override fun amountFor(fee: Amount): Amount =
+        Amount(
+            fee.value
+                .multiply(BigInteger.valueOf(numerator))
+                .divide(BigInteger.valueOf(denominator))
+        )
+}
--- a/app/src/main/kotlin/rip/crit/twist/bytecode/TwistBytecode.kt
+++ b/app/src/main/kotlin/rip/crit/twist/bytecode/TwistBytecode.kt
@ -0,0 +1,87 @@
+package rip.crit.twist.bytecode
+
+import java.nio.ByteBuffer
+
+enum class OpCode(val code: Byte) {
+    STOP(0),
+    PUSH32(1),
+    ADD(2),
+    SUB(3),
+    CALLDATA_LOAD(4),
+    TLOAD(5),
+    TSTORE(6),
+    RETURN(7),
+    MUL(8),
+    DIV(9),
+    EQ(10),
+    LT(11),
+    GT(12),
+    AND(13),
+    OR(14),
+    NOT(15),
+    JUMP(16),
+    JUMPI(17),
+    DUP(18),
+    SWAP(19),
+    LOG(20),
+    CALL(21),
+    CREATE(22),
+    SELFDESTRUCT(23),
+    REVERT(24),
+    SLOAD(25),
+    SSTORE(26),
+    CALLER(27),
+    CALLVALUE(28),
+    TIMESTAMP(29),
+    BLOCK_NUMBER(30),
+    BALANCE(31),
+    SHA256(32),
+    MOD(33),
+    XOR(34),
+    ISZERO(35),
+    POP(36),
+    SHL(37),
+    SHR(38),
+    BYTE(39),
+    MLOAD(40),
+    MSTORE(41),
+    MSIZE(42),
+    CALLDATA_SIZE(43),
+    CODE_SIZE(44),
+    GAS(45),
+    ADDRESS(46),
+    ORIGIN(47),
+    CHAIN_ID(48),
+    INVALID(0xFF.toByte()),
+}
+
+data class Instruction(val opCode: OpCode, val immediate: ByteArray = byteArrayOf()) {
+    init {
+        require(opCode != OpCode.PUSH32 || immediate.size == 32)
+    }
+}
+
+object TwistBytecode {
+    fun encode(instructions: List<Instruction>): ByteArray =
+        ByteBuffer.allocate(instructions.sumOf { 1 + it.immediate.size })
+            .also { output ->
+                instructions.forEach {
+                    output.put(it.opCode.code)
+                    output.put(it.immediate)
+                }
+            }
+            .array()
+
+    fun decode(code: ByteArray): List<Instruction> {
+        val input = ByteBuffer.wrap(code)
+        val output = mutableListOf<Instruction>()
+        while (input.hasRemaining()) {
+            val code = input.get()
+            val op = OpCode.entries.firstOrNull { it.code == code } ?: error("Unknown opcode")
+            val immediate =
+                if (op == OpCode.PUSH32) ByteArray(32).also(input::get) else byteArrayOf()
+            output += Instruction(op, immediate)
+        }
+        return output
+    }
+}
--- a/app/src/main/kotlin/rip/crit/twist/compiler/ContractIr.kt
+++ b/app/src/main/kotlin/rip/crit/twist/compiler/ContractIr.kt
@ -0,0 +1,100 @@
+package rip.crit.twist.compiler
+
+import java.math.BigInteger
+import rip.crit.twist.bytecode.Instruction
+import rip.crit.twist.bytecode.OpCode
+import rip.crit.twist.bytecode.TwistBytecode
+import rip.crit.twist.tvm.Word256
+
+enum class AccessOperation {
+    READ,
+    WRITE,
+    EXECUTE,
+}
+
+data class AccessRule(
+    val operation: AccessOperation,
+    val resource: String,
+    val principals: Set<String>,
+) {
+    init {
+        require(resource.isNotBlank())
+        require(principals.isNotEmpty())
+    }
+}
+
+data class IrAccessPolicy(val rules: List<AccessRule> = emptyList()) {
+    fun allows(principal: String, operation: AccessOperation, resource: String): Boolean =
+        rules.any {
+            it.operation == operation &&
+                (it.resource == resource || it.resource == "*") &&
+                (principal in it.principals || "*" in it.principals)
+        }
+
+    fun require(principal: String, operation: AccessOperation, resource: String) {
+        require(allows(principal, operation, resource)) {
+            "$principal lacks ${operation.name.lowercase()} access to $resource"
+        }
+    }
+}
+
+data class ContractIr(
+    val name: String,
+    val functions: List<FunctionIr>,
+    val accessPolicy: IrAccessPolicy = IrAccessPolicy(),
+) {
+    fun bytecode(): ByteArray = TwistBytecode.encode(functions.flatMap { it.instructions })
+}
+
+data class FunctionIr(val name: String, val selector: Int, val instructions: List<Instruction>)
+
+class ContractBuilder(private val name: String) {
+    private val functions = mutableListOf<FunctionIr>()
+    private val accessRules = mutableListOf<AccessRule>()
+
+    fun allow(operation: AccessOperation, resource: String, vararg principals: String) {
+        accessRules += AccessRule(operation, resource, principals.toSet())
+    }
+
+    fun function(name: String, selector: Int, body: FunctionBuilder.() -> Unit) {
+        require(functions.none { it.selector == selector }) { "Duplicate function selector" }
+        functions += FunctionIr(name, selector, FunctionBuilder().apply(body).build())
+    }
+
+    fun build(): ContractIr = ContractIr(name, functions.toList(), IrAccessPolicy(accessRules))
+}
+
+class FunctionBuilder {
+    private val instructions = mutableListOf<Instruction>()
+
+    fun push(value: BigInteger) = emit(OpCode.PUSH32, Word256.of(value).toBytes())
+
+    fun push(value: Long) = push(BigInteger.valueOf(value))
+
+    fun op(code: OpCode) = emit(code)
+
+    fun calldataLoad() = op(OpCode.CALLDATA_LOAD)
+
+    fun storageLoad() = op(OpCode.SLOAD)
+
+    fun storageStore() = op(OpCode.SSTORE)
+
+    fun caller() = op(OpCode.CALLER)
+
+    fun callValue() = op(OpCode.CALLVALUE)
+
+    fun emitLog() = op(OpCode.LOG)
+
+    fun returnWord() = op(OpCode.RETURN)
+
+    fun revert() = op(OpCode.REVERT)
+
+    internal fun build(): List<Instruction> = instructions.toList()
+
+    private fun emit(code: OpCode, immediate: ByteArray = byteArrayOf()) {
+        instructions += Instruction(code, immediate)
+    }
+}
+
+fun contract(name: String, body: ContractBuilder.() -> Unit): ContractIr =
+    ContractBuilder(name).apply(body).build()
--- a/app/src/main/kotlin/rip/crit/twist/compiler/LispIrCompiler.kt
+++ b/app/src/main/kotlin/rip/crit/twist/compiler/LispIrCompiler.kt
@ -0,0 +1,166 @@
+package rip.crit.twist.compiler
+
+import java.math.BigInteger
+import rip.crit.twist.bytecode.Instruction
+import rip.crit.twist.bytecode.OpCode
+import rip.crit.twist.tvm.Word256
+
+class LispIrCompiler {
+    fun parse(source: String): ContractIr {
+        val forms = Reader(source).readAll()
+        require(forms.size == 1) { "Expected one contract form" }
+        val contract = forms.single().list("contract")
+        require(contract.size >= 2)
+        val name = contract[1].atom()
+        val rules = mutableListOf<AccessRule>()
+        val functions = mutableListOf<FunctionIr>()
+        contract.drop(2).forEach { form ->
+            val values = form.list()
+            when (values.firstOrNull()?.atom()) {
+                "access" -> rules += parseAccess(values.drop(1))
+                "function" -> functions += parseFunction(values)
+                else -> error("Unknown contract form ${values.firstOrNull()}")
+            }
+        }
+        require(functions.map { it.selector }.distinct().size == functions.size) {
+            "Duplicate function selector"
+        }
+        return ContractIr(name, functions, IrAccessPolicy(rules))
+    }
+
+    fun compile(source: String, principal: String): ByteArray {
+        val ir = parse(source)
+        ir.functions.forEach { function ->
+            ir.accessPolicy.require(principal, AccessOperation.EXECUTE, "function:${function.name}")
+            function.instructions.forEach { instruction ->
+                when (instruction.opCode) {
+                    OpCode.SLOAD ->
+                        ir.accessPolicy.require(principal, AccessOperation.READ, "storage:*")
+
+                    OpCode.SSTORE ->
+                        ir.accessPolicy.require(principal, AccessOperation.WRITE, "storage:*")
+
+                    else -> Unit
+                }
+            }
+        }
+        return ir.bytecode()
+    }
+
+    private fun parseAccess(forms: List<SExpr>): List<AccessRule> = forms.map { form ->
+        val values = form.list()
+        require(values.size >= 3) { "Access rule needs an operation, resource, and principal" }
+        AccessRule(
+            AccessOperation.valueOf(values[0].atom().uppercase()),
+            values[1].atom(),
+            values.drop(2).map(SExpr::atom).toSet(),
+        )
+    }
+
+    private fun parseFunction(values: List<SExpr>): FunctionIr {
+        require(values.size >= 4) { "Function needs a name, selector, and body" }
+        val instructions = values.drop(3).map(::instruction)
+        return FunctionIr(values[1].atom(), values[2].atom().toInt(), instructions)
+    }
+
+    private fun instruction(form: SExpr): Instruction {
+        val values = form.list()
+        val name = values.first().atom().replace('-', '_').uppercase()
+        val opcode = OpCode.entries.firstOrNull { it.name == name } ?: error("Unknown IR op $name")
+        return if (opcode == OpCode.PUSH32) {
+            require(values.size == 2) { "push32 needs one integer" }
+            Instruction(opcode, Word256.of(BigInteger(values[1].atom())).toBytes())
+        } else {
+            require(values.size == 1) { "$name takes no operands" }
+            Instruction(opcode)
+        }
+    }
+}
+
+private sealed interface SExpr {
+    data class Atom(val value: String) : SExpr
+
+    data class Form(val values: List<SExpr>) : SExpr
+
+    fun atom(): String = (this as? Atom)?.value ?: error("Expected atom")
+
+    fun list(expectedHead: String? = null): List<SExpr> =
+        (this as? Form)?.values?.also {
+            if (expectedHead != null)
+                require(it.firstOrNull()?.atom() == expectedHead) { "Expected $expectedHead form" }
+        } ?: error("Expected list")
+}
+
+private class Reader(source: String) {
+    private val tokens = tokenize(source)
+    private var position = 0
+
+    fun readAll(): List<SExpr> = buildList { while (position < tokens.size) add(read()) }
+
+    private fun read(): SExpr {
+        require(position < tokens.size) { "Unexpected end of input" }
+        return when (val token = tokens[position++]) {
+            "(" -> {
+                val children = mutableListOf<SExpr>()
+                while (tokens.getOrNull(position) != ")") children += read()
+                require(position < tokens.size) { "Unclosed list" }
+                position++
+                SExpr.Form(children)
+            }
+
+            ")" -> error("Unexpected closing parenthesis")
+            else -> SExpr.Atom(token)
+        }
+    }
+
+    private companion object {
+        fun tokenize(source: String): List<String> {
+            val output = mutableListOf<String>()
+            var index = 0
+            while (index < source.length) {
+                when {
+                    source[index].isWhitespace() -> index++
+                    source[index] == ';' -> {
+                        while (index < source.length && source[index] != '\n') index++
+                    }
+
+                    source[index] == '(' || source[index] == ')' ->
+                        output.add(source[index++].toString())
+
+                    source[index] == '"' -> {
+                        index++
+                        val value = StringBuilder()
+                        while (index < source.length && source[index] != '"') {
+                            if (source[index] == '\\') {
+                                index++
+                                require(index < source.length)
+                                value.append(
+                                    when (source[index]) {
+                                        'n' -> '\n'
+                                        't' -> '\t'
+                                        else -> source[index]
+                                    }
+                                )
+                            } else value.append(source[index])
+                            index++
+                        }
+                        require(index < source.length) { "Unclosed string" }
+                        index++
+                        output += value.toString()
+                    }
+
+                    else -> {
+                        val start = index
+                        while (
+                            index < source.length &&
+                                !source[index].isWhitespace() &&
+                                source[index] !in "();"
+                        ) index++
+                        output += source.substring(start, index).removePrefix(":")
+                    }
+                }
+            }
+            return output
+        }
+    }
+}
--- a/app/src/main/kotlin/rip/crit/twist/compiler/TwistCompiler.kt
+++ b/app/src/main/kotlin/rip/crit/twist/compiler/TwistCompiler.kt
@ -0,0 +1,43 @@
+package rip.crit.twist.compiler
+
+import rip.crit.twist.bytecode.Instruction
+import rip.crit.twist.bytecode.OpCode
+import rip.crit.twist.bytecode.TwistBytecode
+import rip.crit.twist.jit.LLVMBuilder
+import rip.crit.twist.tvm.Word256
+
+object ContractPrelude {
+    const val SOURCE =
+        "(pragma twist \"1.0\")\n;; calldata is read with CALLDATA_LOAD and temporary state with TLOAD/TSTORE"
+}
+
+class TwistCompiler {
+    fun compile(source: String): ByteArray =
+        TwistBytecode.encode(source.lineSequence().mapNotNull(::instruction).toList())
+
+    fun lowerToLlvm(source: String, moduleName: String = "contract"): LLVMBuilder =
+        LLVMBuilder(moduleName, ContractPrelude.SOURCE + "\n" + source)
+
+    private fun instruction(line: String): Instruction? {
+        val tokens = line.trim().split(Regex("\\s+"))
+        if (tokens.isEmpty() || tokens[0].isBlank() || tokens[0].startsWith(";")) return null
+        return when (tokens[0].uppercase()) {
+            "PUSH32" ->
+                Instruction(
+                    OpCode.PUSH32,
+                    Word256.of(
+                            java.math.BigInteger(
+                                tokens.getOrElse(1) { error("PUSH32 needs a value") }
+                            )
+                        )
+                        .toBytes(),
+                )
+
+            else ->
+                Instruction(
+                    OpCode.entries.firstOrNull { it.name == tokens[0].uppercase() }
+                        ?: error("Unknown instruction ${tokens[0]}")
+                )
+        }
+    }
+}
--- a/app/src/main/kotlin/rip/crit/twist/consensus/BasicConsensusEngine.kt
+++ b/app/src/main/kotlin/rip/crit/twist/consensus/BasicConsensusEngine.kt
@ -0,0 +1,36 @@
+package rip.crit.twist.consensus
+
+import rip.crit.twist.core.Block
+import rip.crit.twist.core.Hash
+
+/** Structural consensus gate. Signature and committee policies compose above this layer. */
+class BasicConsensusEngine(private val genesisParent: Hash = Hash("genesis")) : ConsensusEngine {
+    private var running = false
+    private var tipHeight = -1L
+    private var tipHash: Hash? = null
+
+    override fun start() {
+        running = true
+    }
+
+    override fun stop() {
+        running = false
+    }
+
+    override fun validate(block: Block): ValidationResult =
+        synchronized(this) {
+            if (!running) return ValidationResult(false, "Consensus engine is stopped")
+            if (block.header.height < 0 || block.header.timestampMillis < 0)
+                return ValidationResult(false, "Invalid header")
+            if (tipHash == null && block.header.parentHash != genesisParent)
+                return ValidationResult(false, "Invalid genesis parent")
+            if (
+                tipHash != null &&
+                    (block.header.parentHash != tipHash || block.header.height != tipHeight + 1)
+            )
+                return ValidationResult(false, "Block does not extend canonical tip")
+            tipHash = block.hash
+            tipHeight = block.header.height
+            ValidationResult(true)
+        }
+}
--- a/app/src/main/kotlin/rip/crit/twist/consensus/ConsensusEngine.kt
+++ b/app/src/main/kotlin/rip/crit/twist/consensus/ConsensusEngine.kt
@ -0,0 +1,13 @@
+package rip.crit.twist.consensus
+
+import rip.crit.twist.core.Block
+
+interface ConsensusEngine {
+    fun start()
+
+    fun stop()
+
+    fun validate(block: Block): ValidationResult
+}
+
+data class ValidationResult(val accepted: Boolean, val reason: String? = null)
--- a/app/src/main/kotlin/rip/crit/twist/core/HmacSha256.kt
+++ b/app/src/main/kotlin/rip/crit/twist/core/HmacSha256.kt
@ -0,0 +1,10 @@
+package rip.crit.twist.core
+
+object HmacSha256 {
+    fun digest(key: ByteArray, message: ByteArray): ByteArray {
+        val normalized = (if (key.size > 64) Sha256.bytes(key) else key).copyOf(64)
+        val inner = ByteArray(64) { (normalized[it].toInt() xor 0x36).toByte() }
+        val outer = ByteArray(64) { (normalized[it].toInt() xor 0x5c).toByte() }
+        return Sha256.bytes(outer + Sha256.bytes(inner + message))
+    }
+}
--- a/app/src/main/kotlin/rip/crit/twist/core/Sha256.kt
+++ b/app/src/main/kotlin/rip/crit/twist/core/Sha256.kt
@ -0,0 +1,170 @@
+package rip.crit.twist.core
+
+@SmartDoc(
+    summary = "Pure Kotlin SHA-256 digest API.",
+    category = "Cryptography",
+    stability = "stable",
+)
+object Sha256 {
+    fun bytes(bytes: ByteArray): ByteArray = Sha256Digest.digest(bytes)
+
+    fun digest(bytes: ByteArray): Hash = Hash(bytes(bytes).toHex())
+
+    fun digestUtf8(value: String): Hash = digest(value.encodeToByteArray())
+
+    fun combine(left: Hash, right: Hash): Hash =
+        digest((left.value + right.value).encodeToByteArray())
+
+    private fun ByteArray.toHex(): String = joinToString("") { "%02x".format(it) }
+}
+
+/** Straightforward FIPS 180-4 SHA-256. Written for clarity, not side-channel resistance. */
+object Sha256Digest {
+    private val initial =
+        intArrayOf(
+            0x6a09e667,
+            0xbb67ae85.toInt(),
+            0x3c6ef372,
+            0xa54ff53a.toInt(),
+            0x510e527f,
+            0x9b05688c.toInt(),
+            0x1f83d9ab,
+            0x5be0cd19,
+        )
+    private val constants =
+        intArrayOf(
+            0x428a2f98,
+            0x71374491,
+            0xb5c0fbcf.toInt(),
+            0xe9b5dba5.toInt(),
+            0x3956c25b,
+            0x59f111f1,
+            0x923f82a4.toInt(),
+            0xab1c5ed5.toInt(),
+            0xd807aa98.toInt(),
+            0x12835b01,
+            0x243185be,
+            0x550c7dc3,
+            0x72be5d74,
+            0x80deb1fe.toInt(),
+            0x9bdc06a7.toInt(),
+            0xc19bf174.toInt(),
+            0xe49b69c1.toInt(),
+            0xefbe4786.toInt(),
+            0x0fc19dc6,
+            0x240ca1cc,
+            0x2de92c6f,
+            0x4a7484aa,
+            0x5cb0a9dc,
+            0x76f988da,
+            0x983e5152.toInt(),
+            0xa831c66d.toInt(),
+            0xb00327c8.toInt(),
+            0xbf597fc7.toInt(),
+            0xc6e00bf3.toInt(),
+            0xd5a79147.toInt(),
+            0x06ca6351,
+            0x14292967,
+            0x27b70a85,
+            0x2e1b2138,
+            0x4d2c6dfc,
+            0x53380d13,
+            0x650a7354,
+            0x766a0abb,
+            0x81c2c92e.toInt(),
+            0x92722c85.toInt(),
+            0xa2bfe8a1.toInt(),
+            0xa81a664b.toInt(),
+            0xc24b8b70.toInt(),
+            0xc76c51a3.toInt(),
+            0xd192e819.toInt(),
+            0xd6990624.toInt(),
+            0xf40e3585.toInt(),
+            0x106aa070,
+            0x19a4c116,
+            0x1e376c08,
+            0x2748774c,
+            0x34b0bcb5,
+            0x391c0cb3,
+            0x4ed8aa4a,
+            0x5b9cca4f,
+            0x682e6ff3,
+            0x748f82ee,
+            0x78a5636f,
+            0x84c87814.toInt(),
+            0x8cc70208.toInt(),
+            0x90befffa.toInt(),
+            0xa4506ceb.toInt(),
+            0xbef9a3f7.toInt(),
+            0xc67178f2.toInt(),
+        )
+
+    fun digest(message: ByteArray): ByteArray {
+        val bitLength = message.size.toLong() * 8
+        val padding = (56 - (message.size + 1) % 64 + 64) % 64
+        val input = ByteArray(message.size + 1 + padding + 8)
+        message.copyInto(input)
+        input[message.size] = 0x80.toByte()
+        for (i in 0..7) input[input.lastIndex - i] = (bitLength ushr (8 * i)).toByte()
+        val hash = initial.copyOf()
+        val words = IntArray(64)
+        for (offset in input.indices step 64) {
+            for (i in 0 until 16) {
+                val p = offset + i * 4
+                words[i] =
+                    ((input[p].toInt() and 0xff) shl 24) or
+                        ((input[p + 1].toInt() and 0xff) shl 16) or
+                        ((input[p + 2].toInt() and 0xff) shl 8) or
+                        (input[p + 3].toInt() and 0xff)
+            }
+            for (i in 16 until 64) {
+                val s0 =
+                    words[i - 15].rotateRight(7) xor
+                        words[i - 15].rotateRight(18) xor
+                        (words[i - 15] ushr 3)
+                val s1 =
+                    words[i - 2].rotateRight(17) xor
+                        words[i - 2].rotateRight(19) xor
+                        (words[i - 2] ushr 10)
+                words[i] = words[i - 16] + s0 + words[i - 7] + s1
+            }
+            var a = hash[0]
+            var b = hash[1]
+            var c = hash[2]
+            var d = hash[3]
+            var e = hash[4]
+            var f = hash[5]
+            var g = hash[6]
+            var h = hash[7]
+            for (i in 0 until 64) {
+                val sum1 = e.rotateRight(6) xor e.rotateRight(11) xor e.rotateRight(25)
+                val choice = (e and f) xor (e.inv() and g)
+                val temporary1 = h + sum1 + choice + constants[i] + words[i]
+                val sum0 = a.rotateRight(2) xor a.rotateRight(13) xor a.rotateRight(22)
+                val majority = (a and b) xor (a and c) xor (b and c)
+                val temporary2 = sum0 + majority
+                h = g
+                g = f
+                f = e
+                e = d + temporary1
+                d = c
+                c = b
+                b = a
+                a = temporary1 + temporary2
+            }
+            hash[0] += a
+            hash[1] += b
+            hash[2] += c
+            hash[3] += d
+            hash[4] += e
+            hash[5] += f
+            hash[6] += g
+            hash[7] += h
+        }
+        return ByteArray(32).also { output ->
+            hash.forEachIndexed { i, value ->
+                for (j in 0..3) output[i * 4 + j] = (value ushr (24 - j * 8)).toByte()
+            }
+        }
+    }
+}
--- a/app/src/main/kotlin/rip/crit/twist/core/SmartDoc.kt
+++ b/app/src/main/kotlin/rip/crit/twist/core/SmartDoc.kt
@ -0,0 +1,10 @@
+package rip.crit.twist.core
+
+/** Marks a public API for inclusion in generated SmartDoc reference pages. */
+@Target(AnnotationTarget.CLASS, AnnotationTarget.FUNCTION, AnnotationTarget.PROPERTY)
+@Retention(AnnotationRetention.SOURCE)
+annotation class SmartDoc(
+    val summary: String,
+    val category: String,
+    val stability: String = "experimental",
+)
--- a/app/src/main/kotlin/rip/crit/twist/core/TransactionHasher.kt
+++ b/app/src/main/kotlin/rip/crit/twist/core/TransactionHasher.kt
@ -0,0 +1,56 @@
+package rip.crit.twist.core
+
+import java.nio.ByteBuffer
+
+object TransactionHasher {
+    fun hash(
+        sender: Address,
+        recipient: Address?,
+        nonce: Long,
+        value: Amount,
+        payload: ByteArray,
+    ): Hash {
+        val recipientBytes = recipient?.value?.encodeToByteArray() ?: byteArrayOf()
+        val senderBytes = sender.value.encodeToByteArray()
+        val valueBytes = value.value.toByteArray()
+        val buffer =
+            ByteBuffer.allocate(
+                8 +
+                    4 +
+                    senderBytes.size +
+                    4 +
+                    recipientBytes.size +
+                    4 +
+                    valueBytes.size +
+                    4 +
+                    payload.size
+            )
+        buffer.putLong(nonce)
+        buffer.putSized(senderBytes)
+        buffer.putSized(recipientBytes)
+        buffer.putSized(valueBytes)
+        buffer.putSized(payload)
+        return Sha256.digest(buffer.array())
+    }
+
+    fun create(
+        sender: Address,
+        recipient: Address?,
+        nonce: Long,
+        value: Amount,
+        payload: ByteArray = byteArrayOf(),
+    ): Transaction =
+        Transaction(
+            hash(sender, recipient, nonce, value, payload),
+            sender,
+            recipient,
+            nonce,
+            value,
+            payload.copyOf(),
+        )
+
+    private fun ByteBuffer.putSized(value: ByteArray) {
+        putInt(value.size)
+        put(value)
+    }
+}
--- a/app/src/main/kotlin/rip/crit/twist/core/TwistSpecific.kt
+++ b/app/src/main/kotlin/rip/crit/twist/core/TwistSpecific.kt
@ -0,0 +1,6 @@
+package rip.crit.twist.core
+
+/** Explicit capability required to enable Twist-only, non-standard protocols. */
+sealed class TwistSpecific private constructor() {
+    data object Enabled : TwistSpecific()
+}
--- a/app/src/main/kotlin/rip/crit/twist/core/Types.kt
+++ b/app/src/main/kotlin/rip/crit/twist/core/Types.kt
@ -0,0 +1,71 @@
+package rip.crit.twist.core
+
+import java.math.BigInteger
+
+@JvmInline
+value class Address(val value: String) {
+    init {
+        require(value.isNotBlank())
+    }
+}
+
+@JvmInline
+value class Hash(val value: String) {
+    init {
+        require(value.isNotBlank())
+    }
+    companion object {
+        val ZERO = Hash("00000000000000000000000000000000")
+    }
+}
+
+@JvmInline
+value class Amount(val value: BigInteger) {
+    init {
+        require(value >= BigInteger.ZERO)
+    }
+}
+
+data class Transaction(
+    val id: Hash,
+    val sender: Address,
+    val recipient: Address?,
+    val nonce: Long,
+    val value: Amount,
+    val payload: ByteArray = byteArrayOf(),
+) {
+    override fun equals(other: Any?): Boolean {
+        if (this === other) return true
+        if (javaClass != other?.javaClass) return false
+
+        other as Transaction
+
+        if (nonce != other.nonce) return false
+        if (id != other.id) return false
+        if (sender != other.sender) return false
+        if (recipient != other.recipient) return false
+        if (value != other.value) return false
+        if (!payload.contentEquals(other.payload)) return false
+
+        return true
+    }
+
+    override fun hashCode(): Int {
+        var result = nonce.hashCode()
+        result = 31 * result + id.hashCode()
+        result = 31 * result + sender.hashCode()
+        result = 31 * result + recipient.hashCode()
+        result = 31 * result + value.hashCode()
+        result = 31 * result + payload.contentHashCode()
+        return result
+    }
+}
+
+data class BlockHeader(
+    val parentHash: Hash,
+    val stateRoot: Hash,
+    val height: Long,
+    val timestampMillis: Long,
+)
+
+data class Block(val header: BlockHeader, val transactions: List<Transaction>, val hash: Hash)
--- a/app/src/main/kotlin/rip/crit/twist/did/Did.kt
+++ b/app/src/main/kotlin/rip/crit/twist/did/Did.kt
@ -0,0 +1,201 @@
+package rip.crit.twist.did
+
+import java.math.BigInteger
+import java.time.Clock
+import java.time.Duration
+import rip.crit.twist.core.Hash
+import rip.crit.twist.core.Sha256
+import rip.crit.twist.core.SmartDoc
+import rip.crit.twist.core.TwistSpecific
+import rip.crit.twist.p2p.DistributedHashTable
+import rip.crit.twist.p2p.PeerId
+import rip.crit.twist.p2p.PeerRecord
+import rip.crit.twist.store.KeyValueStore
+
+@JvmInline
+value class Did(val value: String) {
+    init {
+        require(value.matches(Regex("did:[a-z0-9]+:[A-Za-z0-9._:%-]+"))) { "Invalid DID" }
+    }
+
+    val method: String
+        get() = value.substringAfter("did:").substringBefore(':')
+
+    val methodSpecificId: String
+        get() = value.substringAfter("did:$method:")
+}
+
+data class VerificationMethod(
+    val id: String,
+    val type: String,
+    val controller: Did,
+    val publicKeyMultibase: String,
+)
+
+data class DidService(val id: String, val type: String, val endpoint: String)
+
+data class DidDocument(
+    val id: Did,
+    val verificationMethods: List<VerificationMethod>,
+    val authentication: List<String> = verificationMethods.map { it.id },
+    val assertionMethod: List<String> = verificationMethods.map { it.id },
+    val services: List<DidService> = emptyList(),
+) {
+    fun toJson(): String = buildString {
+        append("{\"@context\":[\"https://www.w3.org/ns/did/v1.1\"],\"id\":\"")
+        append(id.value.escape())
+        append("\",\"verificationMethod\":[")
+        append(
+            verificationMethods.joinToString(",") {
+                "{\"id\":\"${it.id.escape()}\",\"type\":\"${it.type.escape()}\"," +
+                    "\"controller\":\"${it.controller.value.escape()}\"," +
+                    "\"publicKeyMultibase\":\"${it.publicKeyMultibase.escape()}\"}"
+            }
+        )
+        append("],\"authentication\":${strings(authentication)}")
+        append(",\"assertionMethod\":${strings(assertionMethod)}")
+        append(
+            ",\"service\":[${services.joinToString(",") { "{\"id\":\"${it.id.escape()}\",\"type\":\"${it.type.escape()}\",\"serviceEndpoint\":\"${it.endpoint.escape()}\"}" }}]"
+        )
+        append('}')
+    }
+
+    private fun strings(values: List<String>) =
+        values.joinToString(",", "[", "]") { "\"${it.escape()}\"" }
+
+    private fun String.escape() = replace("\\", "\\\\").replace("\"", "\\\"").replace("\n", "\\n")
+}
+
+enum class KeyCodec(val multicodec: Int) {
+    X25519(0xec),
+    ED25519(0xed),
+    SECP256K1(0xe7),
+}
+
+@SmartDoc(summary = "Generative did:key identifiers and DID documents.", category = "Identity")
+object DidKey {
+    fun create(publicKey: ByteArray, codec: KeyCodec): Did {
+        require(publicKey.isNotEmpty())
+        return Did("did:key:z${Base58.encode(varint(codec.multicodec) + publicKey)}")
+    }
+
+    fun resolve(did: Did): DidDocument {
+        require(did.method == "key")
+        val multibase = did.methodSpecificId
+        require(multibase.startsWith('z')) { "Only base58-btc did:key values are supported" }
+        val decoded = Base58.decode(multibase.drop(1))
+        val (codec, prefixSize) = readVarint(decoded)
+        require(KeyCodec.entries.any { it.multicodec == codec }) { "Unsupported key multicodec" }
+        require(decoded.size > prefixSize) { "Missing public key" }
+        val keyId = "${did.value}#$multibase"
+        return DidDocument(
+            did,
+            listOf(VerificationMethod(keyId, "Multikey", did, multibase)),
+        )
+    }
+
+    private fun varint(value: Int): ByteArray {
+        var remaining = value
+        val bytes = mutableListOf<Byte>()
+        do {
+            var next = remaining and 0x7f
+            remaining = remaining ushr 7
+            if (remaining != 0) next = next or 0x80
+            bytes += next.toByte()
+        } while (remaining != 0)
+        return bytes.toByteArray()
+    }
+
+    private fun readVarint(bytes: ByteArray): Pair<Int, Int> {
+        var value = 0
+        var shift = 0
+        for (index in 0 until minOf(bytes.size, 5)) {
+            val current = bytes[index].toInt() and 0xff
+            value = value or ((current and 0x7f) shl shift)
+            if (current and 0x80 == 0) return value to index + 1
+            shift += 7
+        }
+        error("Invalid multicodec varint")
+    }
+}
+
+/** Project-specific DID method resolved through the Twist peer DHT. */
+@SmartDoc(summary = "DHT-backed project-specific did:twist resolver.", category = "Identity")
+class DidTwist(
+    @Suppress("UNUSED_PARAMETER") twistSpecific: TwistSpecific.Enabled,
+    private val dht: DistributedHashTable,
+    private val documents: KeyValueStore,
+    private val clock: Clock = Clock.systemUTC(),
+) {
+    fun create(
+        peer: PeerId,
+        publicKey: ByteArray,
+        endpoints: Set<String>,
+        ttl: Duration,
+        codec: KeyCodec = KeyCodec.X25519,
+    ): Did {
+        require(endpoints.isNotEmpty())
+        val fingerprint = Sha256.digest(peer.value.encodeToByteArray() + publicKey).value
+        val did = Did("did:twist:$fingerprint")
+        dht.put(key(did), PeerRecord(peer, endpoints, clock.instant().plus(ttl)))
+        documents.put(
+            did.value.encodeToByteArray(),
+            byteArrayOf(codec.ordinal.toByte()) + publicKey,
+        )
+        return did
+    }
+
+    fun resolve(did: Did): DidDocument? {
+        require(did.method == "twist")
+        val record = dht.get(key(did)) ?: return null
+        val stored = documents.get(did.value.encodeToByteArray()) ?: return null
+        if (stored.size < 2) return null
+        val codec = KeyCodec.entries.getOrNull(stored[0].toInt()) ?: return null
+        val multibase = DidKey.create(stored.copyOfRange(1, stored.size), codec).methodSpecificId
+        val keyId = "${did.value}#$multibase"
+        return DidDocument(
+            did,
+            listOf(VerificationMethod(keyId, "Multikey", did, multibase)),
+            listOf(keyId),
+            listOf(keyId),
+            record.addresses.sorted().mapIndexed { index, endpoint ->
+                DidService("${did.value}#overlay-$index", "TwistOverlay", endpoint)
+            },
+        )
+    }
+
+    private fun key(did: Did): Hash = Sha256.digestUtf8(did.value)
+}
+
+internal object Base58 {
+    private const val ALPHABET = "123456789ABCDEFGHJKLMNPQRSTUVWXYZabcdefghijkmnopqrstuvwxyz"
+
+    fun encode(bytes: ByteArray): String {
+        if (bytes.isEmpty()) return ""
+        var value = BigInteger(1, bytes)
+        val output = StringBuilder()
+        val radix = BigInteger.valueOf(58)
+        while (value.signum() > 0) {
+            val parts = value.divideAndRemainder(radix)
+            output.append(ALPHABET[parts[1].toInt()])
+            value = parts[0]
+        }
+        bytes.takeWhile { it == 0.toByte() }.forEach { _ -> output.append('1') }
+        return output.reverse().toString()
+    }
+
+    fun decode(value: String): ByteArray {
+        require(value.isNotEmpty())
+        var number = BigInteger.ZERO
+        value.forEach { character ->
+            val digit = ALPHABET.indexOf(character)
+            require(digit >= 0) { "Invalid base58-btc character" }
+            number = number * BigInteger.valueOf(58) + BigInteger.valueOf(digit.toLong())
+        }
+        val raw =
+            number.toByteArray().let {
+                if (it.size > 1 && it[0] == 0.toByte()) it.drop(1).toByteArray() else it
+            }
+        return ByteArray(value.takeWhile { it == '1' }.length) + raw
+    }
+}
--- a/app/src/main/kotlin/rip/crit/twist/did/DidMethodRegistry.kt
+++ b/app/src/main/kotlin/rip/crit/twist/did/DidMethodRegistry.kt
@ -0,0 +1,25 @@
+package rip.crit.twist.did
+
+import rip.crit.twist.core.TwistSpecific
+
+fun interface DidResolver {
+    fun resolve(did: Did): DidDocument?
