Merge pull request #6 from jeton-tech/price

threshold module and example

examples/threshold.js

@@ -0,0 +1,116 @@
+const jeton = require('../index')
+const PrivateKey = jeton.PrivateKey
+const ThresholdMessage = jeton.threshold.Message
+const OutputScript = jeton.threshold.OutputScript
+const Transaction = jeton.Transaction
+const Signature = jeton.Signature
+
+// Create keypairs for 2 players and an oracle
+const priv1 = new PrivateKey("KzwmMwHjbmRRdtwVUowKpYmpnJmMaVyGTwYLmh2qmiWcqgd7W9fG")
+const pub1 = priv1.toPublicKey()
+const priv2 = new PrivateKey("KzyhHmmxwFbv2Mo8bQsJQwXhrCgAtjsCmuqBBmGZrcjfTn1Xvzw1")
+const pub2 = priv2.toPublicKey()
+
+var utxoForPub2 = new Transaction.UnspentOutput({ 
+    txid:
+    'b2b671f0cb3d7710b5d8a8420fff14b18173de876da710438dafa0ae6e8f5357',
+    vout: 1,
+    satoshis: 10200,
+    scriptPubKey: '76a9149383fa6588a176c2592cb2f4008d779293246adb88ac' 
+})
+
+var utxoForPub1 = new Transaction.UnspentOutput({ 
+    txid:
+    'ee874221a431cf09d3373c4b9ffbb1e8fe80526d4304695e2f97541fc084c8f4',
+    vout: 1,
+    satoshis: 10200,
+    scriptPubKey: '76a914b011100d12d0537232692b3c113be5a8f505395588ac' 
+})
+
+// Create array of UTXO arrays
+var splitUtxos = [utxoForPub1, utxoForPub2]
+
+const oraclePriv = new PrivateKey('L5FDo3MEb2QNs2aQJ5DVGSDE5eBzVsgZny15Ri649RjysWAeLkTs')
+const oraclePub = oraclePriv.toPublicKey();
+console.log('user 1 pubkey', pub1.toString())
+console.log('user 2 pubkey', pub2.toString())
+console.log('oracle pubkey', oraclePub.toString())
+
+const blockheight = 660211
+const price = 220.2098
+
+// This is the ASM for the redeem script if done in CashScript
+// 0556 f2120a 029207e74ee73342f9af30859c03f684da444344d957a949c768316519f9df6a36 02c3e42dd2a3806f1bc9a9f32c3a97b872ed03ce8a779242b8bf2dba636ce655b0 OP_6 OP_PICK OP_4 OP_SPLIT OP_DROP OP_BIN2NUM OP_7 OP_PICK OP_4 OP_SPLIT OP_NIP OP_BIN2NUM OP_OVER OP_5 OP_ROLL OP_GREATERTHANOREQUAL OP_VERIFY OP_SWAP OP_CHECKLOCKTIMEVERIFY OP_DROP OP_3 OP_ROLL OP_GREATERTHANOREQUAL OP_VERIFY OP_3 OP_ROLL OP_4 OP_ROLL OP_3 OP_ROLL OP_CHECKDATASIGVERIFY OP_CHECKSIG
+
+let message = new ThresholdMessage(blockheight, price).message
+console.log('message', message)
+let oracleSig = Signature.signCDS(message, oraclePriv)
+// console.log('sig DER', oracleSig.toDER())
+let verify = ThresholdMessage.verifySignature(message, oracleSig, oraclePub)
+// console.log('signature verified?', verify)
+
+// Create the output script
+var outputScriptData = {
+    threshold: 218,
+    blockheight: blockheight,
+    oraclePubKey: oraclePub,
+    parties: {
+        gt: {pubKey: pub1},
+        lte: {pubKey: pub2}
+    }
+}
+
+outScript = new OutputScript(outputScriptData)
+
+let outputScript = outScript.toScript()
+
+// console.log(outputScript)
+
+let outScriptHex = outScript.toScript().toHex()
+
+// console.log('destination P2SH', outScript.toAddress())
+
+// Set miner fee and total amount to send (will be split between UTXOs from useUTXOs array)
+var splitUtxoMinerFee = 200
+var amountToSend = 20000
+
+var splitTxSendAmount = (amountToSend / splitUtxos.length)
+
+// Create two separate transactions from players 2 and 3 to fund the escrow
+var sighash = (Signature.SIGHASH_ALL | Signature.SIGHASH_FORKID | Signature.SIGHASH_ANYONECANPAY)
+var txArray = []
+for (let i = 0; i < splitUtxos.length; i++) {
+    txArray[i] = new Transaction()
+        .from(splitUtxos[i])          // Feed information about what unspent outputs one can use
+        .toP2SH(outScript, amountToSend)
+        .sign([priv1, priv2], sighash)     // Signs all the inputs it can
+}
+
+// Combine the transactions by merging the inputs
+var fundTx = Transaction.mergeTransactionInputs(txArray)
+
+// var itx = new Transaction(fundTx.toString())
+
+// console.log('fundTx', itx.toObject())
+
+// Now spend the escrow transaction...
+
+var escrowUtxo = Transaction.utxoFromTxOutput(fundTx, 0)
+
+// Make Transaction from escrow UTXO
+sighash = (Signature.SIGHASH_ALL | Signature.SIGHASH_FORKID)
+
+var spendTx = new Transaction()
+.from(escrowUtxo)
+.to(priv1.toAddress(), 19000)
+.lockUntilBlockHeight(660211) // Must be after the blockheight in the script
+
+//console.log(spendTx.toObject())
+
+// Sign CDS input at index 0 as player 2
+spendTx.signThreshold(0, priv1, message, oracleSig, outScript.toScript(), sighash)
+
+// console.log(spendTx.toObject())
+console.log('estimated size', spendTx._estimateSize())
+console.log('verify tx full sig', spendTx.verify())
+console.log('jeton signature verified?', spendTx.verifyScriptSig(0))

