Segregated Witness Support - WIP

.gitignore

@@ -1,3 +1,5 @@
 bitcoin.js
 coverage
 node_modules
+
+_dev.*.js

src/address.js

@@ -6,30 +6,54 @@ var types = require('./types')
 
 function fromBase58Check (address) {
   var payload = bs58check.decode(address)
-  if (payload.length < 21) throw new TypeError(address + ' is too short')
-  if (payload.length > 21) throw new TypeError(address + ' is too long')
 
   var version = payload[0]
   var hash = payload.slice(1)
+  var segWitVersion
+  var segWitPadding
 
-  return { hash: hash, version: version }
+  if (hash.length === 22 || hash.length === 34) {
+    segWitVersion = hash.readUInt8(0)
+    segWitPadding = hash.readUInt8(1)
+    hash = hash.slice(2)
+
+    if (segWitVersion > 16 || segWitPadding !== 0) {
+      throw new Error(address + ' has the length of a segWit address, but is not a valid segWit address')
+    }
+  } else if (hash.length > 20) throw new Error(address + ' is too long')
+  else if (hash.length < 20) throw new Error(address + ' is too short')
+
+  return { hash: hash, version: version, segWitVersion: segWitVersion }
 }
 
 function fromOutputScript (scriptPubKey, network) {
   network = network || networks.bitcoin
 
   if (bscript.isPubKeyHashOutput(scriptPubKey)) return toBase58Check(bscript.compile(scriptPubKey).slice(3, 23), network.pubKeyHash)
   if (bscript.isScriptHashOutput(scriptPubKey)) return toBase58Check(bscript.compile(scriptPubKey).slice(2, 22), network.scriptHash)
+  if (bscript.isSegWitPubKeyHashOutput(scriptPubKey)) return toBase58Check(bscript.compile(scriptPubKey).slice(2, 22), network.segWitPubKeyHash, 0)
+  if (bscript.isSegWitScriptHashOutput(scriptPubKey)) return toBase58Check(bscript.compile(scriptPubKey).slice(2, 34), network.segWitScriptHash, 0)
 
   throw new Error(bscript.toASM(scriptPubKey) + ' has no matching Address')
 }
 
-function toBase58Check (hash, version) {
-  typeforce(types.tuple(types.Hash160bit, types.UInt8), arguments)
+function toBase58Check (hash, version, segWitVersion) {
+  var payload
+  var isSegWit = typeof segWitVersion !== 'undefined'
 
-  var payload = new Buffer(21)
-  payload.writeUInt8(version, 0)
-  hash.copy(payload, 1)
+  typeforce(types.tuple((isSegWit ? types.oneOf(types.Hash160bit, types.Hash256bit) : types.Hash160bit), types.UInt8, types.maybe(types.UInt8)), arguments)
+
+  if (isSegWit) {
+    payload = new Buffer(3 + hash.length) // dynamic size based on hash because of difference between P2WPKH and P2WSH
+    payload.writeUInt8(version, 0)
+    payload.writeUInt8(segWitVersion, 1)
+    payload.writeUInt8(0, 2) // padding byte to make pretty prefixes
+    hash.copy(payload, 3)
+  } else {
+    payload = new Buffer(21)
+    payload.writeUInt8(version, 0)
+    hash.copy(payload, 1)
+  }
 
   return bs58check.encode(payload)
 }
@@ -38,8 +62,23 @@ function toOutputScript (address, network) {
   network = network || networks.bitcoin
 
   var decode = fromBase58Check(address)
+
   if (decode.version === network.pubKeyHash) return bscript.pubKeyHashOutput(decode.hash)
   if (decode.version === network.scriptHash) return bscript.scriptHashOutput(decode.hash)
+  if (decode.version === network.segWitPubKeyHash) {
+    if (decode.segWitVersion === 0) {
+      if (decode.hash.length === 20) {
+        return bscript.segWitPubKeyHashOutput(decode.hash)
+      }
+    }
+  }
+  if (decode.version === network.segWitScriptHash) {
+    if (decode.segWitVersion === 0) {
+      if (decode.hash.length === 32) {
+        return bscript.segWitScriptHashOutput(decode.hash)
+      }
+    }
+  }
 
   throw new Error(address + ' has no matching Script')
 }

src/bufferwriter.js

@@ -0,0 +1,55 @@
+var bufferutils = require('./bufferutils')
+var typeforce = require('typeforce')
+var types = require('./types')
+
+var BufferWriter = function (length) {
+  typeforce(types.tuple(types.Number), arguments)
+  this.buffer = new Buffer(length)
+  this.offset = 0
+}
+
+BufferWriter.prototype.writeSlice = function (slice) {
+  slice.copy(this.buffer, this.offset)
+  this.offset += slice.length
+
+  return this
+}
+
+BufferWriter.prototype.writeSliceWithVarInt = function (script) {
+  this.writeVarInt(script.length)
+  this.writeSlice(script)
+
+  return this
+}
+
+BufferWriter.prototype.writeScript = BufferWriter.prototype.writeSliceWithVarInt
+
+BufferWriter.prototype.writeInt = function (i) {
+  this.buffer.writeUInt8(i, this.offset)
+  this.offset += 1
+
+  return this
+}
+
+BufferWriter.prototype.writeUInt64 = function (i) {
+  bufferutils.writeUInt64LE(this.buffer, i, this.offset)
+  this.offset += 8
+
+  return this
+}
+
+BufferWriter.prototype.writeUInt32 = function (i) {
+  this.buffer.writeUInt32LE(i, this.offset)
+  this.offset += 4
+
+  return this
+}
+
+BufferWriter.prototype.writeVarInt = function (i) {
+  var n = bufferutils.writeVarInt(this.buffer, i, this.offset)
+  this.offset += n
+
+  return this
+}
+
+module.exports = BufferWriter