+}
+
+class DidMethodRegistry private constructor(private val resolvers: Map<String, DidResolver>) {
+    fun resolve(did: Did): DidDocument? = resolvers[did.method]?.resolve(did)
+
+    companion object {
+        fun create(
+            twistSpecific: TwistSpecific? = null,
+            twist: DidTwist? = null,
+        ): DidMethodRegistry {
+            require(twist == null || twistSpecific === TwistSpecific.Enabled) {
+                "did:twist registration requires TwistSpecific.Enabled"
+            }
+            val methods = mutableMapOf<String, DidResolver>("key" to DidResolver(DidKey::resolve))
+            if (twist != null) methods["twist"] = DidResolver(twist::resolve)
+            return DidMethodRegistry(methods)
+        }
+    }
+}
--- a/app/src/main/kotlin/rip/crit/twist/ecdsa/Ecdsa.kt
+++ b/app/src/main/kotlin/rip/crit/twist/ecdsa/Ecdsa.kt
@ -0,0 +1,7 @@
+package rip.crit.twist.ecdsa
+
+interface Ecdsa {
+    fun sign(message: ByteArray, privateKey: ByteArray): ByteArray
+
+    fun verify(message: ByteArray, signature: ByteArray, publicKey: ByteArray): Boolean
+}
--- a/app/src/main/kotlin/rip/crit/twist/ecdsa/Secp256k1Ecdsa.kt
+++ b/app/src/main/kotlin/rip/crit/twist/ecdsa/Secp256k1Ecdsa.kt
@ -0,0 +1,134 @@
+package rip.crit.twist.ecdsa
+
+import java.math.BigInteger
+import rip.crit.twist.core.HmacSha256
+import rip.crit.twist.core.Sha256
+import rip.crit.twist.core.SmartDoc
+
+/**
+ * secp256k1 ECDSA with RFC 6979 nonces and raw 32-byte private, 65-byte public, and 64-byte
+ * signature encodings.
+ */
+@SmartDoc(
+    summary = "Deterministic secp256k1 ECDSA signing and verification.",
+    category = "Cryptography",
+)
+class Secp256k1Ecdsa : Ecdsa {
+    private data class Point(val x: BigInteger, val y: BigInteger)
+
+    private val p =
+        BigInteger("FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFEFFFFFC2F", 16)
+    private val n =
+        BigInteger("FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFEBAAEDCE6AF48A03BBFD25E8CD0364141", 16)
+    private val g =
+        Point(
+            BigInteger("79BE667EF9DCBBAC55A06295CE870B07029BFCDB2DCE28D959F2815B16F81798", 16),
+            BigInteger("483ADA7726A3C4655DA4FBFC0E1108A8FD17B448A68554199C47D08FFB10D4B8", 16),
+        )
+
+    fun publicKey(privateKey: ByteArray): ByteArray {
+        val d = scalar(privateKey)
+        val q = multiply(g, d)!!
+        return byteArrayOf(4) + fixed(q.x) + fixed(q.y)
+    }
+
+    override fun sign(message: ByteArray, privateKey: ByteArray): ByteArray {
+        val d = scalar(privateKey)
+        val z = BigInteger(1, Sha256.bytes(message))
+        var k = nonce(d, z)
+        while (true) {
+            val r = multiply(g, k)!!.x.mod(n)
+            if (r != BigInteger.ZERO) {
+                var s = k.modInverse(n).multiply(z + r * d).mod(n)
+                if (s != BigInteger.ZERO) {
+                    if (s > n.shiftRight(1)) s = n - s
+                    return fixed(r) + fixed(s)
+                }
+            }
+            k = k.add(BigInteger.ONE).mod(n)
+        }
+    }
+
+    override fun verify(message: ByteArray, signature: ByteArray, publicKey: ByteArray): Boolean =
+        runCatching {
+            require(signature.size == 64)
+            val r = BigInteger(1, signature.copyOfRange(0, 32))
+            val s = BigInteger(1, signature.copyOfRange(32, 64))
+            if (r <= BigInteger.ZERO || r >= n || s <= BigInteger.ZERO || s >= n) return false
+            val q = decode(publicKey)
+            val z = BigInteger(1, Sha256.bytes(message))
+            val w = s.modInverse(n)
+            val point = add(multiply(g, z * w % n), multiply(q, r * w % n)) ?: return false
+            point.x.mod(n) == r
+        }
+        .getOrDefault(false)
+
+    private fun scalar(bytes: ByteArray): BigInteger {
+        require(bytes.size == 32)
+        return BigInteger(1, bytes).also { require(it > BigInteger.ZERO && it < n) }
+    }
+
+    private fun decode(bytes: ByteArray): Point {
+        require(bytes.size == 65 && bytes[0].toInt() == 4)
+        val q =
+            Point(BigInteger(1, bytes.copyOfRange(1, 33)), BigInteger(1, bytes.copyOfRange(33, 65)))
+        require(
+            q.x.modPow(BigInteger.valueOf(3), p).add(BigInteger.valueOf(7)).mod(p) ==
+                q.y.modPow(BigInteger.TWO, p)
+        )
+        return q
+    }
+
+    private fun add(a: Point?, b: Point?): Point? {
+        if (a == null) return b
+        if (b == null) return a
+        if (a.x == b.x && a.y.add(b.y).mod(p) == BigInteger.ZERO) return null
+        val slope =
+            if (a == b)
+                a.x
+                    .pow(2)
+                    .multiply(BigInteger.valueOf(3))
+                    .multiply(a.y.multiply(BigInteger.TWO).modInverse(p))
+            else b.y.subtract(a.y).multiply(b.x.subtract(a.x).mod(p).modInverse(p))
+        val x = slope.pow(2).subtract(a.x).subtract(b.x).mod(p)
+        return Point(x, slope.multiply(a.x - x).subtract(a.y).mod(p))
+    }
+
+    private fun multiply(point: Point?, scalar: BigInteger): Point? {
+        var result: Point? = null
+        var addend = point
+        for (i in 0 until scalar.bitLength()) {
+            if (scalar.testBit(i)) result = add(result, addend)
+            addend = add(addend, addend)
+        }
+        return result
+    }
+
+    private fun nonce(d: BigInteger, z: BigInteger): BigInteger {
+        var v = ByteArray(32) { 1 }
+        var k = ByteArray(32)
+        val seed = fixed(d) + fixed(z.mod(n))
+        k = HmacSha256.digest(k, v + byteArrayOf(0) + seed)
+        v = HmacSha256.digest(k, v)
+        k = HmacSha256.digest(k, v + byteArrayOf(1) + seed)
+        v = HmacSha256.digest(k, v)
+        while (true) {
+            v = HmacSha256.digest(k, v)
+            val candidate = BigInteger(1, v)
+            if (candidate > BigInteger.ZERO && candidate < n) return candidate
+            k = HmacSha256.digest(k, v + byteArrayOf(0))
+            v = HmacSha256.digest(k, v)
+        }
+    }
+
+    private fun fixed(value: BigInteger): ByteArray {
+        val bytes = value.toByteArray()
+        return ByteArray(32).also {
+            bytes.copyInto(
+                it,
+                (32 - bytes.size).coerceAtLeast(0),
+                (bytes.size - 32).coerceAtLeast(0),
+            )
+        }
+    }
+}
--- a/app/src/main/kotlin/rip/crit/twist/gas/BasicGasMeter.kt
+++ b/app/src/main/kotlin/rip/crit/twist/gas/BasicGasMeter.kt
@ -0,0 +1,16 @@
+package rip.crit.twist.gas
+
+class OutOfGasException(message: String) : IllegalStateException(message)
+
+class BasicGasMeter(override val limit: GasLimit) : GasMeter {
+    private var consumed = 0L
+    override val used: GasUsed
+        get() = GasUsed(consumed)
+
+    override fun consume(units: Long) {
+        require(units >= 0) { "Gas units cannot be negative" }
+        if (units > limit.value - consumed)
+            throw OutOfGasException("Gas limit of ${limit.value} exceeded")
+        consumed += units
+    }
+}
--- a/app/src/main/kotlin/rip/crit/twist/gas/Gas.kt
+++ b/app/src/main/kotlin/rip/crit/twist/gas/Gas.kt
@ -0,0 +1,29 @@
+package rip.crit.twist.gas
+
+import java.math.BigInteger
+
+data class GasLimit(val value: Long) {
+    init {
+        require(value >= 0)
+    }
+}
+
+data class GasUsed(val value: Long) {
+    init {
+        require(value >= 0)
+    }
+}
+
+data class GasPrice(val value: BigInteger) {
+    init {
+        require(value >= BigInteger.ZERO)
+    }
+}
+
+interface GasMeter {
+    val limit: GasLimit
+
+    val used: GasUsed
+
+    fun consume(units: Long)
+}
--- a/app/src/main/kotlin/rip/crit/twist/gossip/GossipService.kt
+++ b/app/src/main/kotlin/rip/crit/twist/gossip/GossipService.kt
@ -0,0 +1,13 @@
+package rip.crit.twist.gossip
+
+import rip.crit.twist.p2p.NetworkMessage
+
+interface GossipService {
+    fun start()
+
+    fun stop()
+
+    fun publish(message: NetworkMessage)
+
+    fun subscribe(topic: String, handler: (NetworkMessage) -> Unit)
+}
--- a/app/src/main/kotlin/rip/crit/twist/gossip/InMemoryGossipService.kt
+++ b/app/src/main/kotlin/rip/crit/twist/gossip/InMemoryGossipService.kt
@ -0,0 +1,26 @@
+package rip.crit.twist.gossip
+
+import java.util.concurrent.ConcurrentHashMap
+import rip.crit.twist.p2p.NetworkMessage
+
+class InMemoryGossipService : GossipService {
+    private val subscriptions = ConcurrentHashMap<String, MutableList<(NetworkMessage) -> Unit>>()
+    private var running = false
+
+    override fun start() {
+        running = true
+    }
+
+    override fun stop() {
+        running = false
+    }
+
+    override fun publish(message: NetworkMessage) {
+        check(running)
+        subscriptions[message.topic]?.toList()?.forEach { it(message) }
+    }
+
+    override fun subscribe(topic: String, handler: (NetworkMessage) -> Unit) {
+        subscriptions.computeIfAbsent(topic) { mutableListOf() }.add(handler)
+    }
+}
--- a/app/src/main/kotlin/rip/crit/twist/jit/JitCompiler.kt
+++ b/app/src/main/kotlin/rip/crit/twist/jit/JitCompiler.kt
@ -0,0 +1,9 @@
+package rip.crit.twist.jit
+
+interface JitCompiler {
+    fun compile(bytecode: ByteArray): CompiledProgram
+}
+
+fun interface CompiledProgram {
+    fun invoke(input: ByteArray): ByteArray
+}
--- a/app/src/main/kotlin/rip/crit/twist/jit/LLVMBuilder.kt
+++ b/app/src/main/kotlin/rip/crit/twist/jit/LLVMBuilder.kt
@ -0,0 +1,35 @@
+package rip.crit.twist.jit
+
+class LLVMBuilder(val name: String, val module: String) {
+    fun bitcode(): ByteArray = module.encodeToByteArray()
+}
+
+class NativeLlvmRuntime(private val libraryName: String = "twist_llvm") {
+    private var loaded = false
+
+    fun load() {
+        if (!loaded) {
+            System.loadLibrary(libraryName)
+            loaded = true
+        }
+    }
+
+    fun compile(module: LLVMBuilder, optimizationLevel: Int = 2): NativeArtifact {
+        require(optimizationLevel in 0..3)
+        check(loaded) { "Native LLVM runtime is not loaded" }
+        return NativeArtifact(nativeCompile(module.name, module.bitcode(), optimizationLevel))
+    }
+
+    private external fun nativeCompile(
+        name: String,
+        bitcode: ByteArray,
+        optimizationLevel: Int,
+    ): ByteArray
+}
+
+data class NativeArtifact(val machineCode: ByteArray) {
+    override fun equals(other: Any?): Boolean =
+        other is NativeArtifact && machineCode.contentEquals(other.machineCode)
+
+    override fun hashCode(): Int = machineCode.contentHashCode()
+}
--- a/app/src/main/kotlin/rip/crit/twist/jit/ValidatedJitCompiler.kt
+++ b/app/src/main/kotlin/rip/crit/twist/jit/ValidatedJitCompiler.kt
@ -0,0 +1,13 @@
+package rip.crit.twist.jit
+
+/** Validates input once and binds it to an execution backend for repeat invocation. */
+class ValidatedJitCompiler(
+    private val validate: (ByteArray) -> Unit,
+    private val execute: (ByteArray, ByteArray) -> ByteArray,
+) : JitCompiler {
+    override fun compile(bytecode: ByteArray): CompiledProgram {
+        val immutableCode = bytecode.copyOf()
+        validate(immutableCode)
+        return CompiledProgram { input -> execute(immutableCode, input.copyOf()).copyOf() }
+    }
+}
--- a/app/src/main/kotlin/rip/crit/twist/merkle/MerkleTree.kt
+++ b/app/src/main/kotlin/rip/crit/twist/merkle/MerkleTree.kt
@ -0,0 +1,15 @@
+package rip.crit.twist.merkle
+
+import rip.crit.twist.core.Hash
+
+interface MerkleTree {
+    val root: Hash
+
+    fun proofFor(leaf: Hash): MerkleProof?
+}
+
+data class MerkleProof(
+    val leaf: Hash,
+    val siblings: List<Hash>,
+    val siblingOnLeft: List<Boolean> = emptyList(),
+)
--- a/app/src/main/kotlin/rip/crit/twist/merkle/Sha256MerkleTree.kt
+++ b/app/src/main/kotlin/rip/crit/twist/merkle/Sha256MerkleTree.kt
@ -0,0 +1,47 @@
+package rip.crit.twist.merkle
+
+import rip.crit.twist.core.Hash
+import rip.crit.twist.core.Sha256
+
+class Sha256MerkleTree(leaves: List<Hash>) : MerkleTree {
+    private val levels: List<List<Hash>>
+    override val root: Hash
+
+    init {
+        require(leaves.isNotEmpty()) { "A Merkle tree needs at least one leaf" }
+        val built = mutableListOf(leaves.toList())
+        while (built.last().size > 1) {
+            val level = built.last()
+            built +=
+                level.indices.step(2).map { index ->
+                    val left = level[index]
+                    Sha256.combine(left, level.getOrElse(index + 1) { left })
+                }
+        }
+        levels = built
+        root = levels.last().single()
+    }
+
+    override fun proofFor(leaf: Hash): MerkleProof? {
+        var index = levels.first().indexOf(leaf)
+        if (index < 0) return null
+        val siblings = mutableListOf<Hash>()
+        val siblingOnLeft = mutableListOf<Boolean>()
+        for (level in levels.dropLast(1)) {
+            val siblingIndex =
+                if (index % 2 == 0) (index + 1).takeIf { it < level.size } ?: index else index - 1
+            siblings += level[siblingIndex]
+            siblingOnLeft += index % 2 != 0
+            index /= 2
+        }
+        return MerkleProof(leaf, siblings, siblingOnLeft)
+    }
+}
+
+fun MerkleProof.verifies(expectedRoot: Hash): Boolean {
+    if (siblings.size != siblingOnLeft.size) return false
+    return siblings.indices.fold(leaf) { current, index ->
+        if (siblingOnLeft[index]) Sha256.combine(siblings[index], current)
+        else Sha256.combine(current, siblings[index])
+    } == expectedRoot
+}
--- a/app/src/main/kotlin/rip/crit/twist/miner/CpuMiner.kt
+++ b/app/src/main/kotlin/rip/crit/twist/miner/CpuMiner.kt
@ -0,0 +1,54 @@
+package rip.crit.twist.miner
+
+import java.util.concurrent.Callable
+import java.util.concurrent.Executors
+import java.util.concurrent.atomic.AtomicBoolean
+import java.util.concurrent.atomic.AtomicLong
+import rip.crit.twist.core.Hash
+import rip.crit.twist.proof.ProofOfWork
+
+data class MiningResult(val subject: Hash, val difficulty: Int, val proof: ProofOfWork?, val attempts: Long, val elapsedNanos: Long) {
+    constructor(proof: ProofOfWork?, attempts: Long, elapsedNanos: Long) : this(
+        proof?.subject ?: Hash.ZERO,
+        proof?.difficulty ?: 0,
+        proof,
+        attempts,
+        elapsedNanos,
+    )
+}
+
+/** Bounded multi-core miner. Difficulty is the number of leading zero hexadecimal digits. */
+class CpuMiner(private val threads: Int = Runtime.getRuntime().availableProcessors()) {
+    init {
+        require(threads > 0)
+    }
+
+    fun mine(subject: Hash, difficulty: Int, maxAttempts: Long): MiningResult {
+        require(difficulty in 0..64)
+        require(maxAttempts >= 0)
+        val started = System.nanoTime()
+        val found = AtomicBoolean(false)
+        val attempts = AtomicLong(0)
+        val executor = Executors.newFixedThreadPool(threads)
+        return try {
+            val tasks =
+                (0 until threads).map { lane ->
+                    Callable {
+                        var nonce = lane.toLong()
+                        while (nonce < maxAttempts && !found.get()) {
+                            attempts.incrementAndGet()
+                            val proof = ProofOfWork(subject, nonce, difficulty)
+                            if (proof.verify() && found.compareAndSet(false, true))
+                                return@Callable proof
+                            nonce += threads
+                        }
+                        null
+                    }
+                }
+            val proof = executor.invokeAll(tasks).firstNotNullOfOrNull { it.get() }
+            MiningResult(subject, difficulty, proof, attempts.get(), System.nanoTime() - started)
+        } finally {
+            executor.shutdownNow()
+        }
+    }
+}
--- a/app/src/main/kotlin/rip/crit/twist/mint/MintPolicy.kt
+++ b/app/src/main/kotlin/rip/crit/twist/mint/MintPolicy.kt
@ -0,0 +1,7 @@
+package rip.crit.twist.mint
+
+import rip.crit.twist.core.Amount
+
+fun interface MintPolicy {
+    fun rewardAt(height: Long): Amount
+}
--- a/app/src/main/kotlin/rip/crit/twist/mint/Policies.kt
+++ b/app/src/main/kotlin/rip/crit/twist/mint/Policies.kt
@ -0,0 +1,17 @@
+package rip.crit.twist.mint
+
+import rip.crit.twist.core.Amount
+
+class FixedRewardPolicy(private val reward: Amount) : MintPolicy {
+    override fun rewardAt(height: Long): Amount {
+        require(height >= 0)
+        return reward
+    }
+}
+
+class HalvingRewardPolicy(private val initial: Amount, private val interval: Long) : MintPolicy {
+    override fun rewardAt(height: Long): Amount {
+        require(height >= 0 && interval > 0)
+        return Amount(initial.value.shiftRight((height / interval).toInt()))
+    }
+}
--- a/app/src/main/kotlin/rip/crit/twist/ope/AccessParallelExecutor.kt
+++ b/app/src/main/kotlin/rip/crit/twist/ope/AccessParallelExecutor.kt
@ -0,0 +1,53 @@
+package rip.crit.twist.ope
+
+import java.util.concurrent.Callable
+import java.util.concurrent.Executors
+import rip.crit.twist.access.AccessList
+import rip.crit.twist.core.Transaction
+import rip.crit.twist.tvm.ExecutionResult
+
+/** Executes conflict-free batches concurrently while preserving input result order. */
+class AccessParallelExecutor(
+    private val access: (Transaction) -> AccessList,
+    private val executeOne: (Transaction) -> ExecutionResult,
+    private val threads: Int = Runtime.getRuntime().availableProcessors(),
+) : ParallelExecutor {
+    init {
+        require(threads > 0)
+    }
+
+    override fun execute(transactions: List<Transaction>): List<ExecutionResult> {
+        val indexed = transactions.mapIndexed { index, transaction ->
+            IndexedValue(index, transaction)
+        }
+        val pending = ArrayDeque(indexed)
+        val results = arrayOfNulls<ExecutionResult>(transactions.size)
+        val pool = Executors.newFixedThreadPool(threads)
+        try {
+            while (pending.isNotEmpty()) {
+                val batch = mutableListOf<IndexedValue<Transaction>>()
+                val deferred = ArrayDeque<IndexedValue<Transaction>>()
+                while (pending.isNotEmpty()) {
+                    val candidate = pending.removeFirst()
+                    if (batch.none { access(it.value).conflictsWith(access(candidate.value)) }) {
+                        batch += candidate
+                    } else {
+                        deferred += candidate
+                    }
+                }
+                pending.addAll(deferred)
+                val completed =
+                    pool.invokeAll(
+                        batch.map { item -> Callable { item.index to executeOne(item.value) } }
+                    )
+                completed.forEach { future ->
+                    val (index, result) = future.get()
+                    results[index] = result
+                }
+            }
+        } finally {
+            pool.shutdownNow()
+        }
+        return results.map { requireNotNull(it) }
+    }
+}
--- a/app/src/main/kotlin/rip/crit/twist/ope/ParallelExecutor.kt
+++ b/app/src/main/kotlin/rip/crit/twist/ope/ParallelExecutor.kt
@ -0,0 +1,8 @@
+package rip.crit.twist.ope
+
+import rip.crit.twist.core.Transaction
+import rip.crit.twist.tvm.ExecutionResult
+
+interface ParallelExecutor {
+    fun execute(transactions: List<Transaction>): List<ExecutionResult>
+}
--- a/app/src/main/kotlin/rip/crit/twist/ope/SequentialExecutor.kt
+++ b/app/src/main/kotlin/rip/crit/twist/ope/SequentialExecutor.kt
@ -0,0 +1,14 @@
+package rip.crit.twist.ope
+
+import rip.crit.twist.core.Transaction
+import rip.crit.twist.state.WorldState
+import rip.crit.twist.tvm.ExecutionResult
+import rip.crit.twist.tvm.VirtualMachine
+
+class SequentialExecutor(private val vm: VirtualMachine, private val state: WorldState) :
+    ParallelExecutor {
+    override fun execute(transactions: List<Transaction>): List<ExecutionResult> =
+        transactions.map {
+            vm.execute(it, state)
+        }
+}
--- a/app/src/main/kotlin/rip/crit/twist/p2p/Adapters.kt
+++ b/app/src/main/kotlin/rip/crit/twist/p2p/Adapters.kt
@ -0,0 +1,243 @@
+package rip.crit.twist.p2p
+
+import java.io.ByteArrayInputStream
+import java.io.ByteArrayOutputStream
+import java.io.DataInputStream
+import java.io.DataOutputStream
+import rip.crit.twist.core.Hash
+import rip.crit.twist.core.SmartDoc
+
+
+enum class NetworkAdapterKind {
+    DEVP2P,
+    LIBP2P,
+    TWIST_OVERLAY,
+}
+
+interface NetworkAdapter {
+    val kind: NetworkAdapterKind
+
+    fun encode(message: NetworkMessage): ByteArray
+
+    fun decode(frame: ByteArray): NetworkMessage
+}
+
+open class EnvelopeAdapter(override val kind: NetworkAdapterKind) : NetworkAdapter {
+    override fun encode(message: NetworkMessage): ByteArray =
+        listOf(
+                message.id.value,
+                message.topic,
+                message.payload.joinToString("") { "%02x".format(it) },
+            )
+            .joinToString("\n")
+            .encodeToByteArray()
+
+    override fun decode(frame: ByteArray): NetworkMessage {
+        val fields = frame.decodeToString().split("\n", limit = 3)
+        require(fields.size == 3)
+        val payload = fields[2].chunked(2).map { it.toInt(16).toByte() }.toByteArray()
+        return NetworkMessage(fields[1], payload, Hash(fields[0]))
+    }
+}
+
+data class ProtocolCapability(val name: String, val version: Int) {
+    init {
+        require(name.matches(Regex("[a-z0-9./-]{1,64}")))
+        require(version >= 0)
+    }
+}
+
+data class DevP2pHello(
+    val clientId: String,
+    val listenPort: Int,
+    val nodeId: PeerId,
+    val capabilities: Set<ProtocolCapability>,
+)
+
+data class Libp2pIdentify(
+    val peer: PeerId,
+    val protocols: Set<String>,
+    val addresses: Set<String>,
+)
+
+/** Twist-native capability negotiation with devp2p Hello RLP semantics. */
+@SmartDoc(
+    summary = "devp2p Hello/Ping/Pong/Disconnect RLP wire with capability negotiation.",
+    category = "Networking",
+)
+class DevP2pAdapter(
+    private val hello: DevP2pHello,
+    private val capabilityOffset: Int = 16,
+) : NetworkAdapter {
+  constructor(
+      capabilities: Set<ProtocolCapability> = setOf(ProtocolCapability("twist", 1))
+  ) : this(
+      DevP2pHello("twist/1.0.0", 0, PeerId("bootstrap"), capabilities),
+  )
+
+  override val kind: NetworkAdapterKind = NetworkAdapterKind.DEVP2P
+
+  fun helloFrame(): ByteArray =
+      byteArrayOf(Rlpx.MSG_HELLO.toByte()) + Rlpx.encodeHello(hello)
+
+  fun pingFrame(): ByteArray = byteArrayOf(Rlpx.MSG_PING.toByte()) + Rlpx.encodePing()
+
+  fun pongFrame(): ByteArray = byteArrayOf(Rlpx.MSG_PONG.toByte()) + Rlpx.encodePong()
+
+  fun disconnectFrame(reason: Int = Rlpx.DISC_REQUESTED): ByteArray =
+      byteArrayOf(Rlpx.MSG_DISCONNECT.toByte()) + Rlpx.encodeDisconnect(reason)
+
+  override fun encode(message: NetworkMessage): ByteArray =
+      Rlpx.encodeSubprotocolMessage(capabilityOffset, 0, WireEnvelope.encode(message))
+
+  override fun decode(frame: ByteArray): NetworkMessage {
+    val (subId, payload) = Rlpx.decodeSubprotocolMessage(frame, capabilityOffset)
+    require(subId == 0) { "Unknown devp2p-twist subprotocol id" }
+    return WireEnvelope.decode(payload)
+  }
+
+  fun decodeBase(frame: ByteArray): BaseMessage =
+      when ((frame[0].toInt() and 0xFF)) {
+        Rlpx.MSG_HELLO -> BaseMessage.Hello(Rlpx.decodeHello(frame.copyOfRange(1, frame.size)))
+        Rlpx.MSG_DISCONNECT ->
+            BaseMessage.Disconnect(Rlpx.decodeDisconnect(frame.copyOfRange(1, frame.size)))
+        Rlpx.MSG_PING -> BaseMessage.Ping
+        Rlpx.MSG_PONG -> BaseMessage.Pong
+        else -> error("Unknown devp2p base message")
+      }
+
+  fun negotiate(remote: DevP2pHello): Set<ProtocolCapability> =
+      hello.capabilities
+          .groupBy { it.name }
+          .mapNotNull { (name, local) ->
+            remote.capabilities
+                .filter { it.name == name }
+                .map { it.version }
+                .intersect(local.map { it.version }.toSet())
+                .maxOrNull()
+                ?.let { ProtocolCapability(name, it) }
+          }
+          .toSet()
+
+  sealed interface BaseMessage {
+    data class Hello(val hello: DevP2pHello) : BaseMessage
+    data class Disconnect(val reason: Int) : BaseMessage
+    data object Ping : BaseMessage
+    data object Pong : BaseMessage
+  }
+}
+
+/** libp2p multistream-select + Identify + Gossipsub-publish stream framing. */
+@SmartDoc(
+    summary = "libp2p multistream-select, Identify protobuf, and Gossipsub publish envelopes.",
+    category = "Networking",
+)
+class LibP2pAdapter(
+    private val protocols: Set<String> = setOf(Libp2p.GOSSIPSUB_PROTO),
+    private val agent: String = "twist/1.0.0",
+) : NetworkAdapter {
+  override val kind: NetworkAdapterKind = NetworkAdapterKind.LIBP2P
+
+  init {
+    require(protocols.all { it.startsWith('/') && it.length <= 128 })
+  }
+
+  fun multistreamHandshake(protocol: String = Libp2p.GOSSIPSUB_PROTO): ByteArray =
+      Libp2p.frameLsForTest(Libp2p.MULTISTREAM) +
+          Libp2p.multistreamPropose(protocol)
+
+  override fun encode(message: NetworkMessage): ByteArray {
+    val publish =
+        Libp2p.encodeGossipPublish(
+            message.id.value.encodeToByteArray(), message.payload, 0L, message.topic)
+    val header = Libp2p.yamuxHeader(Libp2p.YAMUX_DATA, 0, 1, publish.size)
+    return header + publish
+  }
+
+  override fun decode(frame: ByteArray): NetworkMessage {
+    require(frame.size >= 12)
+    val header = Libp2p.yamuxParse(frame.copyOfRange(0, 12))
+    require(header.type == Libp2p.YAMUX_DATA)
+    val publish =
+        Libp2p.decodeGossipPublish(
+            frame.copyOfRange(12, 12 + header.length.coerceAtMost(frame.size - 12)))
+    return NetworkMessage(publish.topic, publish.data, Hash(publish.from.decodeToString()))
+  }
+
+  fun select(remoteProtocols: Set<String>): String? =
+      protocols.sorted().firstOrNull { it in remoteProtocols }
+
+  fun identify(peer: PeerId, addresses: Set<String>): Libp2pIdentify =
+      Libp2pIdentify(peer, protocols, addresses)
+
+  fun identifyFrame(peer: PeerId, addresses: Set<String>, observed: String = ""): ByteArray =
+      Libp2p.encodeIdentify(agent, protocols, observed, addresses)
+}
+
+class LocalPeerNetwork : PeerNetwork {
+    private val connected = linkedSetOf<PeerId>()
+
+    private var running = false
+
+    val received = mutableListOf<NetworkMessage>()
+
+    override fun start() {
+        running = true
+    }
+
+    override fun stop() {
+        running = false
+    }
+
+    override fun peers(): Set<PeerId> = connected.toSet()
+
+    override fun broadcast(message: NetworkMessage) {
+        check(running)
+        received += message
+    }
+
+    fun connect(peer: PeerId) {
+        connected += peer
+    }
+}
+
+object WireEnvelope {
+    private const val VERSION: Byte = 1
+    private const val MAX_FIELD_SIZE = 16 * 1024 * 1024
+
+    fun encode(message: NetworkMessage): ByteArray {
+        val output = ByteArrayOutputStream()
+        DataOutputStream(output).use { data ->
+            data.writeByte(VERSION.toInt())
+            val idBytes = message.id.value.encodeToByteArray()
+            require(idBytes.size <= MAX_FIELD_SIZE) { "Invalid id size" }
+            data.writeInt(idBytes.size)
+            data.write(idBytes)
+            val topicBytes = message.topic.encodeToByteArray()
+            require(topicBytes.size <= MAX_FIELD_SIZE) { "Invalid topic size" }
+            data.writeInt(topicBytes.size)
+            data.write(topicBytes)
+            require(message.payload.size <= MAX_FIELD_SIZE) { "Invalid payload size" }
+            data.writeInt(message.payload.size)
+            data.write(message.payload)
+        }
+        return output.toByteArray()
+    }
+
+    fun decode(bytes: ByteArray): NetworkMessage =
+        DataInputStream(ByteArrayInputStream(bytes)).use { input ->
+            require(input.readByte() == VERSION) { "Unsupported wire version" }
+            val idSize = input.readInt()
+            require(idSize in 0..MAX_FIELD_SIZE) { "Invalid id size" }
+            val idBytes = ByteArray(idSize).also(input::readFully)
+            val topicSize = input.readInt()
+            require(topicSize in 0..MAX_FIELD_SIZE) { "Invalid topic size" }
+            val topicBytes = ByteArray(topicSize).also(input::readFully)
+            val payloadSize = input.readInt()
+            require(payloadSize in 0..MAX_FIELD_SIZE) { "Invalid payload size" }
+            val payload = ByteArray(payloadSize).also(input::readFully)
+            require(input.available() == 0) { "Trailing message bytes" }
+            NetworkMessage(topicBytes.decodeToString(), payload, Hash(idBytes.decodeToString()))
+        }
+}
+
--- a/app/src/main/kotlin/rip/crit/twist/p2p/Dht.kt
+++ b/app/src/main/kotlin/rip/crit/twist/p2p/Dht.kt
@ -0,0 +1,47 @@
+package rip.crit.twist.p2p
+
+import java.time.Clock
+import java.time.Duration
+import java.time.Instant
+import java.util.concurrent.ConcurrentHashMap
+import rip.crit.twist.core.Hash
+
+data class PeerRecord(val peer: PeerId, val addresses: Set<String>, val expiresAt: Instant)
+
+interface DistributedHashTable {
+    fun put(key: Hash, record: PeerRecord)
+
+    fun get(key: Hash): PeerRecord?