index.js

@@ -13,4 +13,9 @@ jeton.escrow = {}
 jeton.escrow.InputScript = require('./lib/escrow/InputScript')
 jeton.escrow.OutputScript = require('./lib/escrow/OutputScript')
 
+// Threshold
+jeton.threshold = require('./lib/threshold')
+//jeton.escrow.InputScript = require('./lib/escrow/InputScript')
+//jeton.escrow.OutputScript = require('./lib/escrow/OutputScript')
+
 module.exports = jeton

lib/Transaction.js

@@ -7,9 +7,11 @@ const Sighash = Transaction.Sighash
 const BN = bitcore.crypto.BN
 const Signature = require('./Signature')
 const InputScript = require('./escrow/InputScript')
+const ThresholdInputScript = require('./threshold/InputScript')
 
 
 Transaction.P2SHFlags = Interpreter.SCRIPT_VERIFY_P2SH 
+    | Interpreter.SCRIPT_VERIFY_CHECKLOCKTIMEVERIFY
     | Interpreter.SCRIPT_ENABLE_SIGHASH_FORKID
     | Interpreter.SCRIPT_ENABLE_CHECKDATASIG 
     | Interpreter.SCRIPT_VERIFY_STRICTENC 
@@ -75,6 +77,43 @@ Transaction.prototype.signEscrow = function (inputIndex, winnerPrivKey, refMsg,
 }
 
 
+/**
+ * Signs an threshold escrow transaction as defined in jeton.threshold.OutputScript
+ *
+ * @param {number} inputIndex - index of the input to sign
+ * @param {PrivateKey} winnerPrivKey - the private key of the escrow beneficiary
+ * @param {string} oracleMsg - the message for the outcome
+ * @param {Signature} oracleSig - the signature for the message and referee public key
+ * @param {Script} subscript - the non-P2SH (original) scriptPubKey
+ * @param {number} sighash - the type of signature
+ * 
+ * @returns {Transaction}
+ */
+Transaction.prototype.signThreshold = function (inputIndex, winnerPrivKey, oracleMsg, oracleSig, subscript, sighash) {
+    sighash = sighash || (Signature.SIGHASH_ALL | Signature.SIGHASH_FORKID)
+
+    let input = this.toObject()['inputs'][inputIndex]
+    let p2pkhSig = Sighash.sign(this, winnerPrivKey, sighash, inputIndex, subscript, BN.fromNumber(input.output.satoshis), Transaction.P2SHFlags)
+
+    let winnerScript = Script.buildPublicKeyHashIn(winnerPrivKey.toPublicKey(), p2pkhSig, sighash)
+
+    // Generate scriptSig
+    let inputScriptData = {
+        oracleSig: oracleSig,
+        message: oracleMsg,
+        winnerScript: winnerScript,
+        outputScript: subscript
+    }
+
+    inScript = new ThresholdInputScript(inputScriptData)
+
+    // Set scriptSig for inputIndex
+    this.inputs[inputIndex].setScript(inScript.toScript())
+
+    return this
+}
+
+
 /**
  * Verify that a P2SH input is properly signed
  *

