Add basic support for wallet descriptors

build.gradle.kts

@@ -67,7 +67,7 @@ kotlin {
         }
 
         all {
-            languageSettings.useExperimentalAnnotation("kotlin.RequiresOptIn")
+            languageSettings.optIn("kotlin.RequiresOptIn")
         }
     }
 

src/commonMain/kotlin/fr/acinq/bitcoin/Block.kt

@@ -32,7 +32,6 @@ import kotlin.jvm.JvmStatic
  * @param bits              The calculated difficulty target being used for this block
  * @param nonce             The nonce used to generate this block… to allow variations of the header and compute different hashes
  */
-@OptIn(ExperimentalUnsignedTypes::class)
 public data class BlockHeader(
     @JvmField val version: Long,
     @JvmField val hashPreviousBlock: ByteVector32,
@@ -103,7 +102,6 @@ public data class BlockHeader(
         }
 
         @JvmStatic
-        @OptIn(ExperimentalUnsignedTypes::class)
         public fun getDifficulty(header: BlockHeader): UInt256 {
             val (diff, neg, _) = UInt256.decodeCompact(header.bits)
             return if (neg) -diff else diff
@@ -116,7 +114,6 @@ public data class BlockHeader(
          *         by bitcoin core
          */
         @JvmStatic
-        @OptIn(ExperimentalUnsignedTypes::class)
         public fun blockProof(bits: Long): UInt256 {
             val (target, negative, overflow) = UInt256.decodeCompact(bits)
             return if (target == UInt256.Zero || negative || overflow) UInt256.Zero else {
@@ -186,7 +183,6 @@ public object MerkleTree {
     }
 }
 
-@OptIn(ExperimentalUnsignedTypes::class, ExperimentalStdlibApi::class)
 public data class Block(@JvmField val header: BlockHeader, @JvmField val tx: List<Transaction>) {
     @JvmField
     val hash: ByteVector32 = header.hash

src/commonMain/kotlin/fr/acinq/bitcoin/BtcSerializer.kt

@@ -24,7 +24,6 @@ import fr.acinq.bitcoin.io.Output
 import fr.acinq.secp256k1.Hex
 import kotlin.jvm.JvmStatic
 
-@OptIn(ExperimentalUnsignedTypes::class)
 public abstract class BtcSerializer<T> {
     /**
      * write a message to a stream
@@ -196,7 +195,6 @@ public abstract class BtcSerializer<T> {
         }
 
         @JvmStatic
-        @OptIn(ExperimentalStdlibApi::class)
         public fun writeVarstring(input: String, out: Output) {
             writeVarint(input.length, out)
             writeBytes(input.encodeToByteArray(), out)