+
+    fun closest(key: Hash, limit: Int = 20): List<PeerRecord>
+}
+
+class InMemoryDht(private val clock: Clock = Clock.systemUTC()) : DistributedHashTable {
+    private val records = ConcurrentHashMap<Hash, PeerRecord>()
+
+    override fun put(key: Hash, record: PeerRecord) {
+        require(record.expiresAt > clock.instant())
+        records[key] = record
+    }
+
+    override fun get(key: Hash): PeerRecord? =
+        records[key]?.takeIf { it.expiresAt > clock.instant() }
+
+    override fun closest(key: Hash, limit: Int): List<PeerRecord> {
+        require(limit > 0)
+        val target = key.value.toBigInteger(16)
+        return records.entries
+            .mapNotNull { (hash, record) ->
+                get(hash)?.let { (hash.value.toBigInteger(16).xor(target)) to it }
+            }
+            .sortedBy { it.first }
+            .take(limit)
+            .map { it.second }
+    }
+
+    fun announce(peer: PeerId, addresses: Set<String>, ttl: Duration = Duration.ofHours(1)): Hash {
+        val key = Hash(peer.value.padEnd(64, '0').take(64))
+        put(key, PeerRecord(peer, addresses, clock.instant().plus(ttl)))
+        return key
+    }
+}
--- a/app/src/main/kotlin/rip/crit/twist/p2p/FileDht.kt
+++ b/app/src/main/kotlin/rip/crit/twist/p2p/FileDht.kt
@ -0,0 +1,62 @@
+package rip.crit.twist.p2p
+
+import java.nio.file.Files
+import java.nio.file.Path
+import java.time.Clock
+import java.time.Instant
+import java.util.Base64
+import rip.crit.twist.core.Hash
+
+class FileDht(private val root: Path, private val clock: Clock = Clock.systemUTC()) :
+    DistributedHashTable {
+    init {
+        Files.createDirectories(root)
+    }
+
+    override fun put(key: Hash, record: PeerRecord) {
+        require(record.expiresAt > clock.instant())
+        Files.write(
+            root.resolve(key.value),
+            listOf(
+                record.peer.value,
+                record.expiresAt.toEpochMilli().toString(),
+                record.addresses.joinToString("\t") {
+                    Base64.getUrlEncoder().withoutPadding().encodeToString(it.encodeToByteArray())
+                },
+            ),
+        )
+    }
+
+    override fun get(key: Hash): PeerRecord? = runCatching {
+        val lines = Files.readAllLines(root.resolve(key.value))
+        val record =
+            PeerRecord(
+                PeerId(lines[0]),
+                lines[2]
+                    .split("\t")
+                    .filter(String::isNotEmpty)
+                    .map { Base64.getUrlDecoder().decode(it).decodeToString() }
+                    .toSet(),
+                Instant.ofEpochMilli(lines[1].toLong()),
+            )
+        record.takeIf { it.expiresAt > clock.instant() }
+    }
+        .getOrNull()
+
+    override fun closest(key: Hash, limit: Int): List<PeerRecord> {
+        require(limit > 0)
+        val target = key.value.toBigInteger(16)
+        return Files.list(root).use { paths ->
+            paths
+                .map { it.fileName.toString() }
+                .filter { it.matches(Regex("[0-9a-fA-F]+")) }
+                .map { Hash(it) }
+                .map { hash -> hash.value.toBigInteger(16).xor(target) to get(hash) }
+                .filter { it.second != null }
+                .sorted(compareBy { it.first })
+                .limit(limit.toLong())
+                .map { it.second!! }
+                .toList()
+        }
+    }
+}
--- a/app/src/main/kotlin/rip/crit/twist/p2p/Libp2p.kt
+++ b/app/src/main/kotlin/rip/crit/twist/p2p/Libp2p.kt
@ -0,0 +1,224 @@
+package rip.crit.twist.p2p
+
+import kotlin.random.Random
+import rip.crit.twist.core.HmacSha256
+import rip.crit.twist.core.SmartDoc
+
+/**
+ * libp2p transport shape (specs: multistream-select, Noise XX handshake, Yamux/mplex
+ * framing, Identify protobuf, Gossipsub v1.1 RPC).
+ *
+ * Multistream-select: initiator sends `/multistream/1.0.0\n`, then for each proposal
+ * `varint-len || "<proto>\n"`; responder answers `varint-len || "<proto>\n"` on accept
+ * or `varint-len || "na\n"` on reject.
+ *
+ * Noise XX (`[e, ->e/NoPayload, e...ee|s...es|s...se]`): three messages carrying
+ * ephemeral pubkeys, static pubkeys (encrypted), and payloads, chained with
+ * `MixHash/HKDF` into transport keys sealing subsequent frames with AES-GCM.
+ *
+ * Yamux: 12-byte header `version(1) || type || flags(2BE) || stream-id(4BE) || length(4BE)`
+ * with types Data(0), WindowUpdate(1), Ping(2), GoAway(3).
+ *
+ * Identify: protobuf with canonical field numbers (1 agent, 2 protocols, 3 observed-addr,
+ * 4 listen-addrs, 5 protocols-versions... simplified here to 1..4 + 6 public-key + 8-signed-peer-record
+ * envelope); Gossipsub RPC: `Publish(topic, seqno, from, data, signature)` with v1.1
+ * mesh parameters (`D=6, Dlo=4, Dhi=12, heartbeat=1s`).
+ *
+ * Twist profile: Noise DH/static payloads use bundled X25519 + HKDF-SHA256 + AES-GCM;
+ * protobuf fields use length-delimited varint encoding with the canonical field numbers above.
+ */
+object Libp2p {
+  const val MULTISTREAM = "/multistream/1.0.0"
+  const val NOISE_PROTO = "/noise"
+  const val YAMUX_PROTO = "/yamux/1.0.0"
+  const val MPLEX_PROTO = "/mplex/6.7.0"
+  const val IDENTIFY_PROTO = "/ipfs/id/1.0.0"
+  const val GOSSIPSUB_PROTO = "/meshsub/1.1.0"
+
+  const val YAMUX_DATA = 0
+  const val YAMUX_WINDOW = 1
+  const val YAMUX_PING = 2
+  const val YAMUX_GOAWAY = 3
+
+  const val GOSSIP_D = 6
+  const val GOSSIP_D_LO = 4
+  const val GOSSIP_D_HI = 12
+  const val GOSSIP_HEARTBEAT_MS = 1000L
+
+  fun frameLsForTest(line: String): ByteArray = frameLs("$line\n".encodeToByteArray())
+
+  fun multistreamPropose(protocol: String): ByteArray =
+      frameLs("$protocol\n".encodeToByteArray())
+
+  fun multistreamAccept(protocol: String): ByteArray =
+      frameLs("$protocol\n".encodeToByteArray())
+
+  fun multistreamReject(): ByteArray = frameLs("na\n".encodeToByteArray())
+
+  fun multistreamRead(frame: ByteArray): String {
+    val body = unframeLs(frame).decodeToString()
+    require(body.endsWith("\n")) { "Bad multistream line" }
+    return body.dropLast(1)
+  }
+
+  fun yamuxHeader(type: Int, flags: Int, streamId: Int, length: Int): ByteArray {
+    require(type in 0..3 && flags in 0..0xFFFF && length >= 0)
+    return byteArrayOf(
+        0,
+        type.toByte(),
+        ((flags ushr 8) and 0xFF).toByte(),
+        (flags and 0xFF).toByte(),
+        ((streamId ushr 24) and 0xFF).toByte(),
+        ((streamId ushr 16) and 0xFF).toByte(),
+        ((streamId ushr 8) and 0xFF).toByte(),
+        (streamId and 0xFF).toByte(),
+        ((length ushr 24) and 0xFF).toByte(),
+        ((length ushr 16) and 0xFF).toByte(),
+        ((length ushr 8) and 0xFF).toByte(),
+        (length and 0xFF).toByte())
+  }
+
+  fun yamuxParse(header: ByteArray): YamuxHeader {
+    require(header.size == 12 && header[0].toInt() == 0) { "Bad Yamux header" }
+    val type = header[1].toInt() and 0xFF
+    val flags = ((header[2].toInt() and 0xFF) shl 8) or (header[3].toInt() and 0xFF)
+    var streamId = 0
+    var length = 0
+    for (i in 4..7) streamId = (streamId shl 8) or (header[i].toInt() and 0xFF)
+    for (i in 8..11) length = (length shl 8) or (header[i].toInt() and 0xFF)
+    require(type in 0..3 && length >= 0)
+    return YamuxHeader(type, flags, streamId, length)
+  }
+
+  data class YamuxHeader(val type: Int, val flags: Int, val streamId: Int, val length: Int)
+
+  // ---- minimal protobuf (varint + length-delimited) with canonical Identify fields ----
+
+  fun varint(value: Long): ByteArray {
+    require(value >= 0)
+    var v = value
+    val out = mutableListOf<Byte>()
+    while (true) {
+      var b = (v and 0x7F).toInt()
+      v = v ushr 7
+      if (v != 0L) b = b or 0x80
+      out += b.toByte()
+      if (v == 0L) break
+    }
+    return out.toByteArray()
+  }
+
+  fun varintRead(bytes: ByteArray, offset: Int): Pair<Long, Int> {
+    var result = 0L
+    var shift = 0
+    var pos = offset
+    while (pos < bytes.size) {
+      val b = bytes[pos++].toInt() and 0xFF
+      result = result or ((b and 0x7F).toLong() shl shift)
+      shift += 7
+      require(shift <= 64) { "Varint overflow" }
+      if (b and 0x80 == 0) return Pair(result, pos)
+    }
+    error("Truncated varint")
+  }
+
+  fun field(number: Int, payload: ByteArray): ByteArray =
+      varint(((number shl 3) or 2).toLong()) + varint(payload.size.toLong()) + payload
+
+  fun fieldString(number: Int, value: String): ByteArray =
+      field(number, value.encodeToByteArray())
+
+  fun parseFields(bytes: ByteArray): Map<Int, List<ByteArray>> {
+    val out = mutableMapOf<Int, MutableList<ByteArray>>()
+    var pos = 0
+    while (pos < bytes.size) {
+      val (key, afterKey) = varintRead(bytes, pos)
+      pos = afterKey
+      require((key and 7) == 2L) { "Only length-delimited fields supported" }
+      val number = (key ushr 3).toInt()
+      val (len, afterLen) = varintRead(bytes, pos)
+      pos = afterLen
+      require(len in 0..16 * 1024 * 1024 && pos + len <= bytes.size) { "Bad protobuf length" }
+      out.getOrPut(number) { mutableListOf() } += bytes.copyOfRange(pos, pos + len.toInt())
+      pos += len.toInt()
+    }
+    return out
+  }
+
+  /** Identify fields: 1 agent, 2 protocols (repeated), 3 observed-addr, 4 listen-addrs (repeated). */
+  fun encodeIdentify(agent: String, protocols: Set<String>, observed: String, listen: Set<String>): ByteArray {
+    var out = fieldString(1, agent)
+    protocols.sorted().forEach { out += fieldString(2, it) }
+    out += fieldString(3, observed)
+    listen.sorted().forEach { out += fieldString(4, it) }
+    return out
+  }
+
+  fun decodeIdentify(bytes: ByteArray): Libp2pIdentifyFull {
+    val fields = parseFields(bytes)
+    val agent = fields[1]?.firstOrNull()?.decodeToString() ?: ""
+    val protocols = fields[2].orEmpty().map { it.decodeToString() }.toSet()
+    val observed = fields[3]?.firstOrNull()?.decodeToString() ?: ""
+    val listen = fields[4].orEmpty().map { it.decodeToString() }.toSet()
+    return Libp2pIdentifyFull(agent, protocols, observed, listen)
+  }
+
+  data class Libp2pIdentifyFull(
+      val agent: String,
+      val protocols: Set<String>,
+      val observedAddr: String,
+      val listenAddrs: Set<String>,
+  )
+
+  /** Gossipsub Publish fields: 1 from, 2 data, 3 seqno, 4 topic, 5 signature, 6 key. */
+  fun encodeGossipPublish(
+      from: ByteArray,
+      data: ByteArray,
+      seqno: Long,
+      topic: String,
+      signature: ByteArray = ByteArray(0),
+  ): ByteArray {
+    var out = field(1, from)
+    out += field(2, data)
+    out += field(3, seqnoBytes(seqno))
+    out += fieldString(4, topic)
+    if (signature.isNotEmpty()) out += field(5, signature)
+    return out
+  }
+
+  fun decodeGossipPublish(bytes: ByteArray): GossipPublish {
+    val fields = parseFields(bytes)
+    val from = fields[1]?.firstOrNull() ?: error("Gossip publish missing from")
+    val data = fields[2]?.firstOrNull() ?: error("Gossip publish missing data")
+    val seqnoRaw = fields[3]?.firstOrNull() ?: error("Gossip publish missing seqno")
+    require(seqnoRaw.size == 8)
+    var seqno = 0L
+    for (b in seqnoRaw) seqno = (seqno shl 8) or (b.toLong() and 0xFF)
+    val topic = fields[4]?.firstOrNull()?.decodeToString() ?: ""
+    return GossipPublish(from, data, seqno, topic, fields[5]?.firstOrNull() ?: ByteArray(0))
+  }
+
+  data class GossipPublish(
+      val from: ByteArray,
+      val data: ByteArray,
+      val seqno: Long,
+      val topic: String,
+      val signature: ByteArray,
+  )
+
+  private fun seqnoBytes(seqno: Long): ByteArray {
+    val out = ByteArray(8)
+    for (i in 0..7) out[7 - i] = ((seqno ushr (8 * i)) and 0xFF).toByte()
+    return out
+  }
+
+  private fun frameLs(body: ByteArray): ByteArray = varint(body.size.toLong()) + body
+
+  private fun unframeLs(frame: ByteArray): ByteArray {
+    val (len, pos) = varintRead(frame, 0)
+    require(len in 0..1024 && pos + len == frame.size.toLong()) { "Bad multistream frame" }
+    return frame.copyOfRange(pos, frame.size)
+  }
+}
+
+// NoiseXxSession / NoiseTransport: see transport/NoiseCrypto.kt.
--- a/app/src/main/kotlin/rip/crit/twist/p2p/PeerNetwork.kt
+++ b/app/src/main/kotlin/rip/crit/twist/p2p/PeerNetwork.kt
@ -0,0 +1,37 @@
+package rip.crit.twist.p2p
+
+import rip.crit.twist.core.Hash
+
+@JvmInline value class PeerId(val value: String)
+
+data class NetworkMessage(val topic: String, val payload: ByteArray, val id: Hash) {
+    override fun equals(other: Any?): Boolean {
+        if (this === other) return true
+        if (javaClass != other?.javaClass) return false
+
+        other as NetworkMessage
+
+        if (topic != other.topic) return false
+        if (!payload.contentEquals(other.payload)) return false
+        if (id != other.id) return false
+
+        return true
+    }
+
+    override fun hashCode(): Int {
+        var result = topic.hashCode()
+        result = 31 * result + payload.contentHashCode()
+        result = 31 * result + id.hashCode()
+        return result
+    }
+}
+
+interface PeerNetwork {
+    fun start()
+
+    fun stop()
+
+    fun peers(): Set<PeerId>
+
+    fun broadcast(message: NetworkMessage)
+}
--- a/app/src/main/kotlin/rip/crit/twist/p2p/ProtocolCatalog.kt
+++ b/app/src/main/kotlin/rip/crit/twist/p2p/ProtocolCatalog.kt
@ -0,0 +1,36 @@
+package rip.crit.twist.p2p
+
+import rip.crit.twist.core.TwistSpecific
+
+data class ProtocolDescriptor(
+    val name: String,
+    val version: String,
+    val transports: Set<String>,
+    val encrypted: Boolean,
+    val interoperable: Boolean,
+)
+
+object ProtocolCatalog {
+  val devP2p =
+      ProtocolDescriptor(
+          "devp2p-rlpx",
+          "rlpx-eip8-v4/twist-profile-v1",
+          setOf("tcp"),
+          true,
+          true,
+      )
+  val libP2p =
+      ProtocolDescriptor(
+          "libp2p-noise-yamux",
+          "noise-xx/yamux/meshsub-1.1.0",
+          setOf("tcp"),
+          true,
+          true,
+      )
+    private val twistOverlay =
+        ProtocolDescriptor("twist-overlay", "1.0", setOf("tcp", "memory"), true, true)
+
+    fun advertised(twistSpecific: TwistSpecific? = null): List<ProtocolDescriptor> =
+        listOf(devP2p, libP2p) +
+            if (twistSpecific === TwistSpecific.Enabled) listOf(twistOverlay) else emptyList()
+}
--- a/app/src/main/kotlin/rip/crit/twist/p2p/Rlp.kt
+++ b/app/src/main/kotlin/rip/crit/twist/p2p/Rlp.kt
@ -0,0 +1,145 @@
+package rip.crit.twist.p2p
+
+import java.io.ByteArrayOutputStream
+import java.math.BigInteger
+
+/**
+ * Ethereum Recursive Length Prefix (RLP) codec.
+ *
+ * Wire reference: ethereum/devp2p `rlpx.md` — RLPx framing, auth/ack handshake
+ * payloads, and devp2p Hello/Disconnect/Ping/Pong bodies are all RLP-encoded.
+ * Single-byte values < 0x80 are their own encoding; all other strings/lists use
+ * short (<=55 bytes) and long length prefixes.
+ */
+object PRlp {
+  private const val SHORT_MAX = 55
+
+  fun encodeString(bytes: ByteArray): ByteArray =
+      when {
+        bytes.size == 1 && (bytes[0].toInt() and 0xFF) < 0x80 -> bytes.copyOf()
+        bytes.size <= SHORT_MAX ->
+            byteArrayOf((0x80 + bytes.size).toByte()) + bytes
+        else -> {
+          val len = lengthBytes(bytes.size)
+          byteArrayOf((0xB7 + len.size).toByte()) + len + bytes
+        }
+      }
+
+  fun encodeInt(value: BigInteger): ByteArray {
+    require(value >= BigInteger.ZERO) { "RLP integers must be non-negative" }
+    if (value == BigInteger.ZERO) return byteArrayOf(0x80.toByte())
+    var raw = value.toByteArray().dropWhile { it == 0.toByte() }.toByteArray()
+    return encodeString(raw)
+  }
+
+  fun encodeInt(value: Long): ByteArray = encodeInt(BigInteger.valueOf(value))
+
+  fun encodeList(items: List<ByteArray>): ByteArray {
+    val payload = items.fold(ByteArray(0)) { acc, item -> acc + item }
+    return when {
+      payload.size <= SHORT_MAX ->
+          byteArrayOf((0xC0 + payload.size).toByte()) + payload
+      else -> {
+        val len = lengthBytes(payload.size)
+        byteArrayOf((0xF7 + len.size).toByte()) + len + payload
+      }
+    }
+  }
+
+  fun encodeElements(vararg items: ByteArray): ByteArray = encodeList(items.toList())
+
+  /** Decodes one RLP item starting at [offset]; returns (item, nextOffset). */
+  fun decodeOne(bytes: ByteArray, offset: Int = 0): Pair<PRlpItem, Int> {
+    require(offset < bytes.size) { "RLP truncated" }
+    val prefix = bytes[offset].toInt() and 0xFF
+    return when {
+      prefix < 0x80 -> Pair(PRlpItem.String(bytes.copyOfRange(offset, offset + 1)), offset + 1)
+      prefix <= 0xB7 -> {
+        val len = prefix - 0x80
+        require(offset + 1 + len <= bytes.size) { "RLP string truncated" }
+        Pair(PRlpItem.String(bytes.copyOfRange(offset + 1, offset + 1 + len)), offset + 1 + len)
+      }
+      prefix <= 0xBF -> {
+        val lenOfLen = prefix - 0xB7
+        val len = readLength(bytes, offset + 1, lenOfLen)
+        require(offset + 1 + lenOfLen + len <= bytes.size) { "RLP long string truncated" }
+        Pair(
+            PRlpItem.String(bytes.copyOfRange(offset + 1 + lenOfLen, offset + 1 + lenOfLen + len)),
+            offset + 1 + lenOfLen + len)
+      }
+      prefix <= 0xF7 -> {
+        val len = prefix - 0xC0
+        require(offset + 1 + len <= bytes.size) { "RLP list truncated" }
+        Pair(decodeList(bytes.copyOfRange(offset + 1, offset + 1 + len)), offset + 1 + len)
+      }
+      else -> {
+        val lenOfLen = prefix - 0xF7
+        val len = readLength(bytes, offset + 1, lenOfLen)
+        require(offset + 1 + lenOfLen + len <= bytes.size) { "RLP long list truncated" }
+        Pair(
+            decodeList(bytes.copyOfRange(offset + 1 + lenOfLen, offset + 1 + lenOfLen + len)),
+            offset + 1 + lenOfLen + len)
+      }
+    }
+  }
+
+  fun decode(bytes: ByteArray): PRlpItem {
+    val (item, next) = decodeOne(bytes, 0)
+    require(next == bytes.size) { "Trailing RLP bytes" }
+    return item
+  }
+
+  private fun decodeList(payload: ByteArray): PRlpItem.List {
+    val items = mutableListOf<PRlpItem>()
+    var offset = 0
+    while (offset < payload.size) {
+      val (item, next) = decodeOne(payload, offset)
+      items += item
+      offset = next
+    }
+    require(offset == payload.size) { "RLP list overrun" }
+    return PRlpItem.List(items)
+  }
+
+  private fun readLength(bytes: ByteArray, offset: Int, lenOfLen: Int): Int {
+    require(lenOfLen in 1..4 && offset + lenOfLen <= bytes.size) { "Bad RLP length prefix" }
+    require(bytes[offset] != 0.toByte()) { "RLP length has leading zero" }
+    var len = 0
+    for (i in 0 until lenOfLen) len = (len shl 8) or (bytes[offset + i].toInt() and 0xFF)
+    require(len > SHORT_MAX) { "RLP long form used for short payload" }
+    return len
+  }
+
+  private fun lengthBytes(size: Int): ByteArray {
+    val out = ByteArrayOutputStream()
+    var v = size
+    val tmp = mutableListOf<Byte>()
+    while (v > 0) {
+      tmp += (v and 0xFF).toByte()
+      v = v ushr 8
+    }
+    tmp.reversed().forEach { out.write(it.toInt()) }
+    return out.toByteArray()
+  }
+}
+
+sealed interface PRlpItem {
+  data class String(val bytes: ByteArray) : PRlpItem {
+    fun asLong(): Long {
+      require(bytes.isNotEmpty()) { "Empty RLP int" }
+      require(!(bytes.size > 1 && bytes[0] == 0.toByte())) { "Non-canonical RLP int" }
+      var v = 0L
+      for (b in bytes) v = (v shl 8) or (b.toLong() and 0xFF)
+      return v
+    }
+
+    fun asText(): kotlin.String = bytes.decodeToString()
+
+    override fun equals(other: Any?): Boolean =
+        other is String && bytes.contentEquals(other.bytes)
+
+    override fun hashCode(): Int = bytes.contentHashCode()
+  }
+
+  data class List(val items: kotlin.collections.List<PRlpItem>) : PRlpItem
+}
--- a/app/src/main/kotlin/rip/crit/twist/p2p/Rlpx.kt
+++ b/app/src/main/kotlin/rip/crit/twist/p2p/Rlpx.kt
@ -0,0 +1,187 @@
+package rip.crit.twist.p2p
+
+import kotlin.random.Random
+import rip.crit.twist.core.HmacSha256
+import rip.crit.twist.core.SmartDoc
+
+/**
+ * RLPx transport shape (ethereum/devp2p `rlpx.md`, EIP-8, wire `p2p.md`).
+ *
+ * Handshake: initiator -> auth (`uint16BE size || box || pad`), recipient -> ack (same
+ * framing). Plaintexts are RLP: `auth = [sig, initiator-pubkey, nonce, version]`,
+ * `ack = [recipient-ephemeral-pubkey, nonce, version]`; EIP-8 prefixes the RLP list with a
+ * one-byte version and appends random padding. Secrets derive as
+ * `ephemeral-shared = ECDH(ephemeral-priv, remote-ephemeral-pub)`,
+ * `HKDF(ephemeral-shared, nonce-initiator || nonce-recipient)` split into AES + MAC keys.
+ *
+ * Framing: 16-byte header `AES(mac-secret, egress-mac) XOR frame-size`, 16-byte header MAC,
+ * then AES-CTR frame-data `RLP([capability-message-id, payload...])` plus frame MAC; MACs
+ * form a SHA-256 egress/ingress chain over ciphertext.
+ *
+ * Twist profile: secp256k1/ECIES-KDF map onto bundled X25519 + HKDF-SHA256 + AES-GCM
+ * (auth/ack box) + AES-CTR (frame stream) + HMAC-SHA256 (MAC chain). RLP schemas,
+ * message-ids (Hello 0x00, Disconnect 0x01, Ping 0x02, Pong 0x03), disconnect reasons,
+ * and capability offset (`wire-id = capability-offset + subprotocol-id`) match devp2p.
+ */
+object Rlpx {
+  const val AUTH_VERSION = 4
+  const val PROTOCOL_VERSION = 5
+  const val NONCE_SIZE = 32
+  const val PUBKEY_SIZE = 32
+  const val SIG_SIZE = 64
+  const val GCM_NONCE_SIZE = 12
+  const val GCM_TAG_SIZE = 16
+  const val HEADER_SIZE = 16
+  const val MAC_SIZE = 16
+
+  const val MSG_HELLO = 0x00
+  const val MSG_DISCONNECT = 0x01
+  const val MSG_PING = 0x02
+  const val MSG_PONG = 0x03
+
+  // p2p disconnect reasons (`p2p.md`).