src/networks.js

@@ -10,6 +10,8 @@ module.exports = {
     },
     pubKeyHash: 0x00,
     scriptHash: 0x05,
+    segWitPubKeyHash: 0x06,
+    segWitScriptHash: 0x0A,
     wif: 0x80,
     dustThreshold: 546 // https://github.com/bitcoin/bitcoin/blob/v0.9.2/src/core.h#L151-L162
   },
@@ -21,9 +23,24 @@ module.exports = {
     },
     pubKeyHash: 0x6f,
     scriptHash: 0xc4,
+    segWitPubKeyHash: 0x03,
+    segWitScriptHash: 0x28,
     wif: 0xef,
     dustThreshold: 546
   },
+  segnet: {
+    messagePrefix: '\x18Bitcoin Signed Message:\n',
+    bip32: {
+      public: 0x053587CF,
+      private: 0x05358394
+    },
+    pubKeyHash: 0x1e,
+    scriptHash: 0x32,
+    segWitPubKeyHash: 0x03,
+    segWitScriptHash: 0x28,
+    wif: 0x9e,
+    dustThreshold: 546
+  },
   litecoin: {
     messagePrefix: '\x19Litecoin Signed Message:\n',
     bip32: {

src/script.js

@@ -166,6 +166,13 @@ function isPubKeyHashOutput (script) {
     buffer[24] === OPS.OP_CHECKSIG
 }
 
+function isSegWitPubKeyHashOutput (script) {
+  var buffer = compile(script)
+
+  return buffer.length === 22 &&
+      buffer[0] === OPS.OP_0
+}
+
 function isPubKeyInput (script) {
   var chunks = decompile(script)
 
@@ -194,7 +201,14 @@ function isScriptHashInput (script, allowIncomplete) {
   // is redeemScript a valid script?
   if (redeemScriptChunks.length === 0) return false
 
-  return classifyInput(scriptSigChunks, allowIncomplete) === classifyOutput(redeemScriptChunks)
+  var inputType = classifyInput(scriptSigChunks, allowIncomplete)
+  var outputType = classifyOutput(redeemScriptChunks)
+
+  if (outputType === 'segwitpubkeyhash') {
+    return inputType === 'pubkeyhash'
+  }
+
+  return inputType === outputType
 }
 
 function isScriptHashOutput (script) {
@@ -206,6 +220,13 @@ function isScriptHashOutput (script) {
     buffer[22] === OPS.OP_EQUAL
 }
 
+function isSegWitScriptHashOutput (script) {
+  var buffer = compile(script)
+
+  return buffer.length === 34 &&
+    buffer[0] === OPS.OP_0
+}
+
 // allowIncomplete is to account for combining signatures
 // See https://github.com/bitcoin/bitcoin/blob/f425050546644a36b0b8e0eb2f6934a3e0f6f80f/src/script/sign.cpp#L195-L197
 function isMultisigInput (script, allowIncomplete) {
@@ -257,6 +278,10 @@ function classifyOutput (script) {
     return 'pubkeyhash'
   } else if (isScriptHashOutput(chunks)) {
     return 'scripthash'
+  } else if (isSegWitPubKeyHashOutput(chunks)) {
+    return 'segwitpubkeyhash'
+  } else if (isSegWitScriptHashOutput(chunks)) {
+    return 'segwitscripthash'
   } else if (isMultisigOutput(chunks)) {
     return 'multisig'
   } else if (isPubKeyOutput(chunks)) {
@@ -297,6 +322,20 @@ function pubKeyHashOutput (pubKeyHash) {
   return compile([OPS.OP_DUP, OPS.OP_HASH160, pubKeyHash, OPS.OP_EQUALVERIFY, OPS.OP_CHECKSIG])
 }
 
+// OP_0 PUSH[{20-byte pubKeyHash}]
+function segWitPubKeyHashOutput (pubKeyHash) {
+  typeforce(types.Hash160bit, pubKeyHash)
+
+  return compile([OPS.OP_0, pubKeyHash])
+}
+
+// OP_0 PUSH[{32-byte scriptHash}}]
+function segWitScriptHashOutput (scriptHash) {
+  typeforce(types.Hash256bit, scriptHash)
+
+  return compile([OPS.OP_0, scriptHash])
+}
+
 // OP_HASH160 {scriptHash} OP_EQUAL
 function scriptHashOutput (scriptHash) {
   typeforce(types.Hash160bit, scriptHash)
@@ -379,18 +418,22 @@ module.exports = {
   isDefinedHashType: isDefinedHashType,
   isPubKeyHashInput: isPubKeyHashInput,
   isPubKeyHashOutput: isPubKeyHashOutput,
+  isSegWitPubKeyHashOutput: isSegWitPubKeyHashOutput,
   isPubKeyInput: isPubKeyInput,
   isPubKeyOutput: isPubKeyOutput,
   isScriptHashInput: isScriptHashInput,
   isScriptHashOutput: isScriptHashOutput,
+  isSegWitScriptHashOutput: isSegWitScriptHashOutput,
   isMultisigInput: isMultisigInput,
   isMultisigOutput: isMultisigOutput,
   isNullDataOutput: isNullDataOutput,
   classifyOutput: classifyOutput,
   classifyInput: classifyInput,
   pubKeyOutput: pubKeyOutput,
   pubKeyHashOutput: pubKeyHashOutput,
+  segWitPubKeyHashOutput: segWitPubKeyHashOutput,
   scriptHashOutput: scriptHashOutput,
+  segWitScriptHashOutput: segWitScriptHashOutput,
   multisigOutput: multisigOutput,
   pubKeyInput: pubKeyInput,
   pubKeyHashInput: pubKeyHashInput,