src/commonMain/kotlin/fr/acinq/bitcoin/Descriptor.kt

@@ -0,0 +1,93 @@
+package fr.acinq.bitcoin
+
+import fr.acinq.bitcoin.DeterministicWallet.derivePrivateKey
+import fr.acinq.bitcoin.DeterministicWallet.publicKey
+import kotlin.jvm.JvmStatic
+
+public object Descriptor {
+    private fun polyMod(cc: Long, value: Int): Long {
+        var c = cc
+        val c0 = c shr 35
+        c = ((c and 0x7ffffffffL) shl 5) xor value.toLong()
+        if ((c0 and 1L) != 0L) c = c xor 0xf5dee51989L
+        if ((c0 and 2L) != 0L) c = c xor 0xa9fdca3312L
+        if ((c0 and 4L) != 0L) c = c xor 0x1bab10e32dL
+        if ((c0 and 8L) != 0L) c = c xor 0x3706b1677aL
+        if ((c0 and 16L) != 0L) c = c xor 0x644d626ffdL
+        return c
+    }
+
+    @JvmStatic
+    public fun checksum(span: String): String {
+        /** A character set designed such that:
+         *  - The most common 'unprotected' descriptor characters (hex, keypaths) are in the first group of 32.
+         *  - Case errors cause an offset that's a multiple of 32.
+         *  - As many alphabetic characters are in the same group (while following the above restrictions).
+         *
+         * If p(x) gives the position of a character c in this character set, every group of 3 characters
+         * (a,b,c) is encoded as the 4 symbols (p(a) & 31, p(b) & 31, p(c) & 31, (p(a) / 32) + 3 * (p(b) / 32) + 9 * (p(c) / 32).
+         * This means that changes that only affect the lower 5 bits of the position, or only the higher 2 bits, will just
+         * affect a single symbol.
+         *
+         * As a result, within-group-of-32 errors count as 1 symbol, as do cross-group errors that don't affect
+         * the position within the groups.
+         */
+        val INPUT_CHARSET = "0123456789()[],'/*abcdefgh@:$%{}" + "IJKLMNOPQRSTUVWXYZ&+-.;<=>?!^_|~" + "ijklmnopqrstuvwxyzABCDEFGH`#\"\\ "
+
+        /** The character set for the checksum itself (same as bech32). */
+        val CHECKSUM_CHARSET = "qpzry9x8gf2tvdw0s3jn54khce6mua7l";
+
+        var c = 1L
+        var cls = 0
+        var clscount = 0
+        span.forEach { ch ->
+            val pos = INPUT_CHARSET.indexOf(ch);
+            if (pos == -1) return "";
+            c = polyMod(c, pos and 31); // Emit a symbol for the position inside the group, for every character.
+            cls = cls * 3 + (pos shr 5); // Accumulate the group numbers
+            clscount += 1
+            if (clscount == 3) {
+                // Emit an extra symbol representing the group numbers, for every 3 characters.
+                c = polyMod(c, cls)
+                cls = 0
+                clscount = 0
+            }
+        }
+        if (clscount > 0) c = polyMod(c, cls)
+        for (j in 0 until 8) c = polyMod(c, 0) // Shift further to determine the checksum.
+        c = c xor 1 // Prevent appending zeroes from not affecting the checksum.
+
+        val ret = StringBuilder("        ")
+        for (j in 0 until 8) {
+            val pos1 = (c shr (5 * (7 - j))) and 31
+            val char = CHECKSUM_CHARSET[pos1.toInt()]
+            ret[j] = char
+        }
+        return ret.toString()
+    }
+
+    private fun getBIP84KeyPath(chainHash: ByteVector32): Pair<String, Int> = when (chainHash) {
+        Block.RegtestGenesisBlock.hash, Block.TestnetGenesisBlock.hash -> "84'/1'/0'/0" to DeterministicWallet.tpub
+        Block.LivenetGenesisBlock.hash -> "84'/0'/0'/0" to DeterministicWallet.xpub
+        else -> error("invalid chain hash $chainHash")
+    }
+
+    @JvmStatic
+    public fun BIP84Descriptors(chainHash: ByteVector32, master: DeterministicWallet.ExtendedPrivateKey): Pair<String, String> {
+        val (keyPath, _) = getBIP84KeyPath(chainHash)
+        val accountPub = publicKey(derivePrivateKey(master, KeyPath(keyPath)))
+        val fingerprint = DeterministicWallet.fingerprint(master) and 0xFFFFFFFFL
+        return BIP84Descriptors(chainHash, fingerprint, accountPub)
+    }
+
+    @JvmStatic
+    public fun BIP84Descriptors(chainHash: ByteVector32, fingerprint: Long, accountPub: DeterministicWallet.ExtendedPublicKey): Pair<String, String> {
+        val (keyPath, prefix) = getBIP84KeyPath(chainHash)
+        val accountDesc = "wpkh([${fingerprint.toString(16)}/$keyPath]${DeterministicWallet.encode(accountPub, prefix)}/0/*)"
+        val changeDesc = "wpkh([${fingerprint.toString(16)}/$keyPath]${DeterministicWallet.encode(accountPub, prefix)}/1/*)"
+        return Pair(
+            "$accountDesc#${checksum(accountDesc)}",
+            "$changeDesc#${checksum(changeDesc)}"
+        )
+    }
+}

src/commonMain/kotlin/fr/acinq/bitcoin/DeterministicWallet.kt

@@ -27,7 +27,6 @@ import kotlin.jvm.JvmStatic
 /**
  * see https://github.com/bitcoin/bips/blob/master/bip-0032.mediawiki
  */
-@OptIn(ExperimentalUnsignedTypes::class)
 public object DeterministicWallet {
     public const val hardenedKeyIndex: Long = 0x80000000L
 

src/commonMain/kotlin/fr/acinq/bitcoin/Script.kt

@@ -25,7 +25,6 @@ import kotlin.jvm.JvmStatic
 
 public typealias RunnerCallback = (List<ScriptElt>, List<ByteVector>, Script.Runner.Companion.State) -> Boolean
 
-@OptIn(ExperimentalUnsignedTypes::class)
 public object Script {
     public const val MaxScriptElementSize: Int = 520
     public const val LockTimeThreshold: Long = 500000000L

src/commonMain/kotlin/fr/acinq/bitcoin/Transaction.kt

@@ -30,7 +30,6 @@ import kotlin.jvm.JvmStatic
  * @param hash  reversed sha256(sha256(tx)) where tx is the transaction we want to refer to
  * @param index index of the output in tx that we want to refer to
  */
-@OptIn(ExperimentalUnsignedTypes::class)
 public data class OutPoint(@JvmField val hash: ByteVector32, @JvmField val index: Long) : BtcSerializable<OutPoint> {
     public constructor(hash: ByteArray, index: Long) : this(hash.byteVector32(), index)
 