+  const val DISC_REQUESTED = 0x00
+  const val DISC_TCP_ERROR = 0x01
+  const val DISC_BAD_PROTOCOL = 0x02
+  const val DISC_USELESS_PEER = 0x03
+  const val DISC_TOO_MANY_PEERS = 0x04
+  const val DISC_ALREADY_CONNECTED = 0x05
+  const val DISC_INCOMPATIBLE_VERSION = 0x06
+  const val DISC_NULL_NODE = 0x07
+
+  data class AuthPlaintext(
+      val signature: ByteArray,
+      val initiatorPubkey: ByteArray,
+      val nonce: ByteArray,
+      val version: Int = AUTH_VERSION,
+  )
+
+  data class AckPlaintext(
+      val recipientEphemeralPubkey: ByteArray,
+      val nonce: ByteArray,
+      val version: Int = AUTH_VERSION,
+  )
+
+  data class Secrets(val aes: ByteArray, val mac: ByteArray)
+
+  fun encodeAuth(auth: AuthPlaintext): ByteArray {
+    require(auth.signature.size == SIG_SIZE && auth.initiatorPubkey.size == PUBKEY_SIZE)
+    require(auth.nonce.size == NONCE_SIZE)
+    return PRlp.encodeList(
+        listOf(
+            PRlp.encodeString(auth.signature),
+            PRlp.encodeString(auth.initiatorPubkey),
+            PRlp.encodeString(auth.nonce),
+            PRlp.encodeInt(auth.version.toLong())))
+  }
+
+  fun decodeAuth(bytes: ByteArray): AuthPlaintext {
+    val list = (PRlp.decode(bytes) as PRlpItem.List).items
+    require(list.size == 4)
+    val sig = (list[0] as PRlpItem.String).bytes
+    val pub = (list[1] as PRlpItem.String).bytes
+    val nonce = (list[2] as PRlpItem.String).bytes
+    require(sig.size == SIG_SIZE && pub.size == PUBKEY_SIZE && nonce.size == NONCE_SIZE)
+    return AuthPlaintext(sig, pub, nonce, (list[3] as PRlpItem.String).asLong().toInt())
+  }
+
+  fun encodeAck(ack: AckPlaintext): ByteArray {
+    require(ack.recipientEphemeralPubkey.size == PUBKEY_SIZE && ack.nonce.size == NONCE_SIZE)
+    return PRlp.encodeList(
+        listOf(
+            PRlp.encodeString(ack.recipientEphemeralPubkey),
+            PRlp.encodeString(ack.nonce),
+            PRlp.encodeInt(ack.version.toLong())))
+  }
+
+  fun decodeAck(bytes: ByteArray): AckPlaintext {
+    val list = (PRlp.decode(bytes) as PRlpItem.List).items
+    require(list.size == 3)
+    val pub = (list[0] as PRlpItem.String).bytes
+    val nonce = (list[1] as PRlpItem.String).bytes
+    require(pub.size == PUBKEY_SIZE && nonce.size == NONCE_SIZE)
+    return AckPlaintext(pub, nonce, (list[2] as PRlpItem.String).asLong().toInt())
+  }
+
+  // EIP-8 box seal/open and the AES-CTR frame cipher live in transport/RlpxCrypto.kt
+  // (transport sees p2p + wire + core; p2p must not depend back on transport).
+
+  /** `HKDF-SHA256(salt=nonces, ikm=shared)` expanded with info byte; mirrors rlpx secrets. */
+  fun deriveSecrets(shared: ByteArray, initiatorNonce: ByteArray, recipientNonce: ByteArray): Secrets {
+    val prk = HmacSha256.digest(initiatorNonce + recipientNonce, shared)
+    val aes = HmacSha256.digest(prk, byteArrayOf(1))
+    val mac = HmacSha256.digest(prk, byteArrayOf(2))
+    return Secrets(aes, mac)
+  }
+
+  fun hkdf(shared: ByteArray, context: ByteArray, size: Int): ByteArray {
+    val prk = HmacSha256.digest(ByteArray(32), shared)
+    var out = ByteArray(0)
+    var counter = 1
+    while (out.size < size) {
+      out += HmacSha256.digest(prk, context + counter.toByte())
+      counter++
+    }
+    return out.copyOf(size)
+  }
+
+  // ---- base-protocol RLP bodies (`p2p.md`) ----
+
+  fun encodeHello(hello: DevP2pHello): ByteArray =
+      PRlp.encodeList(
+          listOf(
+              PRlp.encodeInt(PROTOCOL_VERSION.toLong()),
+              PRlp.encodeString(hello.clientId.encodeToByteArray()),
+              PRlp.encodeList(
+                  hello.capabilities
+                      .sortedWith(compareBy({ it.name }, { it.version }))
+                      .map {
+                        PRlp.encodeList(
+                            listOf(
+                                PRlp.encodeString(it.name.encodeToByteArray()),
+                                PRlp.encodeInt(it.version.toLong())))
+                      }),
+              PRlp.encodeInt(hello.listenPort.toLong()),
+              PRlp.encodeString(hello.nodeId.value.encodeToByteArray())))
+
+  fun decodeHello(bytes: ByteArray): DevP2pHello {
+    val list = (PRlp.decode(bytes) as PRlpItem.List).items
+    require(list.size == 5) { "Hello must have 5 fields" }
+    require((list[0] as PRlpItem.String).asLong() == PROTOCOL_VERSION.toLong())
+    val clientId = (list[1] as PRlpItem.String).asText()
+    val caps =
+        ((list[2] as PRlpItem.List).items.map {
+          val cap = (it as PRlpItem.List).items
+          ProtocolCapability((cap[0] as PRlpItem.String).asText(), (cap[1] as PRlpItem.String).asLong().toInt())
+        }).toSet()
+    val port = (list[3] as PRlpItem.String).asLong().toInt()
+    val nodeId = PeerId((list[4] as PRlpItem.String).asText())
+    return DevP2pHello(clientId, port, nodeId, caps)
+  }
+
+  fun encodeDisconnect(reason: Int): ByteArray =
+      PRlp.encodeList(listOf(PRlp.encodeInt(reason.toLong())))
+
+  fun decodeDisconnect(bytes: ByteArray): Int {
+    val list = (PRlp.decode(bytes) as PRlpItem.List).items
+    return if (list.isEmpty()) DISC_REQUESTED else (list[0] as PRlpItem.String).asLong().toInt()
+  }
+
+  fun encodePing(): ByteArray = PRlp.encodeList(emptyList())
+
+  fun encodePong(): ByteArray = PRlp.encodeList(emptyList())
+
+  /** Subprotocol framing: `RLP([wire-id, payload...])`, `wire-id = offset + sub-id`. */
+  fun encodeSubprotocolMessage(capabilityOffset: Int, subprotocolId: Int, payload: ByteArray): ByteArray =
+      PRlp.encodeList(listOf(PRlp.encodeInt((capabilityOffset + subprotocolId).toLong()), PRlp.encodeString(payload)))
+
+  fun decodeSubprotocolMessage(bytes: ByteArray, capabilityOffset: Int): Pair<Int, ByteArray> {
+    val list = (PRlp.decode(bytes) as PRlpItem.List).items
+    require(list.size == 2)
+    val wireId = (list[0] as PRlpItem.String).asLong().toInt()
+    require(wireId >= capabilityOffset) { "Message id below capability offset" }
+    return Pair(wireId - capabilityOffset, (list[1] as PRlpItem.String).bytes)
+  }
+}
+
+// RlpxFrameCipher: see transport/RlpxCrypto.kt.
--- a/app/src/main/kotlin/rip/crit/twist/proof/Proof.kt
+++ b/app/src/main/kotlin/rip/crit/twist/proof/Proof.kt
@ -0,0 +1,109 @@
+package rip.crit.twist.proof
+
+import rip.crit.twist.core.Hash
+import rip.crit.twist.core.Sha256
+
+interface Proof {
+    val scheme: String
+
+    val subject: Hash
+
+    fun verify(): Boolean
+}
+
+data class ProofOfStore(override val subject: Hash, val challenge: Hash, val response: Hash) :
+    Proof {
+    override val scheme: String = "proof-of-store-v1"
+
+    override fun verify(): Boolean =
+        response == rip.crit.twist.core.Sha256.combine(subject, challenge)
+
+    companion object {
+        fun create(subject: Hash, challenge: Hash): ProofOfStore =
+            ProofOfStore(subject, challenge, rip.crit.twist.core.Sha256.combine(subject, challenge))
+    }
+}
+
+data class ProofOfStake(
+    override val subject: Hash,
+    val validator: String,
+    val stake: java.math.BigInteger,
+    val epoch: Long,
+) : Proof {
+    override val scheme: String = "proof-of-stake-v1"
+
+    override fun verify(): Boolean = validator.isNotBlank() && stake.signum() > 0 && epoch >= 0
+}
+
+data class ProofOfWork(override val subject: Hash, val nonce: Long, val difficulty: Int) : Proof {
+    override val scheme: String = "proof-of-work-v1"
+
+    override fun verify(): Boolean =
+        nonce >= 0 &&
+            difficulty in 0..64 &&
+            rip.crit.twist.core.Sha256.digestUtf8("${subject.value}:$nonce")
+                .value
+                .take(difficulty)
+                .all { it == '0' }
+
+    companion object {
+        fun mine(subject: Hash, difficulty: Int, maxAttempts: Long = 1_000_000): ProofOfWork? {
+            require(difficulty in 0..64)
+            for (nonce in 0 until maxAttempts) {
+                val proof = ProofOfWork(subject, nonce, difficulty)
+                if (proof.verify()) return proof
+            }
+            return null
+        }
+    }
+}
+
+data class ProofOfAuthority(
+    override val subject: Hash,
+    val authority: String,
+    val signature: Hash,
+    val allowedAuthorities: Set<String>,
+) : Proof {
+    override val scheme: String = "proof-of-authority-v1"
+
+    override fun verify(): Boolean =
+        authority in allowedAuthorities &&
+            signature == rip.crit.twist.core.Sha256.digestUtf8("${subject.value}:$authority")
+
+    companion object {
+        fun sign(subject: Hash, authority: String, allowedAuthorities: Set<String>) =
+            ProofOfAuthority(
+                subject,
+                authority,
+                rip.crit.twist.core.Sha256.digestUtf8("${subject.value}:$authority"),
+                allowedAuthorities,
+            )
+    }
+}
+
+class DynamicProofVerifier(private val verifiers: Map<String, (Proof) -> Boolean> = emptyMap()) {
+    fun verify(proof: Proof): Boolean = verifiers[proof.scheme]?.invoke(proof) ?: proof.verify()
+}
+
+/** A value claim bound to a subject. Authenticity is supplied by the signed containing message. */
+data class ProofOfValue(
+    override val subject: Hash,
+    val beneficiary: String,
+    val value: java.math.BigInteger,
+    val commitment: Hash,
+) : Proof {
+    override val scheme: String = "proof-of-value-v1"
+
+    override fun verify(): Boolean =
+        beneficiary.isNotBlank() &&
+            value.signum() >= 0 &&
+            commitment == commit(subject, beneficiary, value)
+
+    companion object {
+        fun create(subject: Hash, beneficiary: String, value: java.math.BigInteger): ProofOfValue =
+            ProofOfValue(subject, beneficiary, value, commit(subject, beneficiary, value))
+
+        private fun commit(subject: Hash, beneficiary: String, value: java.math.BigInteger): Hash =
+            Sha256.digestUtf8("${subject.value}\u0000$beneficiary\u0000$value")
+    }
+}
--- a/app/src/main/kotlin/rip/crit/twist/reflect/NetworkReflector.kt
+++ b/app/src/main/kotlin/rip/crit/twist/reflect/NetworkReflector.kt
@ -0,0 +1,102 @@
+package rip.crit.twist.reflect
+
+import java.io.ByteArrayInputStream
+import java.io.ByteArrayOutputStream
+import java.io.DataInputStream
+import java.io.DataOutputStream
+import java.time.Clock
+import java.time.Instant
+import rip.crit.twist.p2p.PeerId
+import rip.crit.twist.store.KeyValueStore
+
+data class PeerObservation(
+    val peer: PeerId,
+    val addresses: Set<String>,
+    val neighbors: Set<PeerId>,
+    val observedAt: Instant,
+)
+
+fun interface PeerProbe {
+    fun inspect(peer: PeerId): PeerObservation?
+}
+
+class PeerIndex(private val store: KeyValueStore) {
+    fun put(observation: PeerObservation) =
+        store.put(key(observation.peer), ObservationCodec.encode(observation))
+
+    fun get(peer: PeerId): PeerObservation? = store.get(key(peer))?.let(ObservationCodec::decode)
+
+    private fun key(peer: PeerId) = "reflect:${peer.value}".encodeToByteArray()
+}
+
+data class CrawlReport(
+    val observations: List<PeerObservation>,
+    val failures: Set<PeerId>,
+    val truncated: Boolean,
+)
+
+/** Breadth-first network crawler with strict node and neighbor limits. */
+class NetworkReflector(
+    private val probe: PeerProbe,
+    private val index: PeerIndex,
+    private val clock: Clock = Clock.systemUTC(),
+) {
+    fun crawl(seeds: Collection<PeerId>, maximumPeers: Int = 1_000): CrawlReport {
+        require(maximumPeers > 0)
+        val queued = ArrayDeque(seeds.distinct())
+        val visited = linkedSetOf<PeerId>()
+        val observations = mutableListOf<PeerObservation>()
+        val failures = linkedSetOf<PeerId>()
+        while (queued.isNotEmpty() && visited.size < maximumPeers) {
+            val peer = queued.removeFirst()
+            if (!visited.add(peer)) continue
+            val observation = runCatching { probe.inspect(peer) }.getOrNull()
+            if (observation == null) {
+                failures += peer
+                continue
+            }
+            val normalized = observation.copy(observedAt = clock.instant())
+            index.put(normalized)
+            observations += normalized
+            normalized.neighbors.filterNot(visited::contains).forEach(queued::addLast)
+        }
+        return CrawlReport(observations, failures, queued.isNotEmpty())
+    }
+}
+
+private object ObservationCodec {
+    fun encode(value: PeerObservation): ByteArray =
+        ByteArrayOutputStream().use { buffer ->
+            DataOutputStream(buffer).use { output ->
+                output.writeUTF(value.peer.value)
+                output.writeLong(value.observedAt.toEpochMilli())
+                output.writeStrings(value.addresses)
+                output.writeStrings(value.neighbors.map { it.value }.toSet())
+            }
+            buffer.toByteArray()
+        }
+
+    fun decode(bytes: ByteArray): PeerObservation? = runCatching {
+        DataInputStream(ByteArrayInputStream(bytes)).use { input ->
+            val peer = PeerId(input.readUTF())
+            val instant = Instant.ofEpochMilli(input.readLong())
+            val addresses = input.readStrings()
+            val neighbors = input.readStrings().map(::PeerId).toSet()
+            require(input.available() == 0)
+            PeerObservation(peer, addresses, neighbors, instant)
+        }
+    }
+        .getOrNull()
+
+    private fun DataOutputStream.writeStrings(values: Set<String>) {
+        require(values.size <= 10_000)
+        writeInt(values.size)
+        values.sorted().forEach(::writeUTF)
+    }
+
+    private fun DataInputStream.readStrings(): Set<String> {
+        val count = readInt()
+        require(count in 0..10_000)
+        return buildSet(count) { repeat(count) { add(readUTF()) } }
+    }
+}
--- a/app/src/main/kotlin/rip/crit/twist/router/OffchainRouter.kt
+++ b/app/src/main/kotlin/rip/crit/twist/router/OffchainRouter.kt
@ -0,0 +1,244 @@
+package rip.crit.twist.router
+
+import java.io.ByteArrayOutputStream
+import java.io.DataOutputStream
+import java.math.BigInteger
+import rip.crit.twist.core.Address
+import rip.crit.twist.core.Amount
+import rip.crit.twist.core.Hash
+import rip.crit.twist.core.Sha256
+import rip.crit.twist.core.SmartDoc
+import rip.crit.twist.ecdsa.Secp256k1Ecdsa
+import rip.crit.twist.p2p.NetworkMessage
+import rip.crit.twist.p2p.PeerNetwork
+import rip.crit.twist.proof.DynamicProofVerifier
+import rip.crit.twist.proof.Proof
+import rip.crit.twist.proof.ProofOfValue
+import rip.crit.twist.proof.ProofOfWork
+import rip.crit.twist.store.KeyValueStore
+
+sealed interface ProofPolicy {
+    fun accepts(proof: Proof?, subject: Hash, worker: Address): Boolean
+
+    data object None : ProofPolicy {
+        override fun accepts(proof: Proof?, subject: Hash, worker: Address) = proof == null
+    }
+
+    data class Work(val minimumDifficulty: Int, val maximumAttempts: Long = 1_000_000) :
+        ProofPolicy {
+        init {
+            require(minimumDifficulty in 0..64)
+            require(maximumAttempts > 0)
+        }
+
+        override fun accepts(proof: Proof?, subject: Hash, worker: Address): Boolean =
+            proof is ProofOfWork &&
+                proof.subject == subject &&
+                proof.difficulty >= minimumDifficulty &&
+                proof.verify()
+    }
+
+    data class Value(val minimumValue: BigInteger) : ProofPolicy {
+        init {
+            require(minimumValue.signum() >= 0)
+        }
+
+        override fun accepts(proof: Proof?, subject: Hash, worker: Address): Boolean =
+            proof is ProofOfValue &&
+                proof.subject == subject &&
+                proof.beneficiary == worker.value &&
+                proof.value >= minimumValue &&
+                proof.verify()
+    }
+
+    class Dynamic(
+        private val acceptedSchemes: Set<String>,
+        private val verifier: DynamicProofVerifier = DynamicProofVerifier(),
+    ) : ProofPolicy {
+        override fun accepts(proof: Proof?, subject: Hash, worker: Address): Boolean =
+            proof != null &&
+                proof.subject == subject &&
+                proof.scheme in acceptedSchemes &&
+                verifier.verify(proof)
+    }
+}
+
+data class OffchainJob(
+    val id: Hash,
+    val requester: Address,
+    val payload: ByteArray,
+    val reward: Amount = Amount(BigInteger.ZERO),
+    val deadlineMillis: Long = Long.MAX_VALUE,
+    val proofPolicy: ProofPolicy = ProofPolicy.None,
+) {
+    init {
+        require(deadlineMillis >= 0)
+    }
+
+    override fun equals(other: Any?): Boolean {
+        if (this === other) return true
+        if (javaClass != other?.javaClass) return false
+
+        other as OffchainJob
+
+        if (deadlineMillis != other.deadlineMillis) return false
+        if (id != other.id) return false
+        if (requester != other.requester) return false
+        if (!payload.contentEquals(other.payload)) return false
+        if (reward != other.reward) return false
+        if (proofPolicy != other.proofPolicy) return false
+
+        return true
+    }
+
+    override fun hashCode(): Int {
+        var result = deadlineMillis.hashCode()
+        result = 31 * result + id.hashCode()
+        result = 31 * result + requester.hashCode()
+        result = 31 * result + payload.contentHashCode()
+        result = 31 * result + reward.hashCode()
+        result = 31 * result + proofPolicy.hashCode()
+        return result
+    }
+}
+
+class OffchainResult(
+    val jobId: Hash,
+    val worker: Address,
+    val output: ByteArray,
+    val proof: Proof?,
+    val signature: ByteArray,
+) {
+    val outputHash: Hash = Sha256.digest(output)
+}
+
+fun interface OffchainComputation {
+    fun compute(payload: ByteArray): ByteArray
+}
+
+interface ResultDistributor {
+    fun distribute(result: OffchainResult)
+}
+
+class NetworkResultDistributor(
+    private val network: PeerNetwork,
+    private val store: KeyValueStore? = null,
+    private val topic: String = "twist/offchain/results/v1",
+) : ResultDistributor {
+    override fun distribute(result: OffchainResult) {
+        val encoded = ResultEncoding.encode(result)
+        store?.put(result.jobId.value.encodeToByteArray(), encoded)
+        network.broadcast(NetworkMessage(topic, encoded, Sha256.digest(encoded)))
+    }
+}
+
+class OffchainWorker(
+    val address: Address,
+    private val privateKey: ByteArray,
+    val publicKey: ByteArray,
+    private val computation: OffchainComputation,
+    private val proofFactory: ((ProofPolicy, Hash, Address) -> Proof?)? = null,
+    private val signer: Secp256k1Ecdsa = Secp256k1Ecdsa(),
+) {
+    init {
+        require(signer.publicKey(privateKey).contentEquals(publicKey))
+    }
+
+    fun execute(job: OffchainJob): OffchainResult {
+        val output = computation.compute(job.payload.copyOf())
+        val outputHash = Sha256.digest(output)
+        val proof = createProof(job.proofPolicy, outputHash)
+        val unsigned = ResultEncoding.signingBytes(job.id, address, outputHash, proof)
+        return OffchainResult(job.id, address, output, proof, signer.sign(unsigned, privateKey))
+    }
+
+    private fun createProof(policy: ProofPolicy, subject: Hash): Proof? =
+        when (policy) {
+            ProofPolicy.None -> null
+            is ProofPolicy.Work ->
+                ProofOfWork.mine(subject, policy.minimumDifficulty, policy.maximumAttempts)
+                    ?: error("Proof of work search exhausted")
+            is ProofPolicy.Value -> ProofOfValue.create(subject, address.value, policy.minimumValue)
+            is ProofPolicy.Dynamic ->
+                requireNotNull(proofFactory?.invoke(policy, subject, address)) {
+                    "Dynamic proof policy requires a worker proof factory"
+                }
+        }
+}
+
+@SmartDoc(
+    summary = "Signed off-chain job routing with optional proof validation.",
+    category = "Routing",
+)
+class OffchainRouter(
+    private val distributor: ResultDistributor,
+    private val clockMillis: () -> Long = System::currentTimeMillis,
+    private val verifier: Secp256k1Ecdsa = Secp256k1Ecdsa(),
+) {
+    private val workers = linkedMapOf<Address, OffchainWorker>()
+
+    fun register(worker: OffchainWorker) {
+        require(worker.address !in workers) { "Worker already registered" }
+        workers[worker.address] = worker
+    }
+
+    fun route(job: OffchainJob, worker: Address? = null): OffchainResult {
+        require(clockMillis() <= job.deadlineMillis) { "Job deadline has passed" }
+        val selected = worker?.let(workers::get) ?: workers.values.firstOrNull()
+        requireNotNull(selected) { "No eligible worker registered" }
+        val result = selected.execute(job)
+        require(verify(job, result, selected.publicKey)) { "Worker result failed verification" }
+        distributor.distribute(result)
+        return result
+    }
+
+    fun verify(job: OffchainJob, result: OffchainResult, publicKey: ByteArray): Boolean {
+        if (result.jobId != job.id || result.outputHash != Sha256.digest(result.output))
+            return false
+        if (!job.proofPolicy.accepts(result.proof, result.outputHash, result.worker)) return false
+        return verifier.verify(
+            ResultEncoding.signingBytes(job.id, result.worker, result.outputHash, result.proof),
+            result.signature,
+            publicKey,
+        )
+    }
+
+    fun verify(job: OffchainJob, result: OffchainResult): Boolean =
+        workers[result.worker]?.let { verify(job, result, it.publicKey) } ?: false
+}
+
+object ResultEncoding {
+    fun signingBytes(jobId: Hash, worker: Address, outputHash: Hash, proof: Proof?): ByteArray =
+        bytes {
+            writeUTF(jobId.value)
+            writeUTF(worker.value)
+            writeUTF(outputHash.value)
+            writeUTF(proof?.scheme.orEmpty())
+            writeUTF(proof?.subject?.value.orEmpty())
+            writeUTF(proofDetails(proof))
+        }
+
+    fun encode(result: OffchainResult): ByteArray = bytes {
+        val signing = signingBytes(result.jobId, result.worker, result.outputHash, result.proof)
+        writeInt(signing.size)
+        write(signing)
+        writeInt(result.output.size)
+        write(result.output)
+        writeInt(result.signature.size)
+        write(result.signature)
+    }
+
+    private fun proofDetails(proof: Proof?): String =
+        when (proof) {
+            null -> ""
+            is ProofOfWork -> "${proof.nonce}:${proof.difficulty}"
+            is ProofOfValue -> "${proof.beneficiary}:${proof.value}:${proof.commitment.value}"
+            else -> proof.toString()
+        }
+
+    private fun bytes(write: DataOutputStream.() -> Unit): ByteArray =
+        ByteArrayOutputStream().use { buffer ->
+            DataOutputStream(buffer).use { it.write() }
+            buffer.toByteArray()
+        }
+}
--- a/app/src/main/kotlin/rip/crit/twist/rsa/Rsa.kt
+++ b/app/src/main/kotlin/rip/crit/twist/rsa/Rsa.kt
@ -0,0 +1,7 @@
+package rip.crit.twist.rsa
+
+interface Rsa {
+    fun encrypt(message: ByteArray, publicKey: ByteArray): ByteArray
+
+    fun decrypt(ciphertext: ByteArray, privateKey: ByteArray): ByteArray
+}
--- a/app/src/main/kotlin/rip/crit/twist/rsa/RsaOaep.kt
+++ b/app/src/main/kotlin/rip/crit/twist/rsa/RsaOaep.kt
@ -0,0 +1,122 @@
+package rip.crit.twist.rsa
+
+import java.math.BigInteger
+import rip.crit.twist.core.Sha256
+
+data class RsaPublicKey(val modulus: BigInteger, val exponent: BigInteger)
+
+data class RsaPrivateKey(val modulus: BigInteger, val exponent: BigInteger)
+
+data class RsaKeyPair(
+    val publicKey: RsaPublicKey,
+    val privateKey: RsaPrivateKey,
+) {
+    companion object {
+        fun fromPrimes(
+            p: BigInteger,
+            q: BigInteger,
+            e: BigInteger = BigInteger.valueOf(65537),
+        ): RsaKeyPair {
+            require(p.isProbablePrime(100) && q.isProbablePrime(100) && p != q)
+            val n = p * q
+            val lambda =
+                (p - BigInteger.ONE)
+                    .multiply(q - BigInteger.ONE)
+                    .divide((p - BigInteger.ONE).gcd(q - BigInteger.ONE))
+            require(e.gcd(lambda) == BigInteger.ONE)
+            return RsaKeyPair(
+                RsaPublicKey(n, e),
+                RsaPrivateKey(n, e.modInverse(lambda)),
+            )
+        }
+    }
+}
+
+/** RFC 8017 RSAES-OAEP primitive with caller-supplied randomness. */
+object RsaOaep {
+    fun encrypt(
+        message: ByteArray,
+        key: RsaPublicKey,
+        seed: ByteArray,
+        label: ByteArray = byteArrayOf(),
+    ): ByteArray {
+        val k = (key.modulus.bitLength() + 7) / 8
+        val h = Sha256.bytes(label)
+        require(seed.size == 32 && message.size <= k - 66)
+        val db = h + ByteArray(k - message.size - 66) + byteArrayOf(1) + message
+        val dbMask = mgf(seed, k - 33)
+        val maskedDb = xor(db, dbMask)
+        val seedMask = mgf(maskedDb, 32)
+        return i2osp(
+            BigInteger(
+                    1,
+                    byteArrayOf(0) + xor(seed, seedMask) + maskedDb,
+                )
+                .modPow(key.exponent, key.modulus),
+            k,
+        )
+    }
+
+    fun decrypt(
+        ciphertext: ByteArray,
+        key: RsaPrivateKey,
+        label: ByteArray = byteArrayOf(),
+    ): ByteArray {
+        val k = (key.modulus.bitLength() + 7) / 8
+        require(ciphertext.size == k)
+        val encoded = i2osp(BigInteger(1, ciphertext).modPow(key.exponent, key.modulus), k)
+        require(encoded[0].toInt() == 0)
+        val maskedSeed = encoded.copyOfRange(1, 33)
+        val maskedDb = encoded.copyOfRange(33, k)
+        val seed = xor(maskedSeed, mgf(maskedDb, 32))
+        val db = xor(maskedDb, mgf(seed, k - 33))
+        require(db.copyOfRange(0, 32).contentEquals(Sha256.bytes(label)))
+        var index = 32
+        while (index < db.size && db[index].toInt() == 0) index++
+        require(index < db.size && db[index].toInt() == 1)
+        return db.copyOfRange(
+            index + 1,
+            db.size,
+        )
+    }
+
+    private fun mgf(seed: ByteArray, length: Int): ByteArray {
+        val output = ByteArray(length)
+        var offset = 0
+        var counter = 0
+        while (offset < length) {
+            val c =
+                byteArrayOf(
+                    (counter ushr 24).toByte(),
+                    (counter ushr 16).toByte(),
+                    (counter ushr 8).toByte(),
+                    counter.toByte(),
+                )
+            val hash = Sha256.bytes(seed + c)
+            hash.copyInto(
+                output,
+                offset,
+                0,
+                minOf(hash.size, length - offset),
+            )
+            offset += hash.size
+            counter++
+        }
+        return output
+    }
+
+    private fun xor(a: ByteArray, b: ByteArray) =
+        ByteArray(a.size) { (a[it].toInt() xor b[it].toInt()).toByte() }
+
+    private fun i2osp(value: BigInteger, size: Int): ByteArray {
+        val source = value.toByteArray()
+        require(source.size <= size + 1)
+        return ByteArray(size).also {
+            source.copyInto(
+                it,
+                (size - source.size).coerceAtLeast(0),
+                (source.size - size).coerceAtLeast(0),
+            )
+        }
+    }
+}
--- a/app/src/main/kotlin/rip/crit/twist/smartdoc/SmartDocGenerator.kt
+++ b/app/src/main/kotlin/rip/crit/twist/smartdoc/SmartDocGenerator.kt
@ -0,0 +1,96 @@
+package rip.crit.twist.smartdoc
+
+import java.nio.file.Files
+import java.nio.file.Path
+import kotlin.io.path.extension
+import kotlin.io.path.name
+
+data class SmartDocEntry(
+    val name: String,
+    val packageName: String,
+    val category: String,
+    val summary: String,
+    val stability: String,
+    val source: String,
+)
+
+object SmartDocGenerator {
+    fun generate(sourceRoot: Path, output: Path): List<SmartDocEntry> {
+        val root =
+            if (Files.isDirectory(sourceRoot)) {
+                sourceRoot
+            } else if (Files.isDirectory(Path.of("..").resolve(sourceRoot))) {
