From 2ccf00f4be27d41c37f1ca5181c61edbda454140 Mon Sep 17 00:00:00 2001
From: Daniel Cousens <github@dcousens.com>
Date: Tue, 18 Aug 2015 15:39:43 +1000
Subject: [PATCH] integration: clean up single-key stealth derivation
---
test/integration/crypto.js | 51 ++++++++++++++++++++++----------------
1 file changed, 29 insertions(+), 22 deletions(-)
diff --git a/test/integration/crypto.js b/test/integration/crypto.js
index 7c97cd0..9f3e0c8 100644
--- a/test/integration/crypto.js
+++ b/test/integration/crypto.js
@@ -9,35 +9,42 @@ var crypto = require('crypto')
describe('bitcoinjs-lib (crypto)', function () {
it('can generate a single-key stealth address', function () {
- var receiver = bitcoin.ECPair.fromWIF('5KYZdUEo39z3FPrtuX2QbbwGnNP5zTd7yyr2SC1j299sBCnWjss')
-
- // XXX: ephemeral, must be random (and secret to sender) to preserve privacy
- var sender = bitcoin.ECPair.fromWIF('Kxr9tQED9H44gCmp6HAdmemAzU3n84H3dGkuWTKvE23JgHMW8gct')
-
var G = bitcoin.ECPair.curve.G
- var d = receiver.d // secret (receiver only)
- var Q = receiver.Q // shared
+ var n = bitcoin.ECPair.curve.n
- var e = sender.d // secret (sender only)
- var P = sender.Q // shared
+ function stealthSend (Q, nonce) {
+ var noncePair = new bitcoin.ECPair(bigi.fromBuffer(nonce))
+ var e = noncePair.d
+ var eQ = Q.multiply(e)
+ var c = bigi.fromBuffer(bitcoin.crypto.sha256(eQ.getEncoded()))
+ var cG = G.multiply(c)
+ var Qprime = Q.add(cG)
- // derived shared secret
- var eQ = Q.multiply(e) // sender
- var dP = P.multiply(d) // receiver
- assert.deepEqual(eQ.getEncoded(), dP.getEncoded())
+ return {
+ address: new bitcoin.ECPair(null, Qprime).getAddress(),
+ nonceQ: noncePair.Q
+ }
+ }
- var c = bigi.fromBuffer(bitcoin.crypto.sha256(eQ.getEncoded()))
- var cG = G.multiply(c)
+ function stealthReceive (d, P) {
+ var dP = P.multiply(d)
+ var c = bigi.fromBuffer(bitcoin.crypto.sha256(dP.getEncoded()))
+ var derived = new bitcoin.ECPair(d.add(c).mod(n))
- // derived public key
- var QprimeS = Q.add(cG)
- var QprimeR = G.multiply(d.add(c))
- assert.deepEqual(QprimeR.getEncoded(), QprimeS.getEncoded())
+ return {
+ keyPair: derived
+ }
+ }
- // derived shared-secret address
- var address = new bitcoin.ECPair(null, QprimeS).getAddress()
+ // receiver private key
+ var receiver = bitcoin.ECPair.fromWIF('5KYZdUEo39z3FPrtuX2QbbwGnNP5zTd7yyr2SC1j299sBCnWjss')
+ var nonce = crypto.randomBytes(32)
- assert.strictEqual(address, '1EwCNJNZM5q58YPPTnjR1H5BvYRNeyZi47')
+ var stealthS = stealthSend(receiver.Q, nonce)
+ var stealthR = stealthReceive(receiver.d, stealthS.nonceQ)
+
+ // and check that we derived both sides correctly
+ assert.equal(stealthS.address, stealthR.keyPair.getAddress())
})
// TODO