lib/threshold/InputScript.js

@@ -0,0 +1,50 @@
+const bitcore = require('bitcore-lib-cash')
+const Hash = bitcore.crypto.Hash
+const Script = bitcore.Script
+const PublicKey = bitcore.PublicKey
+
+
+/**
+ * Instantiate an object to create escrow scriptSig
+ *
+ * @param {object} data - The encoded data in various formats
+ * @param {Signature} data.oracleSig
+ * @param {Buffer} data.message
+ * @param {Script} data.winnerScript - a P2PKH scriptSig for the transaction signed by escrow beneficiary
+ * @param {Script} data.outputScript - The original (non-P2SH) scriptPubKey for this input
+ * 
+ * @constructor
+ */
+var InputScript = function (data) {
+
+    this.oracleSig = data.oracleSig
+    this.message = data.message
+    this.winnerScript = data.winnerScript
+    this.outputScript = data.outputScript
+}
+
+
+/**
+ * @returns {Script}
+ */
+InputScript.prototype.toScript = function () {
+    let outputBuf = this.outputScript.toBuffer()
+    let inScript = Script()
+    .add(this.winnerScript)
+    .add(this.oracleSig.toBuffer())
+    .add(this.message)
+    .add(outputBuf)
+
+    return inScript
+}
+
+
+/**
+ * @returns {Buffer}
+ */
+InputScript.prototype.toBuffer = function () {
+    let outScript = this.toScript()
+    return outScript.toBuffer()
+}
+
+module.exports = InputScript

lib/threshold/Message.js

@@ -0,0 +1,47 @@
+const bitcore = require('bitcore-lib-cash')
+const Address = bitcore.Address
+const Hash = bitcore.crypto.Hash
+const ECDSA = bitcore.crypto.ECDSA
+const Signature = bitcore.crypto.Signature
+const Script = bitcore.Script
+const PrivateKey = bitcore.PrivateKey
+const PublicKey = bitcore.PublicKey
+const ScriptNumber = require('./ScriptNumber')
+
+var Message = function (blockHeight, thresholdValue) {
+
+    this.blockHeight = blockHeight
+    this.threshold = Math.ceil(thresholdValue)
+    this.message = this.createMessage()
+}
+
+/**
+ * Encode a blockHeight and threshold amount into a byte sequence of 8 bytes (4 bytes per value)
+ * This is compatible with the CashScript PriceOracle.ts
+ * https://github.com/Bitcoin-com/cashscript/blob/master/examples/PriceOracle.ts
+ * 
+ * 
+ */
+Message.prototype.createMessage = function () {
+    const lhs = Buffer.alloc(4, 0);
+    const rhs = Buffer.alloc(4, 0);
+    ScriptNumber.encode(this.blockHeight).copy(lhs);
+    ScriptNumber.encode(this.threshold).copy(rhs);
+    console.log('decoded price', ScriptNumber.decode(rhs, 4, false))
+    console.log('decoded threshold', ScriptNumber.decode(lhs, 4, false))
+    return Buffer.concat([lhs, rhs]);
+}
+
+Message.signMessage = function(message, privkey){
+    return new ECDSA().set({
+        hashbuf: Hash.sha256(message),
+        privkey: privkey
+      }).signRandomK().sig;
+}
+
+Message.verifySignature = function(message, sig, pubkey) {
+    let msgHash = Hash.sha256(message)
+    return ECDSA.verify(msgHash, sig, pubkey)
+}
+
+module.exports = Message