+                Path.of("..").resolve(sourceRoot).normalize()
+            } else if (Files.isDirectory(Path.of("../..").resolve(sourceRoot))) {
+                Path.of("../..").resolve(sourceRoot).normalize()
+            } else {
+                sourceRoot
+            }
+        require(Files.isDirectory(root)) { "Source directory does not exist: $sourceRoot (resolved: $root)" }
+        val entries =
+            Files.walk(root).use { paths ->
+                paths
+                    .filter { Files.isRegularFile(it) && it.extension == "kt" }
+                    .flatMap { path -> parse(path, root).stream() }
+                    .sorted(compareBy(SmartDocEntry::category, SmartDocEntry::name))
+                    .toList()
+            }
+        Files.createDirectories(output)
+        Files.writeString(output.resolve("index.html"), page(entries))
+        Files.writeString(output.resolve("api.json"), json(entries))
+        return entries
+    }
+
+    private fun parse(path: Path, root: Path): List<SmartDocEntry> {
+        val source = Files.readString(path)
+        val packageName = PACKAGE.find(source)?.groupValues?.get(1).orEmpty()
+        return ANNOTATION.findAll(source)
+            .mapNotNull { match ->
+                val tail = source.substring(match.range.last + 1)
+                val declaration = DECLARATION.find(tail) ?: return@mapNotNull null
+                SmartDocEntry(
+                    declaration.groupValues[2],
+                    packageName,
+                    match.groupValues[2],
+                    match.groupValues[1],
+                    match.groupValues[3].ifBlank { "experimental" },
+                    root.relativize(path).toString(),
+                )
+            }
+            .toList()
+    }
+
+    private fun page(entries: List<SmartDocEntry>): String =
+        """
+        <!doctype html>
+        <html lang="en"><head><meta charset="utf-8"><meta name="viewport" content="width=device-width,initial-scale=1">
+        <title>Twist SmartDoc API</title><style>
+        body{font:16px system-ui,sans-serif;max-width:960px;margin:3rem auto;padding:0 1rem;color:#18212f;background:#f8fafc}
+        h1{color:#5b21b6}.entry{background:white;border:1px solid #dbe3ef;border-radius:8px;padding:1rem;margin:.75rem 0}
+        code{color:#0f766e}.tag{float:right;color:#475569;font-size:.85rem}
+        </style></head><body><h1>Twist SmartDoc API</h1><p>${entries.size} documented public APIs.</p>
+        ${entries.joinToString("\n") { entry -> "<article class=\"entry\"><span class=\"tag\">${escape(entry.category)} · ${escape(entry.stability)}</span><h2>${escape(entry.name)}</h2><code>${escape(entry.packageName)}</code><p>${escape(entry.summary)}</p><small>${escape(entry.source)}</small></article>" }}
+        </body></html>
+        """
+            .trimIndent()
+
+    private fun json(entries: List<SmartDocEntry>): String =
+        entries.joinToString(",", "[", "]") {
+            "{\"name\":\"${escape(it.name)}\",\"package\":\"${escape(it.packageName)}\",\"category\":\"${escape(it.category)}\",\"summary\":\"${escape(it.summary)}\",\"stability\":\"${escape(it.stability)}\",\"source\":\"${escape(it.source)}\"}"
+        }
+
+    private fun escape(value: String): String =
+        value
+            .replace("&", "&amp;")
+            .replace("<", "&lt;")
+            .replace(">", "&gt;")
+            .replace("\"", "&quot;")
+
+    private val PACKAGE = Regex("(?m)^package\\s+([\\w.]+)")
+    private val ANNOTATION =
+        Regex(
+            "@SmartDoc\\(\\s*summary\\s*=\\s*\"([^\"]+)\"\\s*,\\s*category\\s*=\\s*\"([^\"]+)\"(?:\\s*,\\s*stability\\s*=\\s*\"([^\"]+)\")?,?\\s*\\)"
+        )
+    private val DECLARATION =
+        Regex("(?:public\\s+)?(class|object|fun|interface)\\s+([A-Za-z_][A-Za-z0-9_]*)")
+}
--- a/app/src/main/kotlin/rip/crit/twist/stake/InMemoryStaking.kt
+++ b/app/src/main/kotlin/rip/crit/twist/stake/InMemoryStaking.kt
@ -0,0 +1,25 @@
+package rip.crit.twist.stake
+
+import java.math.BigInteger
+import java.util.concurrent.ConcurrentHashMap
+import rip.crit.twist.core.Address
+import rip.crit.twist.core.Amount
+
+class InMemoryStaking : Staking {
+    private val delegations = ConcurrentHashMap<Pair<Address, Address>, Amount>()
+
+    override fun stake(delegator: Address, validator: Address, amount: Amount) {
+        require(amount.value > BigInteger.ZERO)
+        delegations.compute(delegator to validator) { _, current ->
+            Amount((current?.value ?: BigInteger.ZERO) + amount.value)
+        }
+    }
+
+    override fun votingPower(validator: Address): Amount =
+        Amount(
+            delegations
+                .filterKeys { it.second == validator }
+                .values
+                .fold(BigInteger.ZERO) { total, amount -> total + amount.value }
+        )
+}
--- a/app/src/main/kotlin/rip/crit/twist/stake/PersistentStaking.kt
+++ b/app/src/main/kotlin/rip/crit/twist/stake/PersistentStaking.kt
@ -0,0 +1,25 @@
+package rip.crit.twist.stake
+
+import java.math.BigInteger
+import rip.crit.twist.core.Address
+import rip.crit.twist.core.Amount
+import rip.crit.twist.store.KeyValueStore
+
+class PersistentStaking(private val store: KeyValueStore) : Staking {
+    override fun stake(delegator: Address, validator: Address, amount: Amount) {
+        require(amount.value > BigInteger.ZERO)
+        val key = delegationKey(delegator, validator)
+        val current = store.get(key)?.let(::BigInteger) ?: BigInteger.ZERO
+        store.put(key, (current + amount.value).toByteArray())
+        val total = store.get(totalKey(validator))?.let(::BigInteger) ?: BigInteger.ZERO
+        store.put(totalKey(validator), (total + amount.value).toByteArray())
+    }
+
+    override fun votingPower(validator: Address): Amount =
+        Amount(store.get(totalKey(validator))?.let(::BigInteger) ?: BigInteger.ZERO)
+
+    private fun delegationKey(delegator: Address, validator: Address) =
+        "delegation:${delegator.value}:${validator.value}".encodeToByteArray()
+
+    private fun totalKey(validator: Address) = "validator:${validator.value}".encodeToByteArray()
+}
--- a/app/src/main/kotlin/rip/crit/twist/stake/Staking.kt
+++ b/app/src/main/kotlin/rip/crit/twist/stake/Staking.kt
@ -0,0 +1,10 @@
+package rip.crit.twist.stake
+
+import rip.crit.twist.core.Address
+import rip.crit.twist.core.Amount
+
+interface Staking {
+    fun stake(delegator: Address, validator: Address, amount: Amount)
+
+    fun votingPower(validator: Address): Amount
+}
--- a/app/src/main/kotlin/rip/crit/twist/standards/InMemoryToken.kt
+++ b/app/src/main/kotlin/rip/crit/twist/standards/InMemoryToken.kt
@ -0,0 +1,25 @@
+package rip.crit.twist.standards
+
+import java.math.BigInteger
+import java.util.concurrent.ConcurrentHashMap
+import rip.crit.twist.core.Address
+import rip.crit.twist.core.Amount
+
+class InMemoryToken(
+    override val symbol: String,
+    initialBalances: Map<Address, Amount> = emptyMap(),
+) : TokenStandard {
+    private val balances = ConcurrentHashMap(initialBalances)
+
+    override fun balanceOf(owner: Address): Amount = balances[owner] ?: Amount(BigInteger.ZERO)
+
+    override fun transfer(from: Address, to: Address, amount: Amount): Boolean =
+        synchronized(this) {
+            if (amount.value == BigInteger.ZERO || balanceOf(from).value < amount.value) false
+            else {
+                balances[from] = Amount(balanceOf(from).value - amount.value)
+                balances[to] = Amount(balanceOf(to).value + amount.value)
+                true
+            }
+        }
+}
--- a/app/src/main/kotlin/rip/crit/twist/standards/PersistentToken.kt
+++ b/app/src/main/kotlin/rip/crit/twist/standards/PersistentToken.kt
@ -0,0 +1,28 @@
+package rip.crit.twist.standards
+
+import java.math.BigInteger
+import rip.crit.twist.core.Address
+import rip.crit.twist.core.Amount
+import rip.crit.twist.store.KeyValueStore
+
+class PersistentToken(override val symbol: String, private val store: KeyValueStore) :
+    TokenStandard {
+    override fun balanceOf(owner: Address): Amount =
+        Amount(store.get(key(owner))?.let(::BigInteger) ?: BigInteger.ZERO)
+
+    override fun transfer(from: Address, to: Address, amount: Amount): Boolean =
+        synchronized(this) {
+            val source = balanceOf(from).value
+            if (amount.value == BigInteger.ZERO || source < amount.value) return false
+            store.put(key(from), (source - amount.value).toByteArray())
+            store.put(key(to), (balanceOf(to).value + amount.value).toByteArray())
+            true
+        }
+
+    fun mint(to: Address, amount: Amount) =
+        synchronized(this) {
+            store.put(key(to), (balanceOf(to).value + amount.value).toByteArray())
+        }
+
+    private fun key(owner: Address) = "$symbol:${owner.value}".encodeToByteArray()
+}
--- a/app/src/main/kotlin/rip/crit/twist/standards/TokenStandard.kt
+++ b/app/src/main/kotlin/rip/crit/twist/standards/TokenStandard.kt
@ -0,0 +1,12 @@
+package rip.crit.twist.standards
+
+import rip.crit.twist.core.Address
+import rip.crit.twist.core.Amount
+
+interface TokenStandard {
+    val symbol: String
+
+    fun balanceOf(owner: Address): Amount
+
+    fun transfer(from: Address, to: Address, amount: Amount): Boolean
+}
--- a/app/src/main/kotlin/rip/crit/twist/state/FileNodeState.kt
+++ b/app/src/main/kotlin/rip/crit/twist/state/FileNodeState.kt
@ -0,0 +1,71 @@
+package rip.crit.twist.state
+
+import java.io.ObjectInputStream
+import java.io.ObjectOutputStream
+import java.nio.file.Files
+import java.nio.file.Path
+import java.nio.file.Paths
+import java.nio.file.StandardCopyOption
+import java.security.MessageDigest
+import java.util.Base64
+import java.util.concurrent.ConcurrentHashMap
+
+/** File-backed node state rooted at a caller-selected folder. */
+class FileNodeState(
+    private val root: Path = Paths.get(".twist", "nodes"),
+) : NodeState {
+    private val nodes = ConcurrentHashMap<String, Node>()
+
+    init {
+        Files.createDirectories(root)
+        Files.list(root).use { files ->
+            files.filter(Files::isRegularFile).forEach { file ->
+                runCatching {
+                    ObjectInputStream(Files.newInputStream(file)).use { input ->
+                        nodes[file.fileName.toString()] = input.readObject() as Node
+                    }
+                }
+            }
+        }
+    }
+
+    override fun getNode(key: String): Node? = nodes[safe(key)]
+
+    override fun putNode(key: String, node: Node) {
+        val filename = safe(key)
+        val target = root.resolve(filename)
+        val temporary = Files.createTempFile(root, "node-", ".tmp")
+        try {
+            ObjectOutputStream(Files.newOutputStream(temporary)).use { it.writeObject(node) }
+            Files.move(
+                temporary,
+                target,
+                StandardCopyOption.REPLACE_EXISTING,
+                StandardCopyOption.ATOMIC_MOVE,
+            )
+            nodes[filename] = node
+        } finally {
+            Files.deleteIfExists(temporary)
+        }
+    }
+
+    override fun rootHash(): String {
+        val digest = MessageDigest.getInstance("SHA-256")
+        Files.list(root).use { files ->
+            files.filter(Files::isRegularFile).sorted().forEach { file ->
+                digest.update(file.fileName.toString().encodeToByteArray())
+                digest.update(Files.readAllBytes(file))
+            }
+        }
+        return digest.digest().joinToString("") { "%02x".format(it) }
+    }
+
+    override fun snapshot(): StateSnapshot = FileNodeSnapshot(nodes.toMap())
+
+    private fun safe(value: String): String =
+        Base64.getUrlEncoder().withoutPadding().encodeToString(value.encodeToByteArray())
+}
+
+class FileNodeSnapshot internal constructor(internal val nodes: Map<String, Node>) : StateSnapshot {
+    override fun close() = Unit
+}
--- a/app/src/main/kotlin/rip/crit/twist/state/FileWorldState.kt
+++ b/app/src/main/kotlin/rip/crit/twist/state/FileWorldState.kt
@ -0,0 +1,116 @@
+package rip.crit.twist.state
+
+import java.math.BigInteger
+import java.nio.file.Files
+import java.nio.file.Path
+import java.nio.file.StandardCopyOption
+import java.util.Base64
+import rip.crit.twist.core.Address
+import rip.crit.twist.core.Amount
+import rip.crit.twist.core.Hash
+import rip.crit.twist.core.Sha256
+
+/** File-backed account and contract state rooted at a caller-selected folder. */
+class FileWorldState(private val root: Path) : ContractState {
+    private val accounts = root.resolve("accounts")
+    private val storage = root.resolve("storage")
+
+    init {
+        Files.createDirectories(accounts)
+        Files.createDirectories(storage)
+    }
+
+    override fun account(address: Address): Account? {
+        val lines =
+            path(accounts, address.value).takeIf(Files::exists)?.let(Files::readAllLines)
+                ?: return null
+        return Account(
+            lines[0].toLong(),
+            Amount(BigInteger(lines[1])),
+            Base64.getDecoder().decode(lines[2]),
+        )
+    }
+
+    override fun putAccount(address: Address, account: Account) =
+        write(
+            path(accounts, address.value),
+            listOf(
+                account.nonce.toString(),
+                account.balance.value.toString(),
+                Base64.getEncoder().encodeToString(account.code),
+            ),
+        )
+
+    override fun deleteAccount(address: Address) {
+        Files.deleteIfExists(path(accounts, address.value))
+        deleteStorage(address)
+    }
+
+    override fun storage(contract: Address, key: Hash): ByteArray? =
+        path(storage.resolve(safe(contract.value)), key.value)
+            .takeIf(Files::exists)
+            ?.let(Files::readAllBytes)
+
+    override fun putStorage(contract: Address, key: Hash, value: ByteArray) {
+        val directory = storage.resolve(safe(contract.value))
+        Files.createDirectories(directory)
+        writeBytes(path(directory, key.value), value)
+    }
+
+    override fun deleteStorage(contract: Address) {
+        val directory = storage.resolve(safe(contract.value))
+        if (!Files.exists(directory)) return
+        Files.walk(directory).use { paths ->
+            paths.sorted(Comparator.reverseOrder()).forEach(Files::deleteIfExists)
+        }
+    }
+
+    override fun rootHash(): Hash {
+        val content =
+            Files.walk(root).use { paths ->
+                paths
+                    .filter(Files::isRegularFile)
+                    .sorted()
+                    .flatMap { path ->
+                        java.util.stream.Stream.of(
+                            root.relativize(path).toString().encodeToByteArray(),
+                            Files.readAllBytes(path),
+                        )
+                    }
+                    .reduce(byteArrayOf()) { a, b -> a + b }
+            }
+        return Sha256.digest(content)
+    }
+
+    override fun snapshot(): StateSnapshot =
+        object : StateSnapshot {
+            override fun close() = Unit
+        }
+
+    private fun path(directory: Path, key: String) = directory.resolve(safe(key))
+
+    private fun safe(value: String) =
+        Base64.getUrlEncoder().withoutPadding().encodeToString(value.encodeToByteArray())
+
+    private fun write(target: Path, lines: List<String>) {
+        val temporary = Files.createTempFile(target.parent, "state-", ".tmp")
+        Files.write(temporary, lines)
+        Files.move(
+            temporary,
+            target,
+            StandardCopyOption.REPLACE_EXISTING,
+            StandardCopyOption.ATOMIC_MOVE,
+        )
+    }
+
+    private fun writeBytes(target: Path, value: ByteArray) {
+        val temporary = Files.createTempFile(target.parent, "slot-", ".tmp")
+        Files.write(temporary, value)
+        Files.move(
+            temporary,
+            target,
+            StandardCopyOption.REPLACE_EXISTING,
+            StandardCopyOption.ATOMIC_MOVE,
+        )
+    }
+}
--- a/app/src/main/kotlin/rip/crit/twist/state/InMemoryNodeState.kt
+++ b/app/src/main/kotlin/rip/crit/twist/state/InMemoryNodeState.kt
@ -0,0 +1,55 @@
+package rip.crit.twist.state
+
+import java.util.concurrent.ConcurrentHashMap
+import rip.crit.twist.core.Sha256
+
+class InMemoryNodeState : NodeState {
+    private val nodes = ConcurrentHashMap<String, Node>()
+
+    override fun getNode(key: String): Node? = nodes[key]?.deepCopy()
+
+    override fun putNode(key: String, node: Node) {
+        require(key.isNotBlank())
+        nodes[key] = node.deepCopy()
+    }
+
+    override fun rootHash(): String {
+        val bytes =
+            nodes.entries
+                .sortedBy { it.key }
+                .fold(byteArrayOf()) { output, (key, node) ->
+                    output + key.encodeToByteArray() + canonical(node)
+                }
+        return Sha256.digest(bytes).value
+    }
+
+    override fun snapshot(): StateSnapshot = NodeSnapshot(nodes.mapValues { it.value.deepCopy() })
+
+    private fun canonical(node: Node): ByteArray {
+        val storage =
+            node.storage.entries
+                .sortedBy { it.key }
+                .fold(byteArrayOf()) { output, entry ->
+                    output + entry.key.encodeToByteArray() + entry.value
+                }
+        return node.accounts.entries
+            .sortedBy { it.key }
+            .fold(storage) { output, entry ->
+                output +
+                    entry.key.encodeToByteArray() +
+                    entry.value.balance.toString().encodeToByteArray() +
+                    entry.value.nonce.toString().encodeToByteArray() +
+                    entry.value.code
+            }
+    }
+
+    private fun Node.deepCopy() =
+        copy(
+            storage = storage.mapValues { it.value.copyOf() },
+            accounts = accounts.mapValues { it.value.copy(code = it.value.code.copyOf()) },
+        )
+}
+
+class NodeSnapshot internal constructor(internal val nodes: Map<String, Node>) : StateSnapshot {
+    override fun close() = Unit
+}
--- a/app/src/main/kotlin/rip/crit/twist/state/InMemoryWorldState.kt
+++ b/app/src/main/kotlin/rip/crit/twist/state/InMemoryWorldState.kt
@ -0,0 +1,59 @@
+package rip.crit.twist.state
+
+import java.util.concurrent.ConcurrentHashMap
+import rip.crit.twist.core.Address
+import rip.crit.twist.core.Hash
+import rip.crit.twist.core.Sha256
+
+class InMemoryWorldState : ContractState {
+    private val accounts = ConcurrentHashMap<Address, Account>()
+    private val storage = ConcurrentHashMap<Pair<Address, Hash>, ByteArray>()
+
+    override fun account(address: Address): Account? =
+        accounts[address]?.let { it.copy(code = it.code.copyOf()) }
+
+    override fun putAccount(address: Address, account: Account) {
+        accounts[address] = account.copy(code = account.code.copyOf())
+    }
+
+    override fun deleteAccount(address: Address) {
+        accounts.remove(address)
+        deleteStorage(address)
+    }
+
+    override fun rootHash(): Hash =
+        Sha256.digestUtf8(
+            accounts.entries
+                .sortedBy { it.key.value }
+                .joinToString("|") { (address, account) ->
+                    "${address.value},${account.nonce},${account.balance.value},${
+                account.code.joinToString("") {
+                    "%02x".format(
+                        it
+                    )
+                }
+            }"
+                }
+        )
+
+    override fun snapshot(): StateSnapshot =
+        InMemorySnapshot(
+            accounts.mapValues { (_, account) -> account.copy(code = account.code.copyOf()) }
+        )
+
+    override fun storage(contract: Address, key: Hash): ByteArray? =
+        storage[contract to key]?.copyOf()
+
+    override fun putStorage(contract: Address, key: Hash, value: ByteArray) {
+        storage[contract to key] = value.copyOf()
+    }
+
+    override fun deleteStorage(contract: Address) {
+        storage.keys.removeIf { it.first == contract }
+    }
+}
+
+class InMemorySnapshot internal constructor(internal val accounts: Map<Address, Account>) :
+    StateSnapshot {
+    override fun close() = Unit
+}
--- a/app/src/main/kotlin/rip/crit/twist/state/NodeState.kt
+++ b/app/src/main/kotlin/rip/crit/twist/state/NodeState.kt
@ -0,0 +1,42 @@
+package rip.crit.twist.state
+
+data class Node(
+    val storage: Map<String, ByteArray> = emptyMap(),
+    val accounts: Map<String, AccountState> = emptyMap(),
+)
+
+data class AccountState(
+    val balance: Long = 0,
+    val nonce: Long = 0,
+    val code: ByteArray = ByteArray(0),
+) {
+    override fun equals(other: Any?): Boolean {
+        if (this === other) return true
+        if (javaClass != other?.javaClass) return false
+
+        other as AccountState
+
+        if (balance != other.balance) return false
+        if (nonce != other.nonce) return false
+        if (!code.contentEquals(other.code)) return false
+
+        return true
+    }
+
+    override fun hashCode(): Int {
+        var result = balance.hashCode()
+        result = 31 * result + nonce.hashCode()
+        result = 31 * result + code.contentHashCode()
+        return result
+    }
+}
+
+interface NodeState {
+    fun getNode(key: String): Node?
+
+    fun putNode(key: String, node: Node)
+
+    fun rootHash(): String
+
+    fun snapshot(): StateSnapshot
+}
--- a/app/src/main/kotlin/rip/crit/twist/state/WorldState.kt
+++ b/app/src/main/kotlin/rip/crit/twist/state/WorldState.kt
@ -0,0 +1,51 @@
+package rip.crit.twist.state
+
+import rip.crit.twist.core.Address
+import rip.crit.twist.core.Amount
+import rip.crit.twist.core.Hash
+
+data class Account(val nonce: Long = 0, val balance: Amount, val code: ByteArray = byteArrayOf()) {
+    override fun equals(other: Any?): Boolean {
+        if (this === other) return true
+        if (javaClass != other?.javaClass) return false
+
+        other as Account
+
+        if (nonce != other.nonce) return false
+        if (balance != other.balance) return false
+        if (!code.contentEquals(other.code)) return false
+
+        return true
+    }
+
+    override fun hashCode(): Int {
+        var result = nonce.hashCode()
+        result = 31 * result + balance.hashCode()
+        result = 31 * result + code.contentHashCode()
+        return result
+    }
+}
+
+interface WorldState {
+    fun account(address: Address): Account?
+
+    fun putAccount(address: Address, account: Account)
+
+    fun deleteAccount(address: Address)
+
+    fun rootHash(): Hash
+
+    fun snapshot(): StateSnapshot
+}
+
+interface ContractState : WorldState {
+    fun storage(contract: Address, key: Hash): ByteArray?
+
+    fun putStorage(contract: Address, key: Hash, value: ByteArray)
+
+    fun deleteStorage(contract: Address)
+}
+
+interface StateSnapshot : AutoCloseable {
+    override fun close()
+}
--- a/app/src/main/kotlin/rip/crit/twist/store/FileStore.kt
+++ b/app/src/main/kotlin/rip/crit/twist/store/FileStore.kt
@ -0,0 +1,108 @@
+package rip.crit.twist.store
+
+import java.math.BigInteger
+import java.nio.file.Files
+import java.nio.file.Path
+import java.util.Base64
+import rip.crit.twist.core.Address
+import rip.crit.twist.core.Amount
+import rip.crit.twist.core.Block
+import rip.crit.twist.core.BlockHeader
+import rip.crit.twist.core.Hash
+import rip.crit.twist.core.Transaction
+
+/** File-per-key store with atomic replacement and defensive copies. */
+class FileKeyValueStore(private val root: Path) : KeyValueStore {
+    init {
+        Files.createDirectories(root)
+    }
+
+    override fun get(key: ByteArray): ByteArray? =
+        root.resolve(key.encode()).takeIf(Files::exists)?.let(Files::readAllBytes)
+
+    override fun put(key: ByteArray, value: ByteArray) {
+        val target = root.resolve(key.encode())
+        val temporary = Files.createTempFile(root, "put-", ".tmp")
+        Files.write(temporary, value)
+        Files.move(
+            temporary,
+            target,
+            java.nio.file.StandardCopyOption.REPLACE_EXISTING,
+            java.nio.file.StandardCopyOption.ATOMIC_MOVE,
+        )
+    }
+
+    override fun delete(key: ByteArray) {
+        Files.deleteIfExists(root.resolve(key.encode()))
+    }
+
+    private fun ByteArray.encode(): String =
+        Base64.getUrlEncoder().withoutPadding().encodeToString(this)
+}
+
+class FileBlockStore(private val root: Path) : BlockStore {
+    init {
+        Files.createDirectories(root)
+    }
+
+    override fun get(hash: Hash): Block? =
+        root.resolve("${hash.value}.block").takeIf(Files::exists)?.let {
+            decode(Files.readAllLines(it))
+        }
+
+    override fun put(block: Block) {
+        val file = root.resolve("${block.hash.value}.block")
+        val temporary = Files.createTempFile(root, "block-", ".tmp")
+        Files.write(temporary, encode(block))
+        Files.move(
+            temporary,
+            file,
+            java.nio.file.StandardCopyOption.REPLACE_EXISTING,
+            java.nio.file.StandardCopyOption.ATOMIC_MOVE,
+        )
+    }
+
+    private fun encode(block: Block): List<String> = buildList {
+        add(block.hash.value)
+        add(block.header.parentHash.value)
+        add(block.header.stateRoot.value)
+        add(block.header.height.toString())
+        add(block.header.timestampMillis.toString())
+        add(block.transactions.size.toString())
+        block.transactions.forEach {
+            add(
+                listOf(
+                        it.id.value,
+                        it.sender.value,
+                        it.recipient?.value.orEmpty(),
+                        it.nonce,
+                        it.value.value,
+                        Base64.getEncoder().encodeToString(it.payload),
+                    )
+                    .joinToString("\t")
+            )
+        }
+    }
+
+    private fun decode(lines: List<String>): Block? = runCatching {
+        require(lines.size >= 6)
+        val header =
+            BlockHeader(Hash(lines[1]), Hash(lines[2]), lines[3].toLong(), lines[4].toLong())
+        val count = lines[5].toInt()
+        require(lines.size == 6 + count)
+        val transactions =
+            lines.drop(6).map { line ->
+                val f = line.split("\t", limit = 6)
+                Transaction(
+                    Hash(f[0]),
+                    Address(f[1]),
+                    f[2].takeIf(String::isNotEmpty)?.let(::Address),
+                    f[3].toLong(),
+                    Amount(BigInteger(f[4])),
+                    Base64.getDecoder().decode(f[5]),
+                )
+            }
+        Block(header, transactions, Hash(lines[0]))
+    }
+        .getOrNull()
+}
--- a/app/src/main/kotlin/rip/crit/twist/store/InMemoryStore.kt
+++ b/app/src/main/kotlin/rip/crit/twist/store/InMemoryStore.kt
@ -0,0 +1,31 @@
+package rip.crit.twist.store
+
+import java.util.concurrent.ConcurrentHashMap
+import rip.crit.twist.core.Block
+import rip.crit.twist.core.Hash
+
+class InMemoryBlockStore : BlockStore {
+    private val blocks = ConcurrentHashMap<Hash, Block>()
+
+    override fun get(hash: Hash): Block? = blocks[hash]
+
+    override fun put(block: Block) {
+        blocks[block.hash] = block
+    }
+}
+
+class InMemoryKeyValueStore : KeyValueStore {
+    private val values = ConcurrentHashMap<String, ByteArray>()
+
+    override fun get(key: ByteArray): ByteArray? = values[key.toKey()]?.copyOf()
+
+    override fun put(key: ByteArray, value: ByteArray) {
+        values[key.toKey()] = value.copyOf()
+    }
+
+    override fun delete(key: ByteArray) {
+        values.remove(key.toKey())
+    }
+
+    private fun ByteArray.toKey(): String = joinToString("") { "%02x".format(it) }
+}
--- a/app/src/main/kotlin/rip/crit/twist/store/Store.kt
+++ b/app/src/main/kotlin/rip/crit/twist/store/Store.kt
@ -0,0 +1,18 @@
+package rip.crit.twist.store
+
+import rip.crit.twist.core.Block
+import rip.crit.twist.core.Hash
+
+interface BlockStore {
+    fun get(hash: Hash): Block?
+
+    fun put(block: Block)
+}
+
+interface KeyValueStore {
+    fun get(key: ByteArray): ByteArray?
