From 8743c68ce67a9e5f21e0f3f6ed2e023c697d633d Mon Sep 17 00:00:00 2001
From: "Ryan X. Charles" <ryan@bitpay.com>
Date: Wed, 13 Aug 2014 17:31:28 -0400
Subject: [PATCH] kdf

---
 index.js         | 35 +++++++++++++++++++++--------------
 lib/kdf.js       | 33 +++++++++++++++++++++++++++++++++
 test/test.kdf.js | 39 +++++++++++++++++++++++++++++++++++++++
 3 files changed, 93 insertions(+), 14 deletions(-)
 create mode 100644 lib/kdf.js
 create mode 100644 test/test.kdf.js

diff --git a/index.js b/index.js
index a8f495e..e7bf374 100644
--- a/index.js
+++ b/index.js
@@ -1,20 +1,27 @@
 var privsec = module.exports;
 
-privsec.address = require('./lib/address');
-privsec.base58 = require('./lib/base58');
-privsec.base58check = require('./lib/base58check');
-privsec.bip32 = require('./lib/bip32');
-privsec.bn = require('./lib/bn');
-privsec.constants = require('./lib/constants');
-privsec.ecdsa = require('./lib/ecdsa');
-privsec.hash = require('./lib/hash');
-privsec.key = require('./lib/key');
-privsec.point = require('./lib/point');
-privsec.privkey = require('./lib/privkey');
-privsec.pubkey = require('./lib/pubkey');
-privsec.random = require('./lib/random');
-privsec.signature = require('./lib/signature');
+//main bitcoin library
+privsec.Address = require('./lib/address');
+privsec.Base58 = require('./lib/base58');
+privsec.Base58Check = require('./lib/base58check');
+privsec.BIP32 = require('./lib/bip32');
+privsec.BN = require('./lib/bn');
+privsec.Constants = require('./lib/constants');
+privsec.ECDSA = require('./lib/ecdsa');
+privsec.Hash = require('./lib/hash');
+privsec.KDF = require('./lib/kdf');
+privsec.Key = require('./lib/key');
+privsec.Point = require('./lib/point');
+privsec.Privkey = require('./lib/privkey');
+privsec.Pubkey = require('./lib/pubkey');
+privsec.Random = require('./lib/random');
+privsec.Signature = require('./lib/signature');
 
+//experimental
+//privsec.expmt = {};
+//privsec.expmt.Stealth = require('./lib/expmt/stealth');
+
+//dependencies
 privsec.deps = {};
 privsec.deps.bnjs = require('bn.js');
 privsec.deps.bs58 = require('bs58');
diff --git a/lib/kdf.js b/lib/kdf.js
new file mode 100644
index 0000000..91d0752
--- /dev/null
+++ b/lib/kdf.js
@@ -0,0 +1,33 @@
+var Bn = require('./bn');
+var Privkey = require('./privkey');
+var Point = require('./point');
+var Pubkey = require('./pubkey');
+var Key = require('./key');
+var Hash = require('./hash');
+
+function KDF() {
+};
+
+KDF.buf2key = function(buf) {
+  return KDF.sha256hmac2key(buf);
+};
+
+KDF.sha256hmac2key = function(buf) {
+  var privkey = KDF.sha256hmac2privkey(buf);
+  var key = new Key(privkey);
+  key.privkey2pubkey();
+  return key;
+};
+
+KDF.sha256hmac2privkey = function(buf) {
+  var bn;
+  var concat = new Buffer([]);
+  do {
+    var hash = Hash.sha256hmac(buf, concat);
+    var bn = Bn.fromBuffer(hash);
+    concat = Buffer.concat([concat, new Buffer(0)]);
+  } while(!bn.lt(Point.getN()));
+  return new Privkey(bn);
+};
+
+module.exports = KDF;
diff --git a/test/test.kdf.js b/test/test.kdf.js
new file mode 100644
index 0000000..4571b4c
--- /dev/null
+++ b/test/test.kdf.js
@@ -0,0 +1,39 @@
+var should = require('chai').should();
+var KDF = require('../lib/kdf');
+var Hash = require('../lib/hash');
+
+describe('kdf', function() {
+  
+  describe('#buf2key', function() {
+
+    it('should compute these known values', function() {
+      var buf = Hash.sha256(new Buffer('test'));
+      var key = KDF.buf2key(buf);
+      key.privkey.toString().should.equal('KxxVszVMFLGzmxpxR7sMSaWDmqMKLVhKebX5vZbGHyuR8spreQ7V');
+      key.pubkey.toString().should.equal('03774f761ae89a0d2fda0d532bad62286ae8fcda9bc38c060036296085592a97c1');
+    });
+
+  });
+
+  describe('#sha256hmac2key', function() {
+
+    it('should compute these known values', function() {
+      var buf = Hash.sha256(new Buffer('test'));
+      var key = KDF.sha256hmac2key(buf);
+      key.privkey.toString().should.equal('KxxVszVMFLGzmxpxR7sMSaWDmqMKLVhKebX5vZbGHyuR8spreQ7V');
+      key.pubkey.toString().should.equal('03774f761ae89a0d2fda0d532bad62286ae8fcda9bc38c060036296085592a97c1');
+    });
+
+  });
+
+  describe('#sha256hmac2privkey', function() {
+
+    it('should compute this known privkey', function() {
+      var buf = Hash.sha256(new Buffer('test'));
+      var privkey = KDF.sha256hmac2privkey(buf);
+      privkey.toString().should.equal('KxxVszVMFLGzmxpxR7sMSaWDmqMKLVhKebX5vZbGHyuR8spreQ7V');
+    });
+
+  });
+
+});