113 lines
3.7 KiB
JavaScript
113 lines
3.7 KiB
JavaScript
/* global describe, it */
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var assert = require('assert')
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var async = require('async')
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var bigi = require('bigi')
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var bitcoin = require('../../')
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var blockchain = require('./_blockchain')
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var ecurve = require('ecurve')
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var secp256k1 = ecurve.getCurveByName('secp256k1')
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describe('bitcoinjs-lib (crypto)', function () {
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it('can recover a private key from duplicate R values', function (done) {
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this.timeout(30000)
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var inputs = [
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{
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txId: 'f4c16475f2a6e9c602e4a287f9db3040e319eb9ece74761a4b84bc820fbeef50',
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vout: 0
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},
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{
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txId: 'f4c16475f2a6e9c602e4a287f9db3040e319eb9ece74761a4b84bc820fbeef50',
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vout: 1
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}
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]
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var txIds = inputs.map(function (x) { return x.txId })
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// first retrieve the relevant transactions
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blockchain.m.transactions.get(txIds, function (err, results) {
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assert.ifError(err)
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var transactions = {}
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results.forEach(function (tx) {
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transactions[tx.txId] = bitcoin.Transaction.fromHex(tx.txHex)
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})
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var tasks = []
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// now we need to collect/transform a bit of data from the selected inputs
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inputs.forEach(function (input) {
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var transaction = transactions[input.txId]
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var script = transaction.ins[input.vout].script
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var scriptChunks = bitcoin.script.decompile(script)
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assert(bitcoin.script.pubKeyHash.input.check(scriptChunks), 'Expected pubKeyHash script')
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var prevOutTxId = new Buffer(transaction.ins[input.vout].hash).reverse().toString('hex')
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var prevVout = transaction.ins[input.vout].index
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tasks.push(function (callback) {
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blockchain.m.transactions.get(prevOutTxId, function (err, result) {
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if (err) return callback(err)
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var prevOut = bitcoin.Transaction.fromHex(result.txHex)
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var prevOutScript = prevOut.outs[prevVout].script
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var scriptSignature = bitcoin.ECSignature.parseScriptSignature(scriptChunks[0])
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var publicKey = bitcoin.ECPair.fromPublicKeyBuffer(scriptChunks[1])
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var m = transaction.hashForSignature(input.vout, prevOutScript, scriptSignature.hashType)
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assert(publicKey.verify(m, scriptSignature.signature), 'Invalid m')
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// store the required information
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input.signature = scriptSignature.signature
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input.z = bigi.fromBuffer(m)
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return callback()
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})
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})
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})
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// finally, run the tasks, then on to the math
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async.parallel(tasks, function (err) {
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if (err) throw err
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var n = secp256k1.n
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for (var i = 0; i < inputs.length; ++i) {
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for (var j = i + 1; j < inputs.length; ++j) {
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var inputA = inputs[i]
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var inputB = inputs[j]
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// enforce matching r values
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assert.strictEqual(inputA.signature.r.toString(), inputB.signature.r.toString())
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var r = inputA.signature.r
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var rInv = r.modInverse(n)
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var s1 = inputA.signature.s
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var s2 = inputB.signature.s
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var z1 = inputA.z
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var z2 = inputB.z
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var zz = z1.subtract(z2).mod(n)
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var ss = s1.subtract(s2).mod(n)
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// k = (z1 - z2) / (s1 - s2)
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// d1 = (s1 * k - z1) / r
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// d2 = (s2 * k - z2) / r
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var k = zz.multiply(ss.modInverse(n)).mod(n)
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var d1 = ((s1.multiply(k).mod(n)).subtract(z1).mod(n)).multiply(rInv).mod(n)
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var d2 = ((s2.multiply(k).mod(n)).subtract(z2).mod(n)).multiply(rInv).mod(n)
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// enforce matching private keys
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assert.strictEqual(d1.toString(), d2.toString())
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}
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}
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done()
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})
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})
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})
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})
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