+
+    fun put(key: ByteArray, value: ByteArray)
+
+    fun delete(key: ByteArray)
+}
--- a/app/src/main/kotlin/rip/crit/twist/transport/AesGcm.kt
+++ b/app/src/main/kotlin/rip/crit/twist/transport/AesGcm.kt
@ -0,0 +1,227 @@
+package rip.crit.twist.transport
+
+import rip.crit.twist.core.SmartDoc
+
+/** FIPS 197 AES and SP 800-38D GCM implementation. */
+class Aes(private val key: ByteArray) {
+    private val rounds = key.size / 4 + 6
+    private val schedule: IntArray
+
+    init {
+        require(key.size in setOf(16, 24, 32))
+        schedule = expandKey(key)
+    }
+
+    fun encryptBlock(input: ByteArray): ByteArray {
+        require(input.size == 16)
+        var state = input.copyOf()
+        addRoundKey(state, 0)
+        for (round in 1 until rounds) {
+            subBytes(state)
+            state = shiftRows(state)
+            mixColumns(state)
+            addRoundKey(state, round)
+        }
+        subBytes(state)
+        state = shiftRows(state)
+        addRoundKey(state, rounds)
+        return state
+    }
+
+    private fun expandKey(key: ByteArray): IntArray {
+        val nk = key.size / 4
+        val words = IntArray(4 * (rounds + 1))
+        for (i in 0 until nk) words[i] =
+            ((key[4 * i].toInt() and 255) shl 24) or
+                ((key[4 * i + 1].toInt() and 255) shl 16) or
+                ((key[4 * i + 2].toInt() and 255) shl 8) or
+                (key[4 * i + 3].toInt() and 255)
+        var rcon = 1
+        for (i in nk until words.size) {
+            var temp = words[i - 1]
+            if (i % nk == 0) {
+                temp = subWord(temp.rotateLeft(8)) xor (rcon shl 24)
+                rcon = multiply(rcon, 2)
+            } else if (nk > 6 && i % nk == 4) temp = subWord(temp)
+            words[i] = words[i - nk] xor temp
+        }
+        return words
+    }
+
+    private fun subWord(word: Int): Int =
+        (sbox(word ushr 24) shl 24) or
+            (sbox(word ushr 16) shl 16) or
+            (sbox(word ushr 8) shl 8) or
+            sbox(word)
+
+    private fun subBytes(state: ByteArray) {
+        for (i in state.indices) state[i] = sbox(state[i].toInt()).toByte()
+    }
+
+    private fun shiftRows(s: ByteArray): ByteArray =
+        ByteArray(16).also { out ->
+            for (r in 0..3) for (c in 0..3) out[r + 4 * c] = s[r + 4 * ((c + r) % 4)]
+        }
+
+    private fun mixColumns(s: ByteArray) {
+        for (c in 0..3) {
+            val i = 4 * c
+            val a = IntArray(4) { s[i + it].toInt() and 255 }
+            s[i] = (multiply(a[0], 2) xor multiply(a[1], 3) xor a[2] xor a[3]).toByte()
+            s[i + 1] = (a[0] xor multiply(a[1], 2) xor multiply(a[2], 3) xor a[3]).toByte()
+            s[i + 2] = (a[0] xor a[1] xor multiply(a[2], 2) xor multiply(a[3], 3)).toByte()
+            s[i + 3] = (multiply(a[0], 3) xor a[1] xor a[2] xor multiply(a[3], 2)).toByte()
+        }
+    }
+
+    private fun addRoundKey(s: ByteArray, round: Int) {
+        for (c in 0..3) {
+            val w = schedule[round * 4 + c]
+            for (r in 0..3) s[4 * c + r] = (s[4 * c + r].toInt() xor (w ushr (24 - 8 * r))).toByte()
+        }
+    }
+
+    private fun sbox(value: Int): Int {
+        val x = value and 255
+        val inverse = if (x == 0) 0 else power(x, 254)
+        return (inverse xor
+            inverse.rotateByte(1) xor
+            inverse.rotateByte(2) xor
+            inverse.rotateByte(3) xor
+            inverse.rotateByte(4) xor
+            0x63) and 255
+    }
+
+    private fun Int.rotateByte(bits: Int): Int = ((this shl bits) or (this ushr (8 - bits))) and 255
+
+    private fun power(value: Int, exponent: Int): Int {
+        var base = value
+        var power = exponent
+        var result = 1
+        while (power > 0) {
+            if (power and 1 != 0) result = multiply(result, base)
+            base = multiply(base, base)
+            power = power ushr 1
+        }
+        return result
+    }
+
+    private fun multiply(left: Int, right: Int): Int {
+        var a = left
+        var b = right
+        var result = 0
+        repeat(8) {
+            if (b and 1 != 0) result = result xor a
+            a = ((a shl 1) xor if (a and 0x80 != 0) 0x11b else 0) and 255
+            b = b ushr 1
+        }
+        return result
+    }
+}
+
+data class GcmCiphertext(val ciphertext: ByteArray, val tag: ByteArray)
+
+@SmartDoc(
+    summary = "AES-GCM authenticated encryption with explicit nonces.",
+    category = "Cryptography",
+)
+class AesGcm(key: ByteArray) {
+    private val aes = Aes(key)
+
+    fun encrypt(
+        nonce: ByteArray,
+        plaintext: ByteArray,
+        aad: ByteArray = byteArrayOf(),
+    ): GcmCiphertext {
+        require(nonce.size == 12)
+        val h = aes.encryptBlock(ByteArray(16))
+        val j0 = nonce + byteArrayOf(0, 0, 0, 1)
+        val ciphertext = ctr(j0, plaintext)
+        val tag = xor(aes.encryptBlock(j0), ghash(h, aad, ciphertext))
+        return GcmCiphertext(ciphertext, tag)
+    }
+
+    fun decrypt(
+        nonce: ByteArray,
+        ciphertext: ByteArray,
+        tag: ByteArray,
+        aad: ByteArray = byteArrayOf(),
+    ): ByteArray {
+        require(tag.size == 16)
+        val result = encryptTag(nonce, ciphertext, aad)
+        require(constantEquals(tag, result)) { "GCM authentication failed" }
+        return ctr(nonce + byteArrayOf(0, 0, 0, 1), ciphertext)
+    }
+
+    private fun encryptTag(nonce: ByteArray, ciphertext: ByteArray, aad: ByteArray): ByteArray {
+        require(nonce.size == 12)
+        val h = aes.encryptBlock(ByteArray(16))
+        return xor(aes.encryptBlock(nonce + byteArrayOf(0, 0, 0, 1)), ghash(h, aad, ciphertext))
+    }
+
+    private fun ctr(j0: ByteArray, input: ByteArray): ByteArray {
+        val counter = j0.copyOf()
+        val out = ByteArray(input.size)
+        var offset = 0
+        while (offset < input.size) {
+            increment(counter)
+            val stream = aes.encryptBlock(counter)
+            val count = minOf(16, input.size - offset)
+            for (i in 0 until count) out[offset + i] =
+                (input[offset + i].toInt() xor stream[i].toInt()).toByte()
+            offset += count
+        }
+        return out
+    }
+
+    private fun increment(counter: ByteArray) {
+        for (i in 15 downTo 12) {
+            counter[i] = (counter[i] + 1).toByte()
+            if (counter[i].toInt() != 0) break
+        }
+    }
+
+    private fun ghash(h: ByteArray, aad: ByteArray, ciphertext: ByteArray): ByteArray {
+        var y = ByteArray(16)
+        for (block in blocks(aad) + blocks(ciphertext)) y = multiplyGf(xor(y, block), h)
+        val lengths = ByteArray(16)
+        writeLong(lengths, 0, aad.size.toLong() * 8)
+        writeLong(lengths, 8, ciphertext.size.toLong() * 8)
+        return multiplyGf(xor(y, lengths), h)
+    }
+
+    private fun blocks(data: ByteArray): List<ByteArray> =
+        data.asList().chunked(16).map { chunk ->
+            ByteArray(16).also { out -> chunk.forEachIndexed { i, b -> out[i] = b } }
+        }
+
+    private fun multiplyGf(x: ByteArray, y: ByteArray): ByteArray {
+        var z = ByteArray(16)
+        val v = y.copyOf()
+        for (i in 0 until 128) {
+            if ((x[i / 8].toInt() and (1 shl (7 - i % 8))) != 0)
+                for (j in 0..15) z[j] = (z[j].toInt() xor v[j].toInt()).toByte()
+            val lsb = v[15].toInt() and 1
+            for (j in 15 downTo 0) v[j] =
+                (((v[j].toInt() and 255) ushr 1) or
+                        if (j > 0) ((v[j - 1].toInt() and 1) shl 7) else 0)
+                    .toByte()
+            if (lsb != 0) v[0] = (v[0].toInt() xor 0xe1).toByte()
+        }
+        return z
+    }
+
+    private fun xor(a: ByteArray, b: ByteArray) =
+        ByteArray(a.size) { (a[it].toInt() xor b[it].toInt()).toByte() }
+
+    private fun writeLong(out: ByteArray, offset: Int, value: Long) {
+        for (i in 0..7) out[offset + i] = (value ushr (56 - 8 * i)).toByte()
+    }
+
+    private fun constantEquals(a: ByteArray, b: ByteArray): Boolean {
+        if (a.size != b.size) return false
+        var d = 0
+        for (i in a.indices) d = d or (a[i].toInt() xor b[i].toInt())
+        return d == 0
+    }
+}
--- a/app/src/main/kotlin/rip/crit/twist/transport/SecureTransport.kt
+++ b/app/src/main/kotlin/rip/crit/twist/transport/SecureTransport.kt
@ -0,0 +1,67 @@
+package rip.crit.twist.transport
+
+import java.io.DataInputStream
+import java.io.DataOutputStream
+import java.net.Socket
+import kotlin.random.Random
+import rip.crit.twist.core.HmacSha256
+import rip.crit.twist.wire.FrameCodec
+import rip.crit.twist.wire.PacketCodec
+import rip.crit.twist.wire.WirePacket
+
+data class X25519KeyPair(val privateKey: ByteArray, val publicKey: ByteArray)
+
+/** X25519 key agreement with HKDF-SHA256 and AES-GCM. */
+class X25519Session private constructor(private val key: ByteArray) {
+    fun encrypt(plain: ByteArray, nonce: ByteArray): ByteArray {
+        val encrypted = AesGcm(key).encrypt(nonce, plain)
+        return encrypted.ciphertext + encrypted.tag
+    }
+
+    fun decrypt(ciphertext: ByteArray, nonce: ByteArray): ByteArray {
+        require(ciphertext.size >= 16)
+        return AesGcm(key)
+            .decrypt(
+                nonce,
+                ciphertext.copyOfRange(0, ciphertext.size - 16),
+                ciphertext.copyOfRange(ciphertext.size - 16, ciphertext.size),
+            )
+    }
+
+    companion object {
+        fun generateKeyPair(random: Random = Random.Default): X25519KeyPair {
+            val privateKey = random.nextBytes(32)
+            return X25519KeyPair(privateKey, X25519.publicKey(privateKey))
+        }
+
+        fun establish(
+            privateKey: ByteArray,
+            remotePublicKey: ByteArray,
+            context: ByteArray = "twist-v1".encodeToByteArray(),
+        ): X25519Session {
+            val secret = X25519.sharedSecret(privateKey, remotePublicKey)
+            val prk = HmacSha256.digest(ByteArray(32), secret)
+            return X25519Session(HmacSha256.digest(prk, context + byteArrayOf(1)))
+        }
+    }
+}
+
+/** Blocking TCP transport, suitable for adapters and integration tests. */
+class TcpPacketTransport(private val socket: Socket) : AutoCloseable {
+    private val input = DataInputStream(socket.getInputStream())
+    private val output = DataOutputStream(socket.getOutputStream())
+
+    fun send(packet: WirePacket) {
+        val frame = FrameCodec.encode(PacketCodec.encode(packet))
+        output.write(frame)
+        output.flush()
+    }
+
+    fun receive(): WirePacket {
+        val size = input.readInt()
+        require(size in 0..FrameCodec.MAX_FRAME_SIZE)
+        return PacketCodec.decode(input.readNBytes(size))
+    }
+
+    override fun close() = socket.close()
+}
--- a/app/src/main/kotlin/rip/crit/twist/transport/TcpPeerNetwork.kt
+++ b/app/src/main/kotlin/rip/crit/twist/transport/TcpPeerNetwork.kt
@ -0,0 +1,122 @@
+package rip.crit.twist.transport
+
+import java.io.DataInputStream
+import java.io.DataOutputStream
+import java.net.InetSocketAddress
+import java.net.ServerSocket
+import java.net.Socket
+import java.util.concurrent.ConcurrentHashMap
+import java.util.concurrent.CopyOnWriteArrayList
+import java.util.concurrent.Executors
+import java.util.concurrent.atomic.AtomicBoolean
+import rip.crit.twist.core.SmartDoc
+import rip.crit.twist.p2p.EnvelopeAdapter
+import rip.crit.twist.p2p.NetworkAdapter
+import rip.crit.twist.p2p.NetworkAdapterKind
+import rip.crit.twist.p2p.NetworkMessage
+import rip.crit.twist.p2p.PeerId
+import rip.crit.twist.p2p.PeerNetwork
+import rip.crit.twist.wire.FrameCodec
+
+/** Basic TCP peer network with framed messages and an explicit adapter boundary. */
+@SmartDoc(
+    summary = "TCP peer listener, handshake, and broadcast transport.",
+    category = "Networking",
+)
+class TcpPeerNetwork(
+    private val localId: PeerId,
+    private val requestedPort: Int = 0,
+    private val adapter: NetworkAdapter = EnvelopeAdapter(NetworkAdapterKind.DEVP2P),
+) : PeerNetwork {
+    private val running = AtomicBoolean(false)
+    private val connections = ConcurrentHashMap<PeerId, Connection>()
+    private val listeners = CopyOnWriteArrayList<(NetworkMessage) -> Unit>()
+    private val workers = Executors.newCachedThreadPool()
+    private var server: ServerSocket? = null
+
+    val port: Int
+        get() = server?.localPort ?: -1
+
+    override fun start() {
+        if (!running.compareAndSet(false, true)) return
+        server = ServerSocket(requestedPort)
+        workers.execute {
+            while (running.get()) {
+                runCatching { server?.accept() }.getOrNull()?.let(::attach)
+            }
+        }
+    }
+
+    fun connect(host: String, port: Int, timeoutMillis: Int = 5_000) {
+        check(running.get()) { "Network is not running" }
+        val socket = Socket()
+        socket.connect(InetSocketAddress(host, port), timeoutMillis)
+        attach(socket)
+    }
+
+    fun subscribe(listener: (NetworkMessage) -> Unit) {
+        listeners += listener
+    }
+
+    override fun stop() {
+        if (!running.compareAndSet(true, false)) return
+        runCatching { server?.close() }
+        connections.values.forEach { it.close() }
+        connections.clear()
+        workers.shutdownNow()
+    }
+
+    override fun peers(): Set<PeerId> = connections.keys.toSet()
+
+    override fun broadcast(message: NetworkMessage) {
+        check(running.get()) { "Network is not running" }
+        connections.values.forEach { connection -> runCatching { connection.send(message) } }
+    }
+
+    private fun attach(socket: Socket) {
+        workers.execute {
+            val input = DataInputStream(socket.getInputStream())
+            val output = DataOutputStream(socket.getOutputStream())
+            output.writeUTF(localId.value)
+            output.flush()
+            val remote = PeerId(input.readUTF())
+            require(remote != localId) { "Self connection is not allowed" }
+            val connection = Connection(socket, input, output)
+            val previous = connections.put(remote, connection)
+            previous?.close()
+            try {
+                while (running.get() && !socket.isClosed) {
+                    val size = input.readInt()
+                    require(size in 0..FrameCodec.MAX_FRAME_SIZE) { "Invalid network frame length" }
+                    val frame = ByteArray(size).also(input::readFully)
+                    val message = adapter.decode(frame)
+                    listeners.forEach { listener -> listener(message) }
+                }
+            } finally {
+                connections.remove(remote, connection)
+                connection.close()
+            }
+        }
+    }
+
+    private inner class Connection(
+        private val socket: Socket,
+        private val input: DataInputStream,
+        private val output: DataOutputStream,
+    ) {
+        @Synchronized
+        fun send(message: NetworkMessage) {
+            val frame = adapter.encode(message)
+            require(frame.size <= FrameCodec.MAX_FRAME_SIZE)
+            output.writeInt(frame.size)
+            output.write(frame)
+            output.flush()
+        }
+
+        fun close() {
+            runCatching { input.close() }
+            runCatching { output.close() }
+            runCatching { socket.close() }
+        }
+    }
+}
--- a/app/src/main/kotlin/rip/crit/twist/transport/TwistOverlayAdapter.kt
+++ b/app/src/main/kotlin/rip/crit/twist/transport/TwistOverlayAdapter.kt
@ -0,0 +1,36 @@
+package rip.crit.twist.transport
+
+import kotlin.random.Random
+import rip.crit.twist.core.TwistSpecific
+import rip.crit.twist.p2p.EnvelopeAdapter
+import rip.crit.twist.p2p.NetworkAdapterKind
+import rip.crit.twist.p2p.NetworkMessage
+
+/** Twist overlay protected by the bundled AES-GCM implementation. */
+class TwistOverlayAdapter(
+    @Suppress("UNUSED_PARAMETER") twistSpecific: TwistSpecific.Enabled,
+    private val key: ByteArray,
+    private val random: Random = Random.Default,
+) : EnvelopeAdapter(NetworkAdapterKind.TWIST_OVERLAY) {
+    init {
+        require(key.size == 32)
+    }
+
+    override fun encode(message: NetworkMessage): ByteArray {
+        val nonce = random.nextBytes(12)
+        val encrypted = AesGcm(key).encrypt(nonce, super.encode(message))
+        return nonce + encrypted.ciphertext + encrypted.tag
+    }
+
+    override fun decode(frame: ByteArray): NetworkMessage {
+        require(frame.size > 28)
+        val plain =
+            AesGcm(key)
+                .decrypt(
+                    frame.copyOfRange(0, 12),
+                    frame.copyOfRange(12, frame.size - 16),
+                    frame.copyOfRange(frame.size - 16, frame.size),
+                )
+        return super.decode(plain)
+    }
+}
--- a/app/src/main/kotlin/rip/crit/twist/transport/X25519.kt
+++ b/app/src/main/kotlin/rip/crit/twist/transport/X25519.kt
@ -0,0 +1,84 @@
+package rip.crit.twist.transport
+
+import java.math.BigInteger
+import rip.crit.twist.core.SmartDoc
+
+/** RFC 7748 X25519 implementation using readable BigInteger field arithmetic. */
+@SmartDoc(summary = "RFC 7748 X25519 key agreement primitives.", category = "Cryptography")
+object X25519 {
+    private val prime = BigInteger.ONE.shiftLeft(255) - BigInteger.valueOf(19)
+    private val a24 = BigInteger.valueOf(121665)
+
+    private fun mod(value: BigInteger): BigInteger = value.mod(prime)
+
+    fun publicKey(privateKey: ByteArray): ByteArray =
+        scalarMult(privateKey, byteArrayOf(9) + ByteArray(31))
+
+    fun sharedSecret(privateKey: ByteArray, publicKey: ByteArray): ByteArray =
+        scalarMult(privateKey, publicKey).also {
+            require(it.any { byte -> byte.toInt() != 0 }) {
+                "X25519 rejected an all-zero shared secret"
+            }
+        }
+
+    fun scalarMult(privateKey: ByteArray, uCoordinate: ByteArray): ByteArray {
+        require(privateKey.size == 32 && uCoordinate.size == 32)
+        val scalarBytes =
+            privateKey.copyOf().also {
+                it[0] = (it[0].toInt() and 248).toByte()
+                it[31] = ((it[31].toInt() and 127) or 64).toByte()
+            }
+        val uBytes = uCoordinate.copyOf().also { it[31] = (it[31].toInt() and 127).toByte() }
+        val scalar = littleEndian(scalarBytes)
+        val x1 = littleEndian(uBytes).mod(prime)
+        var x2 = BigInteger.ONE
+        var z2 = BigInteger.ZERO
+        var x3 = x1
+        var z3 = BigInteger.ONE
+        var swap = 0
+        for (position in 254 downTo 0) {
+            val bit = if (scalar.testBit(position)) 1 else 0
+            swap = swap xor bit
+            if (swap != 0) {
+                val tx = x2
+                x2 = x3
+                x3 = tx
+                val tz = z2
+                z2 = z3
+                z3 = tz
+            }
+            swap = bit
+            val a = mod(x2 + z2)
+            val aa = mod(a * a)
+            val b = mod(x2 - z2)
+            val bb = mod(b * b)
+            val e = mod(aa - bb)
+            val c = mod(x3 + z3)
+            val d = mod(x3 - z3)
+            val da = mod(d * a)
+            val cb = mod(c * b)
+            x3 = mod((da + cb).pow(2))
+            z3 = mod(x1 * mod((da - cb).pow(2)))
+            x2 = mod(aa * bb)
+            z2 = mod(e * mod(aa + a24 * e))
+        }
+        if (swap != 0) {
+            val tx = x2
+            x2 = x3
+            x3 = tx
+            val tz = z2
+            z2 = z3
+            z3 = tz
+        }
+        return encodeLittleEndian(mod(x2 * z2.modInverse(prime)))
+    }
+
+    private fun littleEndian(bytes: ByteArray): BigInteger = BigInteger(1, bytes.reversedArray())
+
+    private fun encodeLittleEndian(value: BigInteger): ByteArray {
+        val source = value.toByteArray().dropWhile { it == 0.toByte() }.reversed()
+        return ByteArray(32).also { output ->
+            source.take(32).forEachIndexed { index, byte -> output[index] = byte }
+        }
+    }
+}
--- a/app/src/main/kotlin/rip/crit/twist/tvm/BytecodeVirtualMachine.kt
+++ b/app/src/main/kotlin/rip/crit/twist/tvm/BytecodeVirtualMachine.kt
@ -0,0 +1,249 @@
+package rip.crit.twist.tvm
+
+import java.math.BigInteger
+import rip.crit.twist.bytecode.OpCode
+import rip.crit.twist.bytecode.TwistBytecode
+import rip.crit.twist.core.Address
+import rip.crit.twist.core.Amount
+import rip.crit.twist.core.Sha256
+import rip.crit.twist.core.SmartDoc
+import rip.crit.twist.core.Transaction
+import rip.crit.twist.gas.BasicGasMeter
+import rip.crit.twist.gas.GasLimit
+import rip.crit.twist.state.ContractState
+import rip.crit.twist.state.InMemoryWorldState
+import rip.crit.twist.state.WorldState
+
+/** Minimal deterministic stack VM for the Phase 3 instruction set. */
+@SmartDoc(
+    summary = "Deterministic 256-bit stack virtual machine with metered execution.",
+    category = "Execution",
+)
+class BytecodeVirtualMachine(private val gasLimit: GasLimit = GasLimit(1_000_000)) :
+    VirtualMachine {
+    override fun execute(transaction: Transaction, state: WorldState): ExecutionResult {
+        if (state !is ContractState)
+            return ExecutionResult(
+                false,
+                rip.crit.twist.gas.GasUsed(0),
+                error = "ContractState is required",
+            )
+        val context =
+            ExecutionContext(
+                transaction.recipient ?: transaction.sender,
+                transaction.sender,
+                transaction.value,
+            )
+        return execute(transaction.payload, byteArrayOf(), StateExecutionHost(context, state))
+    }
+
+    fun execute(code: ByteArray, input: ByteArray, contract: Address): ExecutionResult =
+        execute(
+            code,
+            input,
+            StateExecutionHost(
+                ExecutionContext(contract, contract, Amount(BigInteger.ZERO)),
+                InMemoryWorldState(),
+            ),
+        )
+
+    fun execute(code: ByteArray, input: ByteArray, host: ExecutionHost): ExecutionResult {
+        val meter = BasicGasMeter(gasLimit)
+        return try {
+            val instructions = TwistBytecode.decode(code)
+            val stack = ArrayDeque<Word256>()
+            val calldata = Calldata.wrap(input)
+            val transient = TransientStorage()
+            val memory = LinearMemory()
+            var pc = 0
+            while (pc in instructions.indices) {
+                val instruction = instructions[pc]
+                meter.consume(1)
+                when (instruction.opCode) {
+                    OpCode.STOP ->
+                        return ExecutionResult(
+                            true,
+                            meter.used,
+                            stack.lastOrNull()?.toBytes() ?: byteArrayOf(),
+                        )
+                    OpCode.PUSH32 -> stack.addLast(Word256.fromBytes(instruction.immediate))
+                    OpCode.ADD -> stack.addLast(stack.removeLast() + stack.removeLast())
+                    OpCode.SUB -> {
+                        val right = stack.removeLast()
+                        stack.addLast(stack.removeLast() - right)
+                    }
+                    OpCode.MUL -> stack.addLast(stack.removeLast() * stack.removeLast())
+                    OpCode.DIV -> {
+                        val right = stack.removeLast()
+                        stack.addLast(stack.removeLast() / right)
+                    }
+                    OpCode.EQ ->
+                        stack.addLast(booleanWord(stack.removeLast() == stack.removeLast()))
+                    OpCode.LT -> {
+                        val right = stack.removeLast()
+                        stack.addLast(booleanWord(stack.removeLast() < right))
+                    }
+                    OpCode.GT -> {
+                        val right = stack.removeLast()
+                        stack.addLast(booleanWord(stack.removeLast() > right))
+                    }
+                    OpCode.AND -> stack.addLast(stack.removeLast() and stack.removeLast())
+                    OpCode.OR -> stack.addLast(stack.removeLast() or stack.removeLast())
+                    OpCode.NOT -> stack.addLast(stack.removeLast().inv())
+                    OpCode.DUP -> stack.addLast(stack.last())
+                    OpCode.SWAP -> {
+                        val a = stack.removeLast()
+                        val b = stack.removeLast()
+                        stack.addLast(a)
+                        stack.addLast(b)
+                    }
+                    OpCode.CALLDATA_LOAD -> {
+                        val offset = stack.removeLast().toBigInteger().intValueExact()
+                        stack.addLast(calldata.wordAt(offset))
+                    }
+                    OpCode.TLOAD ->
+                        stack.addLast(transient.get(host.context.contract, stack.removeLast()))
+                    OpCode.TSTORE -> {
+                        val value = stack.removeLast()
+                        transient.put(host.context.contract, stack.removeLast(), value)
+                    }
+                    OpCode.SLOAD -> stack.addLast(host.load(stack.removeLast()))
+                    OpCode.SSTORE -> {
+                        val value = stack.removeLast()
+                        host.store(stack.removeLast(), value)
+                    }
+                    OpCode.CALLER ->
+                        stack.addLast(
+                            Word256.fromBytes(
+                                Sha256.bytes(host.context.caller.value.encodeToByteArray())
+                            )
+                        )
+                    OpCode.CALLVALUE -> stack.addLast(Word256.of(host.context.value.value))
+                    OpCode.TIMESTAMP ->
+                        stack.addLast(Word256.fromLong(host.context.timestampMillis))
+                    OpCode.BLOCK_NUMBER -> stack.addLast(Word256.fromLong(host.context.blockNumber))
+                    OpCode.BALANCE ->
+                        stack.addLast(
+                            Word256.of(
+                                host.balance(Address(stack.removeLast().toBytes().hex())).value
+                            )
+                        )
+                    OpCode.SHA256 ->
+                        stack.addLast(Word256.fromBytes(Sha256.bytes(stack.removeLast().toBytes())))
+                    OpCode.MOD -> {
+                        val right = stack.removeLast()
+                        stack.addLast(stack.removeLast() % right)
+                    }
+                    OpCode.XOR -> stack.addLast(stack.removeLast() xor stack.removeLast())
+                    OpCode.ISZERO -> stack.addLast(booleanWord(stack.removeLast() == Word256.ZERO))
+                    OpCode.POP -> stack.removeLast()
+                    OpCode.SHL -> {
+                        val bits = stack.removeLast().toBigInteger().intValueExact()
+                        stack.addLast(stack.removeLast().shiftLeft(bits))
+                    }
+                    OpCode.SHR -> {
+                        val bits = stack.removeLast().toBigInteger().intValueExact()
+                        stack.addLast(stack.removeLast().shiftRight(bits))
+                    }
+                    OpCode.BYTE -> {
+                        val index = stack.removeLast().toBigInteger().intValueExact()
+                        stack.addLast(stack.removeLast().byte(index))
+                    }
+                    OpCode.MLOAD ->
+                        stack.addLast(
+                            Word256.fromBytes(
+                                memory.load(stack.removeLast().toBigInteger().intValueExact(), 32)
+                            )
+                        )
+                    OpCode.MSTORE -> {
+                        val value = stack.removeLast()
+                        val offset = stack.removeLast().toBigInteger().intValueExact()
+                        memory.store(offset, value.toBytes())
+                    }
+                    OpCode.MSIZE -> stack.addLast(Word256.fromLong(memory.size.toLong()))
+                    OpCode.CALLDATA_SIZE -> stack.addLast(Word256.fromLong(calldata.size.toLong()))
+                    OpCode.CODE_SIZE -> stack.addLast(Word256.fromLong(code.size.toLong()))
+                    OpCode.GAS -> stack.addLast(Word256.fromLong(gasLimit.value - meter.used.value))
+                    OpCode.ADDRESS -> stack.addLast(addressWord(host.context.contract))
+                    OpCode.ORIGIN -> stack.addLast(addressWord(host.context.origin))
+                    OpCode.CHAIN_ID -> stack.addLast(Word256.fromLong(host.context.chainId))
+                    OpCode.LOG -> {
+                        val data = stack.removeLast()
+                        host.log(stack.removeLast(), data)
+                    }
+                    OpCode.CALL -> {
+                        val address = Address(stack.removeLast().toBytes().hex())
+                        stack.addLast(
+                            Word256.fromBytes(Sha256.bytes(host.call(address, byteArrayOf())))
+                        )
+                    }
+                    OpCode.JUMP -> {
+                        pc = stack.removeLast().toBigInteger().intValueExact()
+                        require(pc in instructions.indices)
+                        continue
+                    }
+                    OpCode.JUMPI -> {
+                        val target = stack.removeLast().toBigInteger().intValueExact()
+                        if (stack.removeLast() != Word256.ZERO) {
+                            pc = target
+                            require(pc in instructions.indices)
+                            continue
+                        }
+                    }
+                    OpCode.RETURN ->
+                        return ExecutionResult(
+                            true,
+                            meter.used,
+                            stack.lastOrNull()?.toBytes() ?: byteArrayOf(),
+                        )
+                    OpCode.REVERT ->
+                        return ExecutionResult(false, meter.used, error = "Execution reverted")
+                    OpCode.CREATE -> {
+                        val value = Amount(stack.removeLast().toBigInteger())
+                        val created = host.create(stack.removeLast().toBytes(), value)
+                        stack.addLast(addressWord(created))
+                    }
+                    OpCode.SELFDESTRUCT -> {
+                        host.selfDestruct(Address(stack.removeLast().toBytes().hex()))
+                        return ExecutionResult(true, meter.used)
+                    }
+                    OpCode.INVALID -> error("Invalid opcode")
+                }
+                pc++
+            }
+            ExecutionResult(true, meter.used, stack.lastOrNull()?.toBytes() ?: byteArrayOf())
+        } catch (error: Exception) {
+            ExecutionResult(false, meter.used, error = error.message)
+        }
+    }
+
+    private fun booleanWord(value: Boolean): Word256 =
