Daniel Cousens
8 years ago
committed by
Daniel Cousens
3 changed files with 62 additions and 52 deletions
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/* global describe, it */ |
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var assert = require('assert') |
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var bigi = require('bigi') |
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var bitcoin = require('../../') |
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var crypto = require('crypto') |
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var ecurve = require('ecurve') |
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var secp256k1 = ecurve.getCurveByName('secp256k1') |
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describe('bitcoinjs-lib (BIP32)', function () { |
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it('can recover a BIP32 parent private key from the parent public key, and a derived, non-hardened child private key', function () { |
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function recoverParent (master, child) { |
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assert(!master.keyPair.d, 'You already have the parent private key') |
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assert(child.keyPair.d, 'Missing child private key') |
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var curve = secp256k1 |
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var QP = master.keyPair.Q |
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var serQP = master.keyPair.getPublicKeyBuffer() |
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var d1 = child.keyPair.d |
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var d2 |
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var data = new Buffer(37) |
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serQP.copy(data, 0) |
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// search index space until we find it
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for (var i = 0; i < bitcoin.HDNode.HIGHEST_BIT; ++i) { |
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data.writeUInt32BE(i, 33) |
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// calculate I
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var I = crypto.createHmac('sha512', master.chainCode).update(data).digest() |
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var IL = I.slice(0, 32) |
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var pIL = bigi.fromBuffer(IL) |
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// See hdnode.js:273 to understand
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d2 = d1.subtract(pIL).mod(curve.n) |
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var Qp = new bitcoin.ECPair(d2).Q |
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if (Qp.equals(QP)) break |
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} |
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var node = new bitcoin.HDNode(new bitcoin.ECPair(d2), master.chainCode, master.network) |
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node.depth = master.depth |
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node.index = master.index |
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node.masterFingerprint = master.masterFingerprint |
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return node |
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} |
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var seed = crypto.randomBytes(32) |
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var master = bitcoin.HDNode.fromSeedBuffer(seed) |
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var child = master.derive(6) // m/6
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// now for the recovery
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var neuteredMaster = master.neutered() |
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var recovered = recoverParent(neuteredMaster, child) |
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assert.strictEqual(recovered.toBase58(), master.toBase58()) |
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}) |
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}) |
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