@@ -129,7 +128,6 @@ public data class ScriptWitness(@JvmField val stack: List<ByteVector>) : BtcSeri
  *                        information is updated before inclusion into a block. Repurposed for OP_CSV (see BIPs 68 & 112)
  * @param witness         Transaction witness (i.e. what is in sig script for standard transactions).
  */
-@OptIn(ExperimentalUnsignedTypes::class)
 public data class TxIn(
     @JvmField val outPoint: OutPoint,
     @JvmField val signatureScript: ByteVector,
@@ -212,7 +210,6 @@ public data class TxIn(
     override fun serializer(): BtcSerializer<TxIn> = TxIn
 }
 
-@OptIn(ExperimentalUnsignedTypes::class)
 public data class TxOut(@JvmField val amount: Satoshi, @JvmField val publicKeyScript: ByteVector) : BtcSerializable<TxOut> {
 
     public constructor(amount: Satoshi, publicKeyScript: ByteArray) : this(amount, publicKeyScript.byteVector())
@@ -259,7 +256,6 @@ public data class TxOut(@JvmField val amount: Satoshi, @JvmField val publicKeySc
     override fun serializer(): BtcSerializer<TxOut> = TxOut
 }
 
-@OptIn(ExperimentalUnsignedTypes::class)
 public data class Transaction(
     @JvmField val version: Long,
     @JvmField val txIn: List<TxIn>,

src/commonMain/kotlin/fr/acinq/bitcoin/io/ByteArrayOutput.kt

@@ -20,7 +20,6 @@ public class ByteArrayOutput : Output {
     private var array: ByteArray = ByteArray(32)
     private var position: Int = 0
 
-    @OptIn(ExperimentalStdlibApi::class)
     private fun ensureCapacity(elementsToAppend: Int) {
         if (position + elementsToAppend <= array.size) return
         val newArray = ByteArray((position + elementsToAppend).takeHighestOneBit() shl 1)

src/commonMain/kotlin/fr/acinq/bitcoin/psbt/Psbt.kt

@@ -30,7 +30,6 @@ import kotlin.jvm.JvmStatic
  * @param inputs signing data for each input of the transaction to be signed (order matches the unsigned tx).
  * @param outputs signing data for each output of the transaction to be signed (order matches the unsigned tx).
  */
-@OptIn(ExperimentalUnsignedTypes::class)
 public data class Psbt(val global: Global, val inputs: List<Input>, val outputs: List<Output>) {
 
     init {

src/commonTest/kotlin/fr/acinq/bitcoin/Base58TestsCommon.kt

@@ -19,7 +19,6 @@ package fr.acinq.bitcoin
 import kotlin.test.Test
 import kotlin.test.assertEquals
 
-@OptIn(ExperimentalStdlibApi::class)
 class Base58TestsCommon {
     @Test
     fun `basic encode-decode tests`() {