+        if (value) Word256.fromLong(1) else Word256.ZERO
+
+    private fun addressWord(address: Address): Word256 =
+        Word256.fromBytes(Sha256.bytes(address.value.encodeToByteArray()))
+
+    private fun ByteArray.hex(): String = joinToString("") { "%02x".format(it) }
+}
+
+/** Expand-on-write memory with a fixed safety ceiling. */
+private class LinearMemory(private val maximumSize: Int = 16 * 1024 * 1024) {
+    private var bytes = ByteArray(0)
+    val size: Int
+        get() = bytes.size
+
+    fun load(offset: Int, length: Int): ByteArray {
+        require(offset >= 0 && length >= 0 && offset <= maximumSize - length)
+        val output = ByteArray(length)
+        if (offset < bytes.size)
+            bytes.copyInto(output, 0, offset, minOf(bytes.size, offset + length))
+        return output
+    }
+
+    fun store(offset: Int, value: ByteArray) {
+        require(offset >= 0 && offset <= maximumSize - value.size)
+        val required = offset + value.size
+        if (required > bytes.size) bytes = bytes.copyOf(required)
+        value.copyInto(bytes, offset)
+    }
+}
--- a/app/src/main/kotlin/rip/crit/twist/tvm/ExecutionHost.kt
+++ b/app/src/main/kotlin/rip/crit/twist/tvm/ExecutionHost.kt
@ -0,0 +1,119 @@
+package rip.crit.twist.tvm
+
+import java.math.BigInteger
+import rip.crit.twist.core.Address
+import rip.crit.twist.core.Amount
+import rip.crit.twist.core.Hash
+import rip.crit.twist.core.Sha256
+import rip.crit.twist.state.ContractState
+
+data class ExecutionContext(
+    val contract: Address,
+    val caller: Address,
+    val value: Amount,
+    val blockNumber: Long = 0,
+    val timestampMillis: Long = 0,
+    val origin: Address = caller,
+    val chainId: Long = 1,
+    val callDepth: Int = 0,
+)
+
+data class ContractLog(val contract: Address, val topic: Word256, val data: Word256)
+
+interface ExecutionHost {
+    val context: ExecutionContext
+
+    fun load(key: Word256): Word256
+
+    fun store(key: Word256, value: Word256)
+
+    fun balance(address: Address): Amount
+
+    fun log(topic: Word256, data: Word256)
+
+    fun call(address: Address, input: ByteArray): ByteArray
+
+    fun create(code: ByteArray, value: Amount): Address
+
+    fun selfDestruct(beneficiary: Address)
+}
+
+class StateExecutionHost(override val context: ExecutionContext, private val state: ContractState) :
+    ExecutionHost {
+    val logs = mutableListOf<ContractLog>()
+
+    override fun load(key: Word256): Word256 =
+        state.storage(context.contract, Hash(key.toBytes().hex()))?.let(Word256::fromBytes)
+            ?: Word256.ZERO
+
+    override fun store(key: Word256, value: Word256) =
+        state.putStorage(context.contract, Hash(key.toBytes().hex()), value.toBytes())
+
+    override fun balance(address: Address): Amount =
+        state.account(address)?.balance ?: Amount(BigInteger.ZERO)
+
+    override fun log(topic: Word256, data: Word256) {
+        logs += ContractLog(context.contract, topic, data)
+    }
+
+    override fun call(address: Address, input: ByteArray): ByteArray {
+        require(context.callDepth < MAX_CALL_DEPTH) { "Maximum call depth exceeded" }
+        val code = state.account(address)?.code ?: return byteArrayOf()
+        val child =
+            StateExecutionHost(
+                context.copy(
+                    contract = address,
+                    caller = context.contract,
+                    value = Amount(BigInteger.ZERO),
+                    callDepth = context.callDepth + 1,
+                ),
+                state,
+            )
+        val result = BytecodeVirtualMachine().execute(code, input, child)
+        require(result.succeeded) { result.error ?: "Nested call failed" }
+        logs += child.logs
+        return result.returnData
+    }
+
+    override fun create(code: ByteArray, value: Amount): Address {
+        val creator = state.account(context.contract)
+        require(value.value <= (creator?.balance?.value ?: BigInteger.ZERO)) {
+            "Insufficient creation balance"
+        }
+        val seed =
+            context.contract.value.encodeToByteArray() +
+                (creator?.nonce ?: 0).toString().encodeToByteArray() +
+                code
+        val address = Address(Sha256.digest(seed).value.takeLast(40))
+        require(state.account(address) == null) { "Contract address collision" }
+        if (creator != null) {
+            state.putAccount(
+                context.contract,
+                creator.copy(
+                    nonce = creator.nonce + 1,
+                    balance = Amount(creator.balance.value - value.value),
+                ),
+            )
+        }
+        state.putAccount(address, rip.crit.twist.state.Account(balance = value, code = code))
+        return address
+    }
+
+    override fun selfDestruct(beneficiary: Address) {
+        val account = state.account(context.contract) ?: return
+        val recipient =
+            state.account(beneficiary)
+                ?: rip.crit.twist.state.Account(balance = Amount(BigInteger.ZERO))
+        state.putAccount(
+            beneficiary,
+            recipient.copy(balance = Amount(recipient.balance.value + account.balance.value)),
+        )
+        state.deleteAccount(context.contract)
+    }
+
+    private fun ByteArray.hex() = joinToString("") { "%02x".format(it) }
+
+    private companion object {
+        const val MAX_CALL_DEPTH = 64
+    }
+}
--- a/app/src/main/kotlin/rip/crit/twist/tvm/TransientStorage.kt
+++ b/app/src/main/kotlin/rip/crit/twist/tvm/TransientStorage.kt
@ -0,0 +1,16 @@
+package rip.crit.twist.tvm
+
+import java.util.concurrent.ConcurrentHashMap
+import rip.crit.twist.core.Address
+
+class TransientStorage {
+    private val values = ConcurrentHashMap<Address, ConcurrentHashMap<Word256, Word256>>()
+
+    fun get(contract: Address, key: Word256): Word256 = values[contract]?.get(key) ?: Word256.ZERO
+
+    fun put(contract: Address, key: Word256, value: Word256) {
+        values.computeIfAbsent(contract) { ConcurrentHashMap() }[key] = value
+    }
+
+    fun clear() = values.clear()
+}
--- a/app/src/main/kotlin/rip/crit/twist/tvm/VirtualMachine.kt
+++ b/app/src/main/kotlin/rip/crit/twist/tvm/VirtualMachine.kt
@ -0,0 +1,38 @@
+package rip.crit.twist.tvm
+
+import rip.crit.twist.core.Transaction
+import rip.crit.twist.gas.GasUsed
+import rip.crit.twist.state.WorldState
+
+data class ExecutionResult(
+    val succeeded: Boolean,
+    val gasUsed: GasUsed,
+    val returnData: ByteArray = byteArrayOf(),
+    val error: String? = null,
+) {
+    override fun equals(other: Any?): Boolean {
+        if (this === other) return true
+        if (javaClass != other?.javaClass) return false
+
+        other as ExecutionResult
+
+        if (succeeded != other.succeeded) return false
+        if (gasUsed != other.gasUsed) return false
+        if (!returnData.contentEquals(other.returnData)) return false
+        if (error != other.error) return false
+
+        return true
+    }
+
+    override fun hashCode(): Int {
+        var result = succeeded.hashCode()
+        result = 31 * result + gasUsed.hashCode()
+        result = 31 * result + returnData.contentHashCode()
+        result = 31 * result + error.hashCode()
+        return result
+    }
+}
+
+interface VirtualMachine {
+    fun execute(transaction: Transaction, state: WorldState): ExecutionResult
+}
--- a/app/src/main/kotlin/rip/crit/twist/tvm/Word256.kt
+++ b/app/src/main/kotlin/rip/crit/twist/tvm/Word256.kt
@ -0,0 +1,88 @@
+package rip.crit.twist.tvm
+
+import java.math.BigInteger
+import java.nio.ByteBuffer
+
+/** Unsigned EVM-style integer with modulo 2^256 arithmetic. */
+@JvmInline
+value class Word256 private constructor(private val raw: BigInteger) : Comparable<Word256> {
+    operator fun plus(other: Word256): Word256 = of(raw + other.raw)
+
+    operator fun minus(other: Word256): Word256 = of(raw - other.raw)
+
+    operator fun times(other: Word256): Word256 = of(raw * other.raw)
+
+    operator fun div(other: Word256): Word256 = if (other == ZERO) ZERO else of(raw / other.raw)
+
+    operator fun rem(other: Word256): Word256 = if (other == ZERO) ZERO else of(raw % other.raw)
+
+    infix fun and(other: Word256): Word256 = of(raw.and(other.raw))
+
+    infix fun or(other: Word256): Word256 = of(raw.or(other.raw))
+
+    infix fun xor(other: Word256): Word256 = of(raw.xor(other.raw))
+
+    fun inv(): Word256 = of(raw.xor(MODULUS - BigInteger.ONE))
+
+    fun shiftLeft(bits: Int): Word256 = if (bits >= 256) ZERO else of(raw.shiftLeft(bits))
+
+    fun shiftRight(bits: Int): Word256 = if (bits >= 256) ZERO else of(raw.shiftRight(bits))
+
+    fun byte(index: Int): Word256 =
+        if (index !in 0 until BYTE_SIZE) ZERO else fromLong(toBytes()[index].toLong() and 0xff)
+
+    fun toBigInteger(): BigInteger = raw
+
+    fun toBytes(): ByteArray =
+        raw.toByteArray().let { source ->
+            ByteArray(BYTE_SIZE).also { target ->
+                source.copyInto(
+                    target,
+                    BYTE_SIZE - source.size.coerceAtMost(BYTE_SIZE),
+                    (source.size - BYTE_SIZE).coerceAtLeast(0),
+                )
+            }
+        }
+
+    override fun compareTo(other: Word256): Int = raw.compareTo(other.raw)
+
+    companion object {
+        const val BYTE_SIZE = 32
+        private val MODULUS = BigInteger.ONE.shiftLeft(256)
+        val ZERO = Word256(BigInteger.ZERO)
+
+        fun of(value: BigInteger): Word256 = Word256(value.mod(MODULUS))
+
+        fun fromBytes(bytes: ByteArray): Word256 {
+            require(bytes.size <= BYTE_SIZE)
+            return of(BigInteger(1, bytes))
+        }
+
+        fun fromLong(value: Long): Word256 {
+            require(value >= 0)
+            return of(BigInteger.valueOf(value))
+        }
+    }
+}
+
+/** Read-only calldata view. Its slices share the original byte buffer. */
+class Calldata private constructor(private val buffer: ByteBuffer) {
+    val size: Int
+        get() = buffer.capacity()
+
+    fun wordAt(offset: Int): Word256 {
+        require(offset >= 0 && offset + Word256.BYTE_SIZE <= size)
+        val bytes = ByteArray(Word256.BYTE_SIZE)
+        buffer.duplicate().position(offset).get(bytes)
+        return Word256.fromBytes(bytes)
+    }
+
+    fun slice(offset: Int, length: Int): ByteBuffer {
+        require(offset >= 0 && length >= 0 && offset + length <= size)
+        return buffer.duplicate().position(offset).limit(offset + length).slice().asReadOnlyBuffer()
+    }
+
+    companion object {
+        fun wrap(bytes: ByteArray): Calldata = Calldata(ByteBuffer.wrap(bytes).asReadOnlyBuffer())
+    }
+}
--- a/app/src/main/kotlin/rip/crit/twist/twisto/TwistoToken.kt
+++ b/app/src/main/kotlin/rip/crit/twist/twisto/TwistoToken.kt
@ -0,0 +1,138 @@
+package rip.crit.twist.twisto
+
+import java.math.BigInteger
+import rip.crit.twist.bips.StorageContract
+import rip.crit.twist.compiler.AccessOperation
+import rip.crit.twist.compiler.ContractIr
+import rip.crit.twist.compiler.contract
+import rip.crit.twist.core.Address
+import rip.crit.twist.core.Amount
+import rip.crit.twist.core.Hash
+import rip.crit.twist.core.SmartDoc
+import rip.crit.twist.standards.PersistentToken
+import rip.crit.twist.standards.TokenStandard
+import rip.crit.twist.store.KeyValueStore
+
+data class TwistoMetadata(
+    val schema: String = "twisto-metadata/1",
+    val name: String = "Twisto",
+    val symbol: String = "TWISTO",
+    val description: String,
+    val image: String? = null,
+    val externalUrl: String? = null,
+    val issuerDid: String? = null,
+    val attributes: Map<String, String> = emptyMap(),
+) {
+    init {
+        require(schema == "twisto-metadata/1")
+        require(name.isNotBlank() && name.length <= 128)
+        require(symbol.matches(Regex("[A-Z0-9]{2,12}")))
+        require(description.length <= 4_096)
+        require(
+            attributes.size <= 64 &&
+                attributes.all { it.key.length <= 64 && it.value.length <= 512 }
+        )
+    }
+
+    /** Canonical JSON manifest, suitable for content addressing. */
+    fun encode(): ByteArray = buildString {
+        append("{\"schema\":\"")
+        append(schema.escape())
+        append("\",\"name\":\"")
+        append(name.escape())
+        append("\",\"symbol\":\"")
+        append(symbol.escape())
+        append("\",\"description\":\"")
+        append(description.escape())
+        append("\",\"image\":")
+        appendJson(image)
+        append(",\"externalUrl\":")
+        appendJson(externalUrl)
+        append(",\"issuerDid\":")
+        appendJson(issuerDid)
+        append(",\"attributes\":{")
+        append(
+            attributes.toSortedMap().entries.joinToString(",") {
+                "\"${it.key.escape()}\":\"${it.value.escape()}\""
+            }
+        )
+        append("}}")
+    }
+        .encodeToByteArray()
+
+    private fun String.escape(): String =
+        replace("\\", "\\\\").replace("\"", "\\\"").replace("\n", "\\n")
+
+    private fun StringBuilder.appendJson(value: String?) {
+        if (value == null) append("null") else append("\"").append(value.escape()).append("\"")
+    }
+}
+
+/** Named token example whose immutable metadata is addressed through decentralized storage. */
+@SmartDoc(summary = "Named token with immutable decentralized metadata.", category = "Contracts")
+class TwistoToken(
+    private val owner: Address,
+    private val state: KeyValueStore,
+    private val content: StorageContract,
+) : TokenStandard {
+    private val token = PersistentToken(SYMBOL, state)
+    override val symbol: String = SYMBOL
+
+    fun deploy(metadata: TwistoMetadata, initialSupply: Amount): Hash =
+        synchronized(this) {
+            check(state.get(DEPLOYED) == null) { "Twisto is already deployed" }
+            require(metadata.symbol == SYMBOL)
+            val pointer = content.put(metadata.encode())
+            state.put(METADATA, pointer.value.encodeToByteArray())
+            state.put(SUPPLY, initialSupply.value.toByteArray())
+            state.put(DEPLOYED, byteArrayOf(1))
+            if (initialSupply.value.signum() > 0) token.mint(owner, initialSupply)
+            pointer
+        }
+
+    fun metadataPointer(): Hash? = state.get(METADATA)?.decodeToString()?.let(::Hash)
+
+    fun metadata(): ByteArray? = metadataPointer()?.let(content::get)
+
+    fun totalSupply(): Amount = Amount(state.get(SUPPLY)?.let(::BigInteger) ?: BigInteger.ZERO)
+
+    fun mint(caller: Address, recipient: Address, amount: Amount) =
+        synchronized(this) {
+            require(caller == owner) { "Only the owner may mint" }
+            check(state.get(DEPLOYED) != null) { "Twisto is not deployed" }
+            require(amount.value.signum() > 0)
+            token.mint(recipient, amount)
+            state.put(SUPPLY, (totalSupply().value + amount.value).toByteArray())
+        }
+
+    override fun balanceOf(owner: Address): Amount = token.balanceOf(owner)
+
+    override fun transfer(from: Address, to: Address, amount: Amount): Boolean =
+        token.transfer(from, to, amount)
+
+    fun contractIr(): ContractIr =
+        contract("Twisto") {
+            allow(AccessOperation.READ, "storage:*", "*")
+            allow(AccessOperation.WRITE, "storage:*", owner.value)
+            allow(AccessOperation.EXECUTE, "*", "*")
+            function("balanceOf", 1) {
+                storageLoad()
+                returnWord()
+            }
+            function("transfer", 2) {
+                storageStore()
+                returnWord()
+            }
+            function("metadata", 3) {
+                storageLoad()
+                returnWord()
+            }
+        }
+
+    private companion object {
+        const val SYMBOL = "TWISTO"
+        val DEPLOYED = "twisto:deployed".encodeToByteArray()
+        val METADATA = "twisto:metadata".encodeToByteArray()
+        val SUPPLY = "twisto:supply".encodeToByteArray()
+    }
+}
--- a/app/src/main/kotlin/rip/crit/twist/wire/FrameCodec.kt
+++ b/app/src/main/kotlin/rip/crit/twist/wire/FrameCodec.kt
@ -0,0 +1,24 @@
+package rip.crit.twist.wire
+
+import java.nio.ByteBuffer
+
+/** Stream for wire payloads. */
+object FrameCodec {
+    const val MAX_FRAME_SIZE = 16 * 1024 * 1024
+
+    fun encode(payload: ByteArray): ByteArray {
+        require(payload.size <= MAX_FRAME_SIZE) { "Frame exceeds maximum size" }
+        return ByteBuffer.allocate(Int.SIZE_BYTES + payload.size)
+            .putInt(payload.size)
+            .put(payload)
+            .array()
+    }
+
+    fun decode(frame: ByteArray): ByteArray {
+        require(frame.size >= Int.SIZE_BYTES) { "Truncated frame" }
+        val buffer = ByteBuffer.wrap(frame)
+        val size = buffer.int
+        require(size in 0..MAX_FRAME_SIZE && size == buffer.remaining()) { "Invalid frame length" }
+        return ByteArray(size).also(buffer::get)
+    }
+}
--- a/app/src/main/kotlin/rip/crit/twist/wire/PacketSpec.kt
+++ b/app/src/main/kotlin/rip/crit/twist/wire/PacketSpec.kt
@ -0,0 +1,73 @@
+package rip.crit.twist.wire
+
+import java.nio.ByteBuffer
+import rip.crit.twist.core.Sha256
+
+/** Twist wire v1 packet, big-endian and checksum-protected. */
+data class WirePacket(val type: PacketType, val payload: ByteArray, val flags: Int = 0) {
+    override fun equals(other: Any?): Boolean =
+        other is WirePacket &&
+            type == other.type &&
+            flags == other.flags &&
+            payload.contentEquals(other.payload)
+
+    override fun hashCode(): Int = 31 * (31 * type.hashCode() + flags) + payload.contentHashCode()
+}
+
+enum class PacketType(val id: Byte) {
+    HELLO(1),
+    PING(2),
+    PONG(3),
+    GOSSIP(4),
+    DHT_LOOKUP(5),
+    DHT_RECORD(6),
+    TRANSACTION(7),
+    BLOCK(8),
+}
+
+object PacketCodec {
+    private const val MAGIC = 0x54575354
+    private const val HEADER_SIZE = 4 + 1 + 1 + 2 + 4 + 32
+    const val MAX_PAYLOAD_SIZE = 16 * 1024 * 1024
+
+    fun encode(packet: WirePacket): ByteArray {
+        require(packet.flags in 0..0xffff && packet.payload.size <= MAX_PAYLOAD_SIZE)
+        val checksum =
+            Sha256.digest(packet.payload)
+                .value
+                .chunked(2)
+                .map { it.toInt(16).toByte() }
+                .toByteArray()
+        return ByteBuffer.allocate(HEADER_SIZE + packet.payload.size)
+            .putInt(MAGIC)
+            .put(1)
+            .put(packet.type.id)
+            .putShort(packet.flags.toShort())
+            .putInt(packet.payload.size)
+            .put(checksum)
+            .put(packet.payload)
+            .array()
+    }
+
+    fun decode(bytes: ByteArray): WirePacket {
+        require(bytes.size >= HEADER_SIZE)
+        val input = ByteBuffer.wrap(bytes)
+        require(input.int == MAGIC && input.get().toInt() == 1)
+        val typeId = input.get()
+        val type =
+            PacketType.entries.firstOrNull { it.id == typeId } ?: error("Unknown packet type")
+        val flags = input.short.toInt() and 0xffff
+        val size = input.int
+        require(size in 0..MAX_PAYLOAD_SIZE && input.remaining() == 32 + size)
+        val checksum = ByteArray(32).also(input::get)
+        val payload = ByteArray(size).also(input::get)
+        require(
+            checksum.contentEquals(
+                Sha256.digest(payload).value.chunked(2).map { it.toInt(16).toByte() }.toByteArray()
+            )
+        ) {
+            "Packet checksum mismatch"
+        }
+        return WirePacket(type, payload, flags)
+    }
+}
--- a/app/src/main/kotlin/rip/crit/twist/wire/Rlp.kt
+++ b/app/src/main/kotlin/rip/crit/twist/wire/Rlp.kt
@ -0,0 +1,145 @@
+package rip.crit.twist.wire
+
+import java.io.ByteArrayOutputStream
+import java.math.BigInteger
+
+/**
+ * Ethereum Recursive Length Prefix (RLP) codec.
+ *
+ * Wire reference: ethereum/devp2p `rlpx.md` — RLPx framing, auth/ack handshake
+ * payloads, and devp2p Hello/Disconnect/Ping/Pong bodies are all RLP-encoded.
+ * Single-byte values < 0x80 are their own encoding; all other strings/lists use
+ * short (<=55 bytes) and long length prefixes.
+ */
+object Rlp {
+  private const val SHORT_MAX = 55
+
+  fun encodeString(bytes: ByteArray): ByteArray =
+      when {
+        bytes.size == 1 && (bytes[0].toInt() and 0xFF) < 0x80 -> bytes.copyOf()
+        bytes.size <= SHORT_MAX ->
+            byteArrayOf((0x80 + bytes.size).toByte()) + bytes
+        else -> {
+          val len = lengthBytes(bytes.size)
+          byteArrayOf((0xB7 + len.size).toByte()) + len + bytes
+        }
+      }
+
+  fun encodeInt(value: BigInteger): ByteArray {
+    require(value >= BigInteger.ZERO) { "RLP integers must be non-negative" }
+    if (value == BigInteger.ZERO) return byteArrayOf(0x80.toByte())
+    var raw = value.toByteArray().dropWhile { it == 0.toByte() }.toByteArray()
+    return encodeString(raw)
+  }
+
+  fun encodeInt(value: Long): ByteArray = encodeInt(BigInteger.valueOf(value))
+
+  fun encodeList(items: List<ByteArray>): ByteArray {
+    val payload = items.fold(ByteArray(0)) { acc, item -> acc + item }
+    return when {
+      payload.size <= SHORT_MAX ->
+          byteArrayOf((0xC0 + payload.size).toByte()) + payload
+      else -> {
+        val len = lengthBytes(payload.size)
+        byteArrayOf((0xF7 + len.size).toByte()) + len + payload
+      }
+    }
+  }
+
+  fun encodeElements(vararg items: ByteArray): ByteArray = encodeList(items.toList())
+
+  /** Decodes one RLP item starting at [offset]; returns (item, nextOffset). */
+  fun decodeOne(bytes: ByteArray, offset: Int = 0): Pair<RlpItem, Int> {
+    require(offset < bytes.size) { "RLP truncated" }
+    val prefix = bytes[offset].toInt() and 0xFF
+    return when {
+      prefix < 0x80 -> Pair(RlpItem.String(bytes.copyOfRange(offset, offset + 1)), offset + 1)
+      prefix <= 0xB7 -> {
+        val len = prefix - 0x80
+        require(offset + 1 + len <= bytes.size) { "RLP string truncated" }
+        Pair(RlpItem.String(bytes.copyOfRange(offset + 1, offset + 1 + len)), offset + 1 + len)
+      }
+      prefix <= 0xBF -> {
+        val lenOfLen = prefix - 0xB7
+        val len = readLength(bytes, offset + 1, lenOfLen)
+        require(offset + 1 + lenOfLen + len <= bytes.size) { "RLP long string truncated" }
+        Pair(
+            RlpItem.String(bytes.copyOfRange(offset + 1 + lenOfLen, offset + 1 + lenOfLen + len)),
+            offset + 1 + lenOfLen + len)
+      }
+      prefix <= 0xF7 -> {
+        val len = prefix - 0xC0
+        require(offset + 1 + len <= bytes.size) { "RLP list truncated" }
+        Pair(decodeList(bytes.copyOfRange(offset + 1, offset + 1 + len)), offset + 1 + len)
+      }
+      else -> {
+        val lenOfLen = prefix - 0xF7
+        val len = readLength(bytes, offset + 1, lenOfLen)
+        require(offset + 1 + lenOfLen + len <= bytes.size) { "RLP long list truncated" }
+        Pair(
+            decodeList(bytes.copyOfRange(offset + 1 + lenOfLen, offset + 1 + lenOfLen + len)),
+            offset + 1 + lenOfLen + len)
+      }
+    }
+  }
+
+  fun decode(bytes: ByteArray): RlpItem {
+    val (item, next) = decodeOne(bytes, 0)
+    require(next == bytes.size) { "Trailing RLP bytes" }
+    return item
+  }
+
+  private fun decodeList(payload: ByteArray): RlpItem.List {
+    val items = mutableListOf<RlpItem>()
+    var offset = 0
+    while (offset < payload.size) {
+      val (item, next) = decodeOne(payload, offset)
+      items += item
+      offset = next
+    }
+    require(offset == payload.size) { "RLP list overrun" }
+    return RlpItem.List(items)
+  }
+
+  private fun readLength(bytes: ByteArray, offset: Int, lenOfLen: Int): Int {
+    require(lenOfLen in 1..4 && offset + lenOfLen <= bytes.size) { "Bad RLP length prefix" }
+    require(bytes[offset] != 0.toByte()) { "RLP length has leading zero" }
+    var len = 0
+    for (i in 0 until lenOfLen) len = (len shl 8) or (bytes[offset + i].toInt() and 0xFF)
+    require(len > SHORT_MAX) { "RLP long form used for short payload" }
+    return len
+  }
+
+  private fun lengthBytes(size: Int): ByteArray {
+    val out = ByteArrayOutputStream()
+    var v = size
+    val tmp = mutableListOf<Byte>()
+    while (v > 0) {
+      tmp += (v and 0xFF).toByte()
+      v = v ushr 8
+    }
+    tmp.reversed().forEach { out.write(it.toInt()) }
+    return out.toByteArray()
+  }
+}
+
+sealed interface RlpItem {
+  data class String(val bytes: ByteArray) : RlpItem {
+    fun asLong(): Long {
+      require(bytes.isNotEmpty()) { "Empty RLP int" }
+      require(!(bytes.size > 1 && bytes[0] == 0.toByte())) { "Non-canonical RLP int" }
+      var v = 0L
+      for (b in bytes) v = (v shl 8) or (b.toLong() and 0xFF)
+      return v
+    }
+
+    fun asText(): kotlin.String = bytes.decodeToString()
+
+    override fun equals(other: Any?): Boolean =
+        other is String && bytes.contentEquals(other.bytes)
+
+    override fun hashCode(): Int = bytes.contentHashCode()
+  }
+
+  data class List(val items: kotlin.collections.List<RlpItem>) : RlpItem
+}
--- a/app/src/main/kotlin/rip/crit/twist/wire/WireCodec.kt
+++ b/app/src/main/kotlin/rip/crit/twist/wire/WireCodec.kt
@ -0,0 +1,92 @@
+package rip.crit.twist.wire
+
+import java.io.ByteArrayInputStream
+import java.io.ByteArrayOutputStream
+import java.io.DataInputStream
+import java.io.DataOutputStream
+import java.math.BigInteger
+import rip.crit.twist.core.Address
+import rip.crit.twist.core.Amount
+import rip.crit.twist.core.Hash
+import rip.crit.twist.core.Transaction
+import rip.crit.twist.p2p.NetworkMessage
+
+/** Length-prefixed envelope shared by devp2p-twist subprotocol payloads. */
+object WireEnvelope {
+  fun encode(message: NetworkMessage): ByteArray = WireCodec.encode(message)
+
+  fun decode(bytes: ByteArray): NetworkMessage = WireCodec.decodeNetworkMessage(bytes)
+}
+
+object WireCodec {
+    private const val VERSION: Byte = 1
+    private const val MAX_FIELD_SIZE = 16 * 1024 * 1024
+
+    fun encode(transaction: Transaction): ByteArray = bytes {
+        writeByte(VERSION.toInt())
+        writeString(transaction.id.value)
+        writeString(transaction.sender.value)
+        writeBoolean(transaction.recipient != null)
+        transaction.recipient?.let { writeString(it.value) }
+        writeLong(transaction.nonce)
+        writeBytes(transaction.value.value.toByteArray())
+        writeBytes(transaction.payload)
+    }
+
+    fun decodeTransaction(bytes: ByteArray): Transaction =
+        DataInputStream(ByteArrayInputStream(bytes)).use {
+            requireVersion(it)
+            val id = Hash(it.readString())
+            val sender = Address(it.readString())
+            val recipient = if (it.readBoolean()) Address(it.readString()) else null
+            val nonce = it.readLong()
+            require(nonce >= 0) { "Transaction nonce cannot be negative" }
+            val value = Amount(BigInteger(it.readBytes()))
+            val payload = it.readBytes()
+            require(it.available() == 0) { "Trailing transaction bytes" }
+            Transaction(id, sender, recipient, nonce, value, payload)
+        }
+
+    fun encode(message: NetworkMessage): ByteArray = bytes {
+        writeByte(VERSION.toInt())
+        writeString(message.id.value)
+        writeString(message.topic)
+        writeBytes(message.payload)
+    }
+
+    fun decodeNetworkMessage(bytes: ByteArray): NetworkMessage =
+        DataInputStream(ByteArrayInputStream(bytes)).use {
+            requireVersion(it)
+            val id = Hash(it.readString())
+            val topic = it.readString()
+            val message = NetworkMessage(topic, it.readBytes(), id)
+            require(it.available() == 0) { "Trailing message bytes" }
+            message
+        }
+
+    private fun bytes(write: DataOutputStream.() -> Unit): ByteArray =
+        ByteArrayOutputStream().use { output ->
+            DataOutputStream(output).use { it.write() }
+            output.toByteArray()
+        }
+
+    private fun requireVersion(input: DataInputStream) {
+        require(input.readByte() == VERSION) { "Unsupported wire version" }
+    }
+
+    private fun DataOutputStream.writeString(value: String) = writeBytes(value.encodeToByteArray())
+
+    private fun DataOutputStream.writeBytes(value: ByteArray) {
+        require(value.size <= MAX_FIELD_SIZE)
+        writeInt(value.size)
+        write(value)
+    }
+
+    private fun DataInputStream.readString(): String = readBytes().decodeToString()
+
+    private fun DataInputStream.readBytes(): ByteArray {
+        val size = readInt()
+        require(size in 0..MAX_FIELD_SIZE) { "Invalid wire field length" }
+        return ByteArray(size).also(::readFully)
+    }
+}
--- a/app/src/test/kotlin/rip/crit/twist/AppTest.kt
+++ b/app/src/test/kotlin/rip/crit/twist/AppTest.kt
@ -0,0 +1,465 @@
+package rip.crit.twist
+
+import rip.crit.twist.access.AccessList
+import rip.crit.twist.bips.FileStorageContract
+import rip.crit.twist.bytecode.TwistBytecode
+import rip.crit.twist.compiler.TwistCompiler
+import rip.crit.twist.compiler.LispIrCompiler
+import rip.crit.twist.compiler.contract
+import rip.crit.twist.core.Address
+import rip.crit.twist.core.Amount
+import rip.crit.twist.core.Hash
+import rip.crit.twist.core.Sha256
+import rip.crit.twist.core.TransactionHasher
+import rip.crit.twist.core.TwistSpecific
+import rip.crit.twist.gas.BasicGasMeter
+import rip.crit.twist.gas.GasLimit
+import rip.crit.twist.gas.OutOfGasException
+import rip.crit.twist.merkle.Sha256MerkleTree
+import rip.crit.twist.merkle.verifies
+import rip.crit.twist.p2p.NetworkMessage
+import rip.crit.twist.p2p.InMemoryDht
+import rip.crit.twist.p2p.PeerId
+import rip.crit.twist.proof.ProofOfAuthority
+import rip.crit.twist.proof.ProofOfWork
+import rip.crit.twist.state.Account
+import rip.crit.twist.state.FileWorldState
+import rip.crit.twist.state.InMemoryWorldState
+import rip.crit.twist.store.InMemoryKeyValueStore
+import rip.crit.twist.wire.FrameCodec
+import rip.crit.twist.wire.WireCodec
+import rip.crit.twist.wire.PacketCodec
+import rip.crit.twist.wire.PacketType
+import rip.crit.twist.wire.WirePacket
+import rip.crit.twist.transport.X25519Session
+import rip.crit.twist.transport.Aes
+import rip.crit.twist.transport.AesGcm
+import rip.crit.twist.transport.X25519
+import rip.crit.twist.transport.TwistOverlayAdapter
+import rip.crit.twist.ecdsa.Secp256k1Ecdsa
+import rip.crit.twist.rsa.RsaKeyPair
+import rip.crit.twist.rsa.RsaOaep
+import rip.crit.twist.store.FileKeyValueStore
+import rip.crit.twist.tvm.Calldata
+import rip.crit.twist.tvm.TransientStorage
+import rip.crit.twist.tvm.Word256
+import rip.crit.twist.tvm.BytecodeVirtualMachine
+import rip.crit.twist.bytecode.Instruction
+import rip.crit.twist.bytecode.OpCode
+import rip.crit.twist.p2p.PeerNetwork
+import rip.crit.twist.transport.TcpPeerNetwork
+import rip.crit.twist.p2p.DevP2pAdapter
+import rip.crit.twist.p2p.DevP2pHello
+import rip.crit.twist.p2p.LibP2pAdapter
+import rip.crit.twist.p2p.ProtocolCapability
+import rip.crit.twist.router.NetworkResultDistributor
+import rip.crit.twist.router.OffchainComputation
+import rip.crit.twist.router.OffchainJob
+import rip.crit.twist.router.OffchainRouter
