From 893423aa93f24f472c41ae84da8d4dbe2cee1966 Mon Sep 17 00:00:00 2001
From: Friedel Ziegelmayer <dignifiedquire@gmail.com>
Date: Fri, 20 May 2016 15:55:19 +0200
Subject: [PATCH] go interop for keyStretcher

---
 README.md                       | 23 +++++++++++++++++++++++
 src/key-stretcher.js            | 19 ++++++++-----------
 test/fixtures/go-stretch-key.js | 31 +++++++++++++++++++++++++++++++
 test/key-stretcher.spec.js      | 21 +++++++++++++++++++++
 4 files changed, 83 insertions(+), 11 deletions(-)
 create mode 100644 test/fixtures/go-stretch-key.js

diff --git a/README.md b/README.md
index 78304aa..c250003 100644
--- a/README.md
+++ b/README.md
@@ -42,6 +42,29 @@ Returns an object of the form
 }
 ```
 
+### `keyStretcher(cipherType, hashType, secret)`
+
+- `cipherType: String`, one of `'AES-128'`, `'AES-256'`, `'Blowfish'`
+- `hashType: String`, one of `'SHA1'`, `SHA256`, `SHA512`
+- `secret: Buffer`
+
+Generates a set of keys for each party by stretching the shared key.
+
+Returns an object of the form
+```js
+{
+  k1: {
+    iv: Buffer,
+    cipherKey: Buffer,
+    macKey: Buffer
+  },
+  k2: {
+    iv: Buffer,
+    cipherKey: Buffer,
+    macKey: Buffer
+  }
+}
+```
 ### `marshalPublicKey(key[, type])`
 
 - `key: crypto.rsa.RsaPublicKey`
diff --git a/src/key-stretcher.js b/src/key-stretcher.js
index bb5be13..7aa918b 100644
--- a/src/key-stretcher.js
+++ b/src/key-stretcher.js
@@ -81,17 +81,14 @@ module.exports = (cipherType, hashType, secret) => {
   const r1 = createBuffer(result.getBytes(half))
   const r2 = createBuffer(result.getBytes())
 
-  const k1 = {
-    IV: r1.getBytes(ivSize),
-    CipherKey: r1.getBytes(cipherKeySize),
-    MacKey: r1.getBytes()
-  }
+  const createKey = (res) => ({
+    iv: new Buffer(res.getBytes(ivSize), 'binary'),
+    cipherKey: new Buffer(res.getBytes(cipherKeySize), 'binary'),
+    macKey: new Buffer(res.getBytes(), 'binary')
+  })
 
-  const k2 = {
-    IV: r2.getBytes(ivSize),
-    CipherKey: r2.getBytes(cipherKeySize),
-    MacKey: r2.getBytes()
+  return {
+    k1: createKey(r1),
+    k2: createKey(r2)
   }
-
-  return {k1, k2}
 }
diff --git a/test/fixtures/go-stretch-key.js b/test/fixtures/go-stretch-key.js
new file mode 100644
index 0000000..597ffcb
--- /dev/null
+++ b/test/fixtures/go-stretch-key.js
@@ -0,0 +1,31 @@
+'use strict'
+
+module.exports = [{
+  cipher: 'AES-256',
+  hash: 'SHA256',
+  secret: new Buffer([
+    195, 191, 209, 165, 209, 201, 127, 122, 136, 111, 31, 66, 111, 68, 38, 155, 216, 204, 46, 181, 200, 188, 170, 204, 104, 74, 239, 251, 173, 114, 222, 234
+  ]),
+  k1: {
+    iv: new Buffer([
+      208, 132, 203, 169, 253, 52, 40, 83, 161, 91, 17, 71, 33, 136, 67, 96
+    ]),
+    cipherKey: new Buffer([
+      156, 48, 241, 157, 92, 248, 153, 186, 114, 127, 195, 114, 106, 104, 215, 133, 35, 11, 131, 137, 123, 70, 74, 26, 15, 60, 189, 32, 67, 221, 115, 137
+    ]),
+    macKey: new Buffer([
+      6, 179, 91, 245, 224, 56, 153, 120, 77, 140, 29, 5, 15, 213, 187, 65, 137, 230, 202, 120
+    ])
+  },
+  k2: {
+    iv: new Buffer([
+      236, 17, 34, 141, 90, 106, 197, 56, 197, 184, 157, 135, 91, 88, 112, 19
+    ]),
+    cipherKey: new Buffer([
+      151, 145, 195, 219, 76, 195, 102, 109, 187, 231, 100, 150, 132, 245, 251, 130, 254, 37, 178, 55, 227, 34, 114, 39, 238, 34, 2, 193, 107, 130, 32, 87
+    ]),
+    macKey: new Buffer([
+      3, 229, 77, 212, 241, 217, 23, 113, 220, 126, 38, 255, 18, 117, 108, 205, 198, 89, 1, 236
+    ])
+  }
+}]
diff --git a/test/key-stretcher.spec.js b/test/key-stretcher.spec.js
index 7e6b7a2..2861bba 100644
--- a/test/key-stretcher.spec.js
+++ b/test/key-stretcher.spec.js
@@ -4,11 +4,13 @@
 const expect = require('chai').expect
 
 const crypto = require('../src')
+const fixtures = require('./fixtures/go-stretch-key')
 
 describe('keyStretcher', () => {
   describe('generate', () => {
     const ciphers = ['AES-128', 'AES-256', 'Blowfish']
     const hashes = ['SHA1', 'SHA256']
+    // add 'SHA512' when https://github.com/digitalbazaar/forge/issues/401 is resolved
     const res = crypto.generateEphemeralKeyPair('P-256')
     const secret = res.genSharedKey(res.key)
 
@@ -22,4 +24,23 @@ describe('keyStretcher', () => {
       })
     })
   })
+
+  describe('go interop', () => {
+    fixtures.forEach((test) => {
+      it(`${test.cipher} - ${test.hash}`, () => {
+        const cipher = test.cipher
+        const hash = test.hash
+        const secret = test.secret
+        const keys = crypto.keyStretcher(cipher, hash, secret)
+
+        expect(keys.k1.iv).to.be.eql(test.k1.iv)
+        expect(keys.k1.cipherKey).to.be.eql(test.k1.cipherKey)
+        expect(keys.k1.macKey).to.be.eql(test.k1.macKey)
+
+        expect(keys.k2.iv).to.be.eql(test.k2.iv)
+        expect(keys.k2.cipherKey).to.be.eql(test.k2.cipherKey)
+        expect(keys.k2.macKey).to.be.eql(test.k2.macKey)
+      })
+    })
+  })
 })