src/commonTest/kotlin/fr/acinq/bitcoin/DescriptorTestsCommon.kt

@@ -0,0 +1,34 @@
+package fr.acinq.bitcoin
+
+import kotlin.test.Test
+import kotlin.test.assertEquals
+
+class DescriptorTestsCommon {
+    @Test
+    fun `compute descriptor checksums`() {
+        val data = listOf(
+            "pkh([6ded4eb8/44h/0h/0h]xpub6C6N5WVF5zmurBR52MZZj8Jxm6eDiKyM4wFCm7xTYBEsAvJPqBKp2u2K7RTsZaYDN8duBWq4acrD4vrwjaKHTYuntGjL334nVHtLNuaj5Mu/0/*)#5mzpq0w6",
+            "wpkh([6ded4eb8/84h/0h/0h]xpub6CDeom4xT3Wg7BuyXU2Sd9XerTKttyfxRwJE36mi5HxFYpYdtdwM76Zx8swPnc6zxuArMYJgjNy91fJ13YtGPHgf49YqA8KdXg6D69tzNFh/0/*)#refya6f0",
+            "sh(wpkh([6ded4eb8/49h/0h/0h]xpub6Cb8jR9kYsfC6kj9CsE18SyudWjW2V3FnBFkT2oqq6n7NWWvJrjhFin3sAYg8X7ApX8iPophBa98mo4nMvSxnqrXvpnwaRopecQz859Ai1s/0/*))#xrhyhtvl",
+            "tr([6ded4eb8/86h/0h/0h]xpub6CDp1iw76taes3pkqfiJ6PYhwURkaYksJ62CrrdTVr6ow9wR9mKAtUGoZQqb8pRDiq2F8k31tYrrJjVGTRSLYGQ7nYpmewH94ThsAgDxJ4h/0/*)#2nm7drky",
+            "pkh([6ded4eb8/44h/0h/0h]xpub6C6N5WVF5zmurBR52MZZj8Jxm6eDiKyM4wFCm7xTYBEsAvJPqBKp2u2K7RTsZaYDN8duBWq4acrD4vrwjaKHTYuntGjL334nVHtLNuaj5Mu/1/*)#908qa67z",
+            "wpkh([6ded4eb8/84h/0h/0h]xpub6CDeom4xT3Wg7BuyXU2Sd9XerTKttyfxRwJE36mi5HxFYpYdtdwM76Zx8swPnc6zxuArMYJgjNy91fJ13YtGPHgf49YqA8KdXg6D69tzNFh/1/*)#jdv9q0eh",
+            "sh(wpkh([6ded4eb8/49h/0h/0h]xpub6Cb8jR9kYsfC6kj9CsE18SyudWjW2V3FnBFkT2oqq6n7NWWvJrjhFin3sAYg8X7ApX8iPophBa98mo4nMvSxnqrXvpnwaRopecQz859Ai1s/1/*))#nzej05eq",
+            "tr([6ded4eb8/86h/0h/0h]xpub6CDp1iw76taes3pkqfiJ6PYhwURkaYksJ62CrrdTVr6ow9wR9mKAtUGoZQqb8pRDiq2F8k31tYrrJjVGTRSLYGQ7nYpmewH94ThsAgDxJ4h/1/*)#m87lskxu"
+        )
+        data.forEach { dnc ->
+            val (desc, checksum) = dnc.split('#').toTypedArray()
+            assertEquals(checksum, Descriptor.checksum(desc))
+       }
+    }
+
+    @Test
+    fun `compute BIP84 descriptors`() {
+        val seed = ByteVector.fromHex("817a9c8e6ba36f083d7e68b5ee89ce74fde9ef294a724a5efc5cef2b88db057f")
+        val master = DeterministicWallet.generate(seed)
+        val (accountDesc, changeDesc) = Descriptor.BIP84Descriptors(Block.RegtestGenesisBlock.hash, master)
+        assertEquals("wpkh([189ef5fe/84'/1'/0'/0]tpubDFTu6FhLqfTBLMd7BvGkyH1h4XBw7XoKWfnNNWw5Sp8V6aC55EhgPTVNAYvBwBXQ8EGnMqaZi3dpdSzhMbD4Z7ivZiaVKNMUkXVjDU1CDuE/0/*)#uysr3s9y", accountDesc)
+        assertEquals("wpkh([189ef5fe/84'/1'/0'/0]tpubDFTu6FhLqfTBLMd7BvGkyH1h4XBw7XoKWfnNNWw5Sp8V6aC55EhgPTVNAYvBwBXQ8EGnMqaZi3dpdSzhMbD4Z7ivZiaVKNMUkXVjDU1CDuE/1/*)#ds4zv94u", changeDesc)
+    }
+
+}

src/commonTest/kotlin/fr/acinq/bitcoin/crypto/Ripemd160TestsCommon.kt

@@ -20,7 +20,6 @@ import fr.acinq.secp256k1.Hex
 import kotlin.test.Test
 import kotlin.test.assertTrue
 
-@OptIn(ExperimentalStdlibApi::class)
 class Ripemd160TestsCommon {
     @Test // from https://homes.esat.kuleuven.be/~bosselae/ripemd160.html
     fun `reference tests`() {

src/commonTest/kotlin/fr/acinq/bitcoin/crypto/Sha1TestsCommon.kt

@@ -20,7 +20,6 @@ import fr.acinq.secp256k1.Hex
 import kotlin.test.Test
 import kotlin.test.assertTrue
 
-@OptIn(ExperimentalStdlibApi::class)
 class Sha1TestsCommon {
     val testVectors = arrayOf(
         "" to "da39a3ee5e6b4b0d3255bfef95601890afd80709",

src/commonTest/kotlin/fr/acinq/bitcoin/crypto/Sha512TestsCommon.kt

@@ -20,7 +20,6 @@ import fr.acinq.secp256k1.Hex
 import kotlin.test.Test
 import kotlin.test.assertTrue
 
-@OptIn(ExperimentalStdlibApi::class)
 class Sha512TestsCommon {
     @Test
     fun `reference tests`() {