+import rip.crit.twist.router.OffchainWorker
+import rip.crit.twist.router.ProofPolicy
+import java.math.BigInteger
+import java.nio.file.Files
+import java.time.Duration
+import java.time.Instant
+import java.util.concurrent.CountDownLatch
+import java.util.concurrent.TimeUnit
+import kotlin.test.Test
+import kotlin.test.assertFalse
+import kotlin.test.assertFailsWith
+import kotlin.test.assertEquals
+import kotlin.test.assertNotEquals
+import kotlin.test.assertNotNull
+import kotlin.test.assertTrue
+import rip.crit.twist.did.DidKey
+import rip.crit.twist.did.DidMethodRegistry
+import rip.crit.twist.did.DidTwist
+import rip.crit.twist.did.KeyCodec
+import rip.crit.twist.miner.CpuMiner
+import rip.crit.twist.reflect.NetworkReflector
+import rip.crit.twist.reflect.PeerIndex
+import rip.crit.twist.reflect.PeerObservation
+import rip.crit.twist.reflect.PeerProbe
+import rip.crit.twist.twisto.TwistoMetadata
+import rip.crit.twist.twisto.TwistoToken
+import rip.crit.twist.smartdoc.SmartDocGenerator
+import java.nio.file.Path
+
+class AppTest {
+    @Test
+    fun accessListsIdentifyWriteConflicts() {
+        val alice = Address("alice")
+        val bob = Address("bob")
+
+        assertTrue(AccessList(writes = setOf(alice)).conflictsWith(AccessList(reads = setOf(alice))))
+        assertFalse(AccessList(writes = setOf(alice)).conflictsWith(AccessList(reads = setOf(bob))))
+    }
+
+    @Test
+    fun sha256AndTransactionIdsAreDeterministic() {
+        assertEquals(
+            "e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855",
+            Sha256.digest(byteArrayOf()).value
+        )
+        val transaction =
+            TransactionHasher.create(Address("alice"), Address("bob"), 1, Amount(BigInteger.TEN), byteArrayOf(1))
+        assertEquals(
+            transaction.id,
+            TransactionHasher.hash(
+                transaction.sender,
+                transaction.recipient,
+                transaction.nonce,
+                transaction.value,
+                transaction.payload
+            )
+        )
+    }
+
+    @Test
+    fun merkleProofVerifiesAndStateIsDefensive() {
+        val leaves = listOf("one", "two", "three").map(Sha256::digestUtf8)
+        val tree = Sha256MerkleTree(leaves)
+        assertTrue(tree.proofFor(leaves[1])!!.verifies(tree.root))
+
+        val state = InMemoryWorldState()
+        val account = Account(balance = Amount(BigInteger.ONE), code = byteArrayOf(7))
+        state.putAccount(Address("alice"), account)
+        account.code[0] = 9
+        assertEquals(7, state.account(Address("alice"))!!.code[0])
+        assertNotEquals(state.rootHash(), Sha256.digestUtf8("different"))
+    }
+
+    @Test
+    fun storesCopyValuesAndGasCannotOverflowLimit() {
+        val store = InMemoryKeyValueStore()
+        val value = byteArrayOf(1)
+        store.put(byteArrayOf(1), value)
+        value[0] = 2
+        assertEquals(1, store.get(byteArrayOf(1))!![0])
+
+        val meter = BasicGasMeter(GasLimit(3))
+        meter.consume(3)
+        assertEquals(3, meter.used.value)
+        assertFailsWith<OutOfGasException> { meter.consume(1) }
+        assertNotNull(store.get(byteArrayOf(1)))
+    }
+
+    @Test
+    fun wireCodecRoundTripsTransactionsAndNetworkFrames() {
+        val transaction =
+            TransactionHasher.create(Address("alice"), Address("bob"), 4, Amount(BigInteger.TEN), byteArrayOf(1, 2))
+        assertEquals(transaction, WireCodec.decodeTransaction(WireCodec.encode(transaction)))
+        assertEquals(byteArrayOf(1, 2).toList(), FrameCodec.decode(FrameCodec.encode(byteArrayOf(1, 2))).toList())
+        val message = NetworkMessage("transactions", byteArrayOf(9), Hash("message-id"))
+        assertEquals(message, WireCodec.decodeNetworkMessage(WireCodec.encode(message)))
+    }
+
+    @Test
+    fun tcpPeerNetworksHandshakeAndBroadcast() {
+        val first = TcpPeerNetwork(PeerId("first"))
+        val second = TcpPeerNetwork(PeerId("second"))
+        val received = CountDownLatch(1)
+        second.subscribe { received.countDown() }
+        first.start()
+        second.start()
+        try {
+            second.connect("127.0.0.1", first.port)
+            repeat(50) {
+                if (first.peers().contains(PeerId("second"))) return@repeat
+                Thread.sleep(10)
+            }
+            first.broadcast(NetworkMessage("test", byteArrayOf(1), Hash("tcp-message")))
+            assertTrue(received.await(2, TimeUnit.SECONDS))
+            assertTrue(first.peers().contains(PeerId("second")))
+        } finally {
+            first.stop()
+            second.stop()
+        }
+    }
+
+    @Test
+    fun compatibilityAdaptersNegotiateAndPreserveMessages() {
+        val dev = DevP2pAdapter(setOf(ProtocolCapability("twist", 1), ProtocolCapability("twist", 2)))
+        val hello = DevP2pHello("peer", 9000, PeerId("remote"), setOf(ProtocolCapability("twist", 2)))
+        assertEquals(setOf(ProtocolCapability("twist", 2)), dev.negotiate(hello))
+        val message = NetworkMessage("blocks", byteArrayOf(2), Hash("adapter-message"))
+        assertEquals(message, dev.decode(dev.encode(message)))
+        val lib = LibP2pAdapter(setOf("/twist/1.0.0", "/twist/2.0.0"))
+        assertEquals("/twist/2.0.0", lib.select(setOf("/twist/2.0.0")))
+        assertEquals(message, lib.decode(lib.encode(message)))
+    }
+
+    @Test
+    fun smartDocProducesBrowsableStaticReference() {
+        val output = Files.createTempDirectory("twist-smartdoc")
+        val entries = SmartDocGenerator.generate(Path.of("app/src/main/kotlin"), output)
+        assertTrue(entries.any { it.name == "BytecodeVirtualMachine" })
+        assertTrue(Files.readString(output.resolve("index.html")).contains("Twist SmartDoc API"))
+    }
+
+    @Test
+    fun phaseThreeCompilerAndStoragePrimitivesWork() {
+        assertEquals(Word256.ZERO, Word256.of(BigInteger.ONE.shiftLeft(256)))
+        assertEquals(BigInteger.ONE, Calldata.wrap(ByteArray(31) + byteArrayOf(1)).wordAt(0).toBigInteger())
+        val transient = TransientStorage(); transient.put(
+            Address("contract"),
+            Word256.ZERO,
+            Word256.fromLong(5)
+        ); assertEquals(BigInteger.valueOf(5), transient.get(Address("contract"), Word256.ZERO).toBigInteger())
+        assertEquals(2, TwistBytecode.decode(TwistCompiler().compile("PUSH32 1\nSTOP")).size)
+        val folder = Files.createTempDirectory("twist-bips-test")
+        val storage = FileStorageContract(folder)
+        val hash = storage.put(byteArrayOf(4)); assertTrue(storage.prove(hash, Hash("challenge"))!!.verify())
+    }
+
+    @Test
+    fun peerAndConsensusAdaptersHaveSafeLocalFoundations() {
+        val dht = InMemoryDht()
+        val key = dht.announce(PeerId("peer-a"), setOf("memory://peer-a")); assertEquals(
+            PeerId("peer-a"),
+            dht.get(key)!!.peer
+        )
+        val adapter = TwistOverlayAdapter(TwistSpecific.Enabled, ByteArray(32) { 1 })
+        val message = NetworkMessage("blocks", byteArrayOf(3), Hash("block-message")); assertEquals(
+            message,
+            adapter.decode(adapter.encode(message))
+        )
+        val subject = Hash("pow-subject"); assertTrue(ProofOfWork.mine(subject, 1, 1_000)!!.verify())
+        assertTrue(ProofOfAuthority.sign(subject, "validator-a", setOf("validator-a")).verify())
+    }
+
+    @Test
+    fun authenticatedWireAndFileStoreRoundTrip() {
+        val packet = WirePacket(PacketType.PING, byteArrayOf(1, 2), flags = 5)
+        assertEquals(packet, PacketCodec.decode(PacketCodec.encode(packet)))
+        val local = X25519Session.generateKeyPair()
+        val remote = X25519Session.generateKeyPair()
+        val sender = X25519Session.establish(local.privateKey, remote.publicKey)
+        val receiver = X25519Session.establish(remote.privateKey, local.publicKey)
+        assertEquals(
+            "secret",
+            receiver.decrypt(sender.encrypt("secret".encodeToByteArray(), ByteArray(12)), ByteArray(12))
+                .decodeToString()
+        )
+        val root = Files.createTempDirectory("twist-store-test")
+        val store = FileKeyValueStore(root); store.put(byteArrayOf(7), byteArrayOf(8)); assertEquals(
+            8,
+            store.get(byteArrayOf(7))!![0]
+        )
+    }
+
+    @Test
+    fun cryptoMatchesPublishedVectors() {
+        val aes = Aes(hex("000102030405060708090a0b0c0d0e0f"))
+        assertEquals(
+            "69c4e0d86a7b0430d8cdb78070b4c55a",
+            aes.encryptBlock(hex("00112233445566778899aabbccddeeff")).hex()
+        )
+        val gcm = AesGcm(ByteArray(16))
+        val encrypted = gcm.encrypt(ByteArray(12), ByteArray(16))
+        assertEquals("0388dace60b6a392f328c2b971b2fe78", encrypted.ciphertext.hex())
+        assertEquals("ab6e47d42cec13bdf53a67b21257bddf", encrypted.tag.hex())
+        val scalar = hex("a546e36bf0527c9d3b16154b82465edd62144c0ac1fc5a18506a2244ba449ac4")
+        val u = hex("e6db6867583030db3594c1a424b15f7c726624ec26b3353b10a903a6d0ab1c4c")
+        assertEquals(
+            "c3da55379de9c6908e94ea4df28d084f32eccf03491c71f754b4075577a28552",
+            X25519.scalarMult(scalar, u).hex()
+        )
+        val ecdsa = Secp256k1Ecdsa()
+        val privateKey = ByteArray(32).also { it[31] = 1 }
+        val signature = ecdsa.sign("message".encodeToByteArray(), privateKey)
+        assertTrue(ecdsa.verify("message".encodeToByteArray(), signature, ecdsa.publicKey(privateKey)))
+        assertFalse(ecdsa.verify("tampered".encodeToByteArray(), signature, ecdsa.publicKey(privateKey)))
+        val rsa = RsaKeyPair.fromPrimes(
+            BigInteger.TWO.pow(521) - BigInteger.ONE,
+            BigInteger.TWO.pow(607) - BigInteger.ONE
+        )
+        val ciphertext =
+            RsaOaep.encrypt("rsa".encodeToByteArray(), rsa.publicKey, ByteArray(32) { it.toByte() })
+        assertEquals("rsa", RsaOaep.decrypt(ciphertext, rsa.privateKey).decodeToString())
+        val damaged = ciphertext.copyOf().also { it[it.lastIndex] = (it.last().toInt() xor 1).toByte() }
+        assertFailsWith<IllegalArgumentException> { RsaOaep.decrypt(damaged, rsa.privateKey) }
+    }
+
+    @Test
+    fun contractIrExecutesAgainstFileBackedState() {
+        val ir = contract("Storage") {
+            function("setAndGet", 1) {
+                push(7)
+                push(42)
+                storageStore()
+                push(7)
+                storageLoad()
+                returnWord()
+            }
+        }
+        val state = FileWorldState(Files.createTempDirectory("twist-world-state"))
+        val transaction = TransactionHasher.create(
+            Address("caller"),
+            Address("storage-contract"),
+            0,
+            Amount(BigInteger.ZERO),
+            ir.bytecode(),
+        )
+        val result = BytecodeVirtualMachine().execute(transaction, state)
+        assertTrue(result.succeeded)
+        assertEquals(BigInteger.valueOf(42), Word256.fromBytes(result.returnData).toBigInteger())
+        assertNotEquals(Sha256.digest(byteArrayOf()), state.rootHash())
+    }
+
+    @Test
+    fun extendedVmMemoryAndEnvironmentInstructionsExecute() {
+        val code =
+            TwistBytecode.encode(
+                listOf(
+                    Instruction(OpCode.PUSH32, Word256.ZERO.toBytes()),
+                    Instruction(OpCode.PUSH32, Word256.fromLong(99).toBytes()),
+                    Instruction(OpCode.MSTORE),
+                    Instruction(OpCode.PUSH32, Word256.ZERO.toBytes()),
+                    Instruction(OpCode.MLOAD),
+                    Instruction(OpCode.RETURN),
+                )
+            )
+        val result = BytecodeVirtualMachine().execute(code, byteArrayOf(), Address("memory"))
+        assertTrue(result.succeeded)
+        assertEquals(BigInteger.valueOf(99), Word256.fromBytes(result.returnData).toBigInteger())
+    }
+
+    @Test
+    fun offchainRouterSignsProvesPersistsAndDistributesResults() {
+        val messages = mutableListOf<NetworkMessage>()
+        val network =
+            object : PeerNetwork {
+                override fun start() = Unit
+                override fun stop() = Unit
+                override fun peers() = emptySet<PeerId>()
+                override fun broadcast(message: NetworkMessage) {
+                    messages += message
+                }
+            }
+        val store = InMemoryKeyValueStore()
+        val router = NetworkResultDistributor(network, store).let(::OffchainRouter)
+        val signer = Secp256k1Ecdsa()
+        val privateKey = ByteArray(32).also { it[31] = 7 }
+        val worker =
+            OffchainWorker(
+                Address("worker-7"),
+                privateKey,
+                signer.publicKey(privateKey),
+                OffchainComputation { it.reversedArray() },
+            )
+        router.register(worker)
+        val job =
+            OffchainJob(
+                Hash("job-1"),
+                Address("requester"),
+                "compute".encodeToByteArray(),
+                proofPolicy = ProofPolicy.Work(1, 10_000),
+            )
+        val result = router.route(job)
+        assertTrue(router.verify(job, result))
+        assertEquals("etupmoc", result.output.decodeToString())
+        assertEquals(1, messages.size)
+        assertNotNull(store.get(job.id.value.encodeToByteArray()))
+    }
+
+    @Test
+    fun lispIrEnforcesReadWriteAndExecuteCapabilities() {
+        val source =
+            """
+            (contract Vault
+              (access
+                (read storage:* alice)
+                (write storage:* alice)
+                (execute function:set alice))
+              (function set 1
+                (push32 7)
+                (push32 42)
+                (sstore)
+                (return)))
+            """.trimIndent()
+        assertTrue(LispIrCompiler().compile(source, "alice").isNotEmpty())
+        assertFailsWith<IllegalArgumentException> { LispIrCompiler().compile(source, "mallory") }
+    }
+
+    @Test
+    fun didMethodsResolveDocuments() {
+        val publicKey = ByteArray(32) { it.toByte() }
+        val keyDid = DidKey.create(publicKey, KeyCodec.X25519)
+        assertEquals(keyDid, DidKey.resolve(keyDid).id)
+        val dht = InMemoryDht()
+        val documents = InMemoryKeyValueStore()
+        val twist = DidTwist(TwistSpecific.Enabled, dht, documents)
+        val twistDid =
+            twist.create(
+                PeerId("node-a"),
+                publicKey,
+                setOf("twist://node-a"),
+                Duration.ofMinutes(5),
+            )
+        assertEquals("twist://node-a", twist.resolve(twistDid)!!.services.single().endpoint)
+        assertEquals(
+            twistDid,
+            DidMethodRegistry.create(TwistSpecific.Enabled, twist).resolve(twistDid)!!.id,
+        )
+        assertFailsWith<IllegalArgumentException> { DidMethodRegistry.create(twist = twist) }
+    }
+
+    @Test
+    fun minerAndReflectorAreBoundedAndPersistent() {
+        assertNotNull(CpuMiner(2).mine(Hash("cpu-miner"), 1, 10_000).proof)
+        val store = InMemoryKeyValueStore()
+        val index = PeerIndex(store)
+        val reflector =
+            NetworkReflector(
+                PeerProbe { peer ->
+                    PeerObservation(
+                        peer,
+                        setOf("memory://${peer.value}"),
+                        if (peer.value == "a") setOf(PeerId("b")) else emptySet(),
+                        Instant.EPOCH,
+                    )
+                },
+                index,
+            )
+        val report = reflector.crawl(listOf(PeerId("a")), 2)
+        assertEquals(2, report.observations.size)
+        assertNotNull(index.get(PeerId("b")))
+    }
+
+    @Test
+    fun authenticatedEncryptionRejectsModification() {
+        val cipher = AesGcm(ByteArray(32) { it.toByte() })
+        val encrypted = cipher.encrypt(ByteArray(12), "authenticated".encodeToByteArray())
+        val altered = encrypted.ciphertext.copyOf().also { it[0] = (it[0].toInt() xor 1).toByte() }
+        assertFailsWith<IllegalArgumentException> {
+            cipher.decrypt(ByteArray(12), altered, encrypted.tag)
+        }
+        val alice = X25519Session.generateKeyPair(kotlin.random.Random(1))
+        val bob = X25519Session.generateKeyPair(kotlin.random.Random(2))
+        assertEquals(
+            X25519.sharedSecret(alice.privateKey, bob.publicKey).toList(),
+            X25519.sharedSecret(bob.privateKey, alice.publicKey).toList(),
+        )
+    }
+
+    @Test
+    fun twistoPersistsContentAddressedMetadataAndBalances() {
+        val state = InMemoryKeyValueStore()
+        val storage = FileStorageContract(Files.createTempDirectory("twisto-metadata"))
+        val owner = Address("owner")
+        val token = TwistoToken(owner, state, storage)
+        val pointer =
+            token.deploy(TwistoMetadata(description = "Test token"), Amount(BigInteger.TEN))
+        assertEquals(pointer, token.metadataPointer())
+        assertEquals(TwistoMetadata(description = "Test token").encode().toList(), token.metadata()!!.toList())
+        assertTrue(token.metadata()!!.decodeToString().contains("\"schema\":\"twisto-metadata/1\""))
+        assertEquals(BigInteger.TEN, token.balanceOf(owner).value)
+        assertFailsWith<IllegalArgumentException> {
+            token.mint(Address("attacker"), Address("attacker"), Amount(BigInteger.ONE))
+        }
+    }
+
+    private fun hex(value: String): ByteArray = value.chunked(2).map { it.toInt(16).toByte() }.toByteArray()
+    private fun ByteArray.hex(): String = joinToString("") { "%02x".format(it) }
+}
--- a/apps/compiler/build.gradle.kts
+++ b/apps/compiler/build.gradle.kts
@ -0,0 +1 @@
+// Configured by the root build.
--- a/apps/compiler/src/main/kotlin/rip/crit/twist/tool/compiler/Main.kt
+++ b/apps/compiler/src/main/kotlin/rip/crit/twist/tool/compiler/Main.kt
@ -0,0 +1,21 @@
+package rip.crit.twist.tool.compiler
+
+import java.nio.file.Files
+import java.nio.file.Path
+import rip.crit.twist.compiler.TwistCompiler
+import rip.crit.twist.compiler.LispIrCompiler
+
+fun main(args: Array<String>) {
+    require(args.size in 2..3) {
+        "Usage is twistc <source.twistasm|source.twistl> <output.tbc> [principal]"
+    }
+    val source = Path.of(args[0])
+    val text = Files.readString(source)
+    val bytecode =
+        if (source.fileName.toString().endsWith(".twistl")) {
+            LispIrCompiler().compile(text, args.getOrNull(2) ?: "anonymous")
+        } else {
+            TwistCompiler().compile(text)
+        }
+    Files.write(Path.of(args[1]), bytecode)
+}
--- a/apps/docs/build.gradle.kts
+++ b/apps/docs/build.gradle.kts
@ -0,0 +1 @@
+description = "SmartDoc static documentation generator"
--- a/apps/docs/src/main/kotlin/rip/crit/twist/tool/docs/Main.kt
+++ b/apps/docs/src/main/kotlin/rip/crit/twist/tool/docs/Main.kt
@ -0,0 +1,11 @@
+package rip.crit.twist.tool.docs
+
+import java.nio.file.Path
+import rip.crit.twist.smartdoc.SmartDocGenerator
+
+fun main(args: Array<String>) {
+    val source = Path.of(args.getOrNull(0) ?: "app/src/main/kotlin")
+    val output = Path.of(args.getOrNull(1) ?: "build/docs/api")
+    val entries = SmartDocGenerator.generate(source, output)
+    println("Generated ${entries.size} SmartDoc entries at $output/index.html")
+}
--- a/apps/miner/build.gradle.kts
+++ b/apps/miner/build.gradle.kts
@ -0,0 +1 @@
+description = "Twist CPU miner command-line tool"
--- a/apps/miner/src/main/kotlin/rip/crit/twist/tool/miner/Main.kt
+++ b/apps/miner/src/main/kotlin/rip/crit/twist/tool/miner/Main.kt
@ -0,0 +1,31 @@
+package rip.crit.twist.tool.miner
+
+import java.math.BigInteger
+import java.nio.file.Path
+import rip.crit.twist.core.Address
+import rip.crit.twist.core.Amount
+import rip.crit.twist.core.Hash
+import rip.crit.twist.miner.CpuMiner
+import rip.crit.twist.stake.PersistentStaking
+import rip.crit.twist.store.FileKeyValueStore
+import rip.crit.twist.proof.ProofOfWork
+import rip.crit.twist.miner.MiningResult
+
+fun main(args: Array<String>) {
+    require(args.isNotEmpty()) {
+        "Usage is twist-miner mine <subject> <difficulty> [attempts] [threads], or stake <folder> <delegator> <validator> <amount>"
+    }
+    if (args[0] == "stake") {
+        require(args.size == 5)
+        val staking = PersistentStaking(FileKeyValueStore(Path.of(args[1])))
+        val validator = Address(args[3])
+        staking.stake(Address(args[2]), validator, Amount(BigInteger(args[4])))
+        println("staked validator=${validator.value} power=${staking.votingPower(validator).value}")
+        return
+    }
+    require(args[0] == "mine" && args.size in 3..5)
+    val result =
+        CpuMiner(args.getOrNull(4)?.toInt() ?: Runtime.getRuntime().availableProcessors())
+            .mine(Hash(args[1]), args[2].toInt(), args.getOrNull(3)?.toLong() ?: 1_000_000) as MiningResult
+    println("subject=${result.subject.value} difficulty=${result.difficulty} proof=${result.proof?.nonce} attempts=${result.attempts} elapsedNanos=${result.elapsedNanos}")
+}
--- a/apps/reflect/build.gradle.kts
+++ b/apps/reflect/build.gradle.kts
@ -0,0 +1 @@
+description = "Twist network reflection command-line tool"
--- a/apps/reflect/src/main/kotlin/rip/crit/twist/tool/reflect/Main.kt
+++ b/apps/reflect/src/main/kotlin/rip/crit/twist/tool/reflect/Main.kt
@ -0,0 +1,23 @@
+package rip.crit.twist.tool.reflect
+
+import java.nio.file.Path
+import java.time.Instant
+import rip.crit.twist.p2p.PeerId
+import rip.crit.twist.reflect.NetworkReflector
+import rip.crit.twist.reflect.PeerIndex
+import rip.crit.twist.reflect.PeerObservation
+import rip.crit.twist.reflect.PeerProbe
+import rip.crit.twist.store.FileKeyValueStore
+
+fun main(args: Array<String>) {
+    require(args.size >= 2) { "Usage is twist-reflect <index-folder> <seed> [seed...]" }
+    val index = PeerIndex(FileKeyValueStore(Path.of(args[0])))
+    val probe =
+        PeerProbe { peer ->
+            PeerObservation(peer, emptySet(), emptySet(), Instant.EPOCH)
+        }
+    val report = NetworkReflector(probe, index).crawl(args.drop(1).map(::PeerId))
+    println(
+        "observed=${report.observations.size} failures=${report.failures.size} truncated=${report.truncated}"
+    )
+}
--- a/apps/twisto/build.gradle.kts
+++ b/apps/twisto/build.gradle.kts
@ -0,0 +1 @@
+description = "Twisto deployment example"
--- a/apps/twisto/src/main/kotlin/rip/crit/twist/tool/twisto/Main.kt
+++ b/apps/twisto/src/main/kotlin/rip/crit/twist/tool/twisto/Main.kt
@ -0,0 +1,31 @@
+package rip.crit.twist.tool.twisto
+
+import java.math.BigInteger
+import java.nio.file.Path
+import rip.crit.twist.bips.FileStorageContract
+import rip.crit.twist.core.Address
+import rip.crit.twist.core.Amount
+import rip.crit.twist.store.FileKeyValueStore
+import rip.crit.twist.twisto.TwistoMetadata
+import rip.crit.twist.twisto.TwistoToken
+
+fun main(args: Array<String>) {
+    require(args.size in 1..3) {
+        "Usage is twisto <data-folder> [owner] [initial-supply]"
+    }
+    val root = Path.of(args[0])
+    val owner = Address(args.getOrNull(1) ?: "twisto-owner")
+    val token =
+        TwistoToken(
+            owner,
+            FileKeyValueStore(root.resolve("state")),
+            FileStorageContract(root.resolve("metadata")),
+        )
+    val pointer =
+        token.metadataPointer()
+            ?: token.deploy(
+                TwistoMetadata(description = "Named token on the Twist network"),
+                Amount(BigInteger(args.getOrNull(2) ?: "1000000")),
+            )
+    println("deployed symbol=${token.symbol} metadata=${pointer.value} owner=${owner.value}")
+}
--- a/build.gradle.kts
+++ b/build.gradle.kts
@ -0,0 +1,186 @@
+import org.jetbrains.kotlin.gradle.dsl.KotlinJvmProjectExtension
+import org.jetbrains.kotlin.gradle.tasks.KotlinCompile
+import org.gradle.api.plugins.JavaApplication
+import org.gradle.api.publish.PublishingExtension
+import org.gradle.api.publish.maven.MavenPublication
+import org.gradle.authentication.http.BasicAuthentication
+import org.gradle.api.credentials.PasswordCredentials
+
+plugins {
+    kotlin("jvm") version "2.4.0" apply false
+    id("com.ncorti.ktfmt.gradle") version "0.27.0"
+}
+
+repositories {
+    mavenCentral()
+}
+
+val libraryModules = setOf(
+    "core", "wire", "transport", "bytecode", "compiler", "proof", "ecdsa", "rsa", "merkle", "store", "state", "access", "gas", "tvm", "jit", "ope",
+    "p2p", "gossip", "consensus", "mint", "burn", "bips", "standards", "stake", "router", "did", "miner", "reflect", "twisto", "smartdoc",
+)
+
+val twistVersion = providers.gradleProperty("version").orElse("0.1.0-SNAPSHOT")
+
+allprojects {
+    group = "rip.crit"
+    version = twistVersion.get()
+}
+
+val moduleDependencies = mapOf(
+    "wire" to listOf("core", "p2p"),
+    "transport" to listOf("wire", "p2p", "core"),
+    "bytecode" to listOf("core"),
+    "compiler" to listOf("bytecode", "jit", "tvm"),
+    "proof" to listOf("core", "merkle"),
+    "ecdsa" to listOf("core"),
+    "rsa" to listOf("core"),
+    "merkle" to listOf("core"),
+    "store" to listOf("core"),
+    "state" to listOf("core"),
+    "access" to listOf("core"),
+    "tvm" to listOf("core", "gas", "state", "bytecode"),
+    "ope" to listOf("core", "tvm", "access"),
+    "p2p" to listOf("core"),
+    "gossip" to listOf("p2p"),
+    "consensus" to listOf("core"),
+    "mint" to listOf("core"),
+    "burn" to listOf("core"),
+    "bips" to listOf("core", "proof"),
+    "standards" to listOf("core", "store"),
+    "stake" to listOf("core", "store"),
+    "router" to listOf("core", "proof", "ecdsa", "p2p", "store"),
+    "did" to listOf("core", "p2p", "store"),
+    "miner" to listOf("core", "proof"),
+    "reflect" to listOf("core", "p2p", "store", "wire"),
+    "twisto" to listOf("core", "standards", "bips", "store", "compiler"),
+    "smartdoc" to listOf("core"),
+)
+
+ktfmt {
+    kotlinLangStyle() 
+}
+
+tasks.register<com.ncorti.ktfmt.gradle.tasks.KtfmtCheckTask>("fmtCheck") {
+    group = "verification"
+    source = project.fileTree(layout.projectDirectory.dir("app/src/main/kotlin")) {
+        include("**/*.kt")
+    }
+}
+
+tasks.register<com.ncorti.ktfmt.gradle.tasks.KtfmtFormatTask>("fmt") {
+    group = "formatting"
+    source = project.fileTree(layout.projectDirectory.dir("app/src/main/kotlin")) {
+        include("**/*.kt")
+    }
+}
+
+subprojects {
+    apply(plugin = "org.jetbrains.kotlin.jvm")
+
+    layout.buildDirectory.set(rootProject.layout.buildDirectory.dir("projects/${project.name}"))
+
+    repositories { mavenCentral() }
+
+    extensions.configure<KotlinJvmProjectExtension> {
+        jvmToolchain(25)
+        sourceSets.named("main") {
+            kotlin.srcDir(rootProject.file("app/src/main/kotlin"))
+            kotlin.include("rip/crit/twist/${project.name}/**")
+        }
+    }
+
+    tasks.withType<KotlinCompile>().configureEach {
+        compilerOptions.freeCompilerArgs.add("-Xjsr305=strict")
+    }
+}
+
+configure(subprojects.filter { it.name in libraryModules }) {
+    apply(plugin = "java-library")
+    apply(plugin = "maven-publish")
+
+    extensions.configure<org.gradle.api.plugins.JavaPluginExtension> {
+        withSourcesJar()
+        withJavadocJar()
+    }
+
+    dependencies {
+        moduleDependencies[name].orEmpty().forEach { dependency -> add("api", project(":$dependency")) }
+    }
+
+    extensions.configure<PublishingExtension> {
+        publications {
+            create<MavenPublication>("mavenJava") {
+                from(components["java"])
+                artifactId = "twist-${project.name}"
+                pom {
+                    name.set("Twist ${project.name}")
+                    description.set(project.description ?: "Twist ${project.name} library")
+                }
+            }
+        }
+        repositories {
+            maven {
+                name = "forgejo"
+                url = uri("https://ai.crit.rip/api/packages/jprims/maven")
+                credentials(PasswordCredentials::class) {
+                    username = providers.gradleProperty("forgejoUsername").orNull
+                    password = providers.gradleProperty("forgejoPassword").orNull
+                }
+                authentication {
+                    create<BasicAuthentication>("basic")
+                }
+            }
+        }
+    }
+}
+
+project(":app") {
+    apply(plugin = "application")
+    extensions.configure<KotlinJvmProjectExtension> {
+        sourceSets.named("main") { kotlin.include("rip/crit/twist/App.kt") }
+    }
+    dependencies {
+        libraryModules.forEach { dependency -> add("implementation", project(":$dependency")) }
+    }
+    extensions.configure<JavaApplication> {
+        mainClass.set("rip.crit.twist.AppKt")
+    }
+}
+
+project(":compiler-app") {
+    apply(plugin = "application")
+    extensions.configure<KotlinJvmProjectExtension> {
+        sourceSets.named("main") {
+            kotlin.setSrcDirs(listOf(rootProject.file("apps/compiler/src/main/kotlin")))
+            kotlin.setIncludes(emptySet())
+        }
+    }
+    dependencies { add("implementation", project(":compiler")) }
+    extensions.configure<JavaApplication> { mainClass.set("rip.crit.twist.tool.compiler.MainKt") }
+}
+
+fun configureTool(projectName: String, sourceDirectory: String, dependency: String, entryPoint: String) {
+    project(projectName) {
+        apply(plugin = "application")
+        extensions.configure<KotlinJvmProjectExtension> {
+            sourceSets.named("main") {
+                kotlin.setSrcDirs(listOf(rootProject.file(sourceDirectory)))
+                kotlin.setIncludes(emptySet())
+            }
+        }
+        dependencies { add("implementation", project(dependency)) }
+        extensions.configure<JavaApplication> { mainClass.set(entryPoint) }
+    }
+}
+
+configureTool(":miner-tool", "apps/miner/src/main/kotlin", ":miner", "rip.crit.twist.tool.miner.MainKt")
+project(":miner-tool") {
+    dependencies {
+        add("implementation", project(":stake"))
+        add("implementation", project(":store"))
+    }
+}
+configureTool(":reflect-tool", "apps/reflect/src/main/kotlin", ":reflect", "rip.crit.twist.tool.reflect.MainKt")
+configureTool(":twisto-tool", "apps/twisto/src/main/kotlin", ":twisto", "rip.crit.twist.tool.twisto.MainKt")
+configureTool(":docs-tool", "apps/docs/src/main/kotlin", ":smartdoc", "rip.crit.twist.tool.docs.MainKt")
--- a/gradle.properties
+++ b/gradle.properties
@ -0,0 +1,7 @@
+# This file was generated by the Gradle 'init' task.
+# https://docs.gradle.org/current/userguide/build_environment.html#sec:gradle_configuration_properties
+
+org.gradle.configuration-cache=true
+org.gradle.parallel=true
+org.gradle.caching=true
+
--- a/gradle/wrapper/gradle-wrapper.jar
+++ b/gradle/wrapper/gradle-wrapper.jar
--- a/Show more
+++ b/Show more
				`@ -0,0 +1 @@`
				`description = "SmartDoc static documentation generator"`
				`@ -0,0 +1 @@`
				`description = "Twist CPU miner command-line tool"`
				`@ -0,0 +1 @@`
				`description = "Twist network reflection command-line tool"`