fix(aes): replace subtle.crypto with browserify-aes

Due to the design of `AES-CTR` in the webcrypto spec, there
is no streaming mode provided. This results in the counter
not being reused between subsequent calls to `encrypt` or
`decrypt`. As both the node.js and the go implementation rely
on this webcrypto had to be replaced.

package.json

@@ -7,7 +7,7 @@
     "node-webcrypto-ossl": false,
     "./src/crypto/webcrypto.js": "./src/crypto/webcrypto-browser.js",
     "./src/crypto/hmac.js": "./src/crypto/hmac-browser.js",
-    "./src/crypto/aes.js": "./src/crypto/aes-browser.js"
+    "./src/crypto/ciphers.js": "./src/crypto/ciphers-browser.js"
   },
   "scripts": {
     "lint": "aegir-lint",
@@ -32,6 +32,7 @@
   "dependencies": {
     "asn1.js": "^4.8.1",
     "async": "^2.1.2",
+    "browserify-aes": "^1.0.6",
     "multihashing-async": "^0.2.0",
     "node-webcrypto-ossl": "^1.0.7",
     "nodeify": "^1.0.0",
@@ -66,4 +67,4 @@
     "greenkeeperio-bot <support@greenkeeper.io>",
     "nikuda <nikuda@gmail.com>"
   ]
-}
+}

src/crypto/aes-browser.js

@@ -1,52 +0,0 @@
-'use strict'
-
-const nodeify = require('nodeify')
-
-const crypto = require('./webcrypto')()
-
-exports.create = function (key, iv, callback) {
-  nodeify(crypto.subtle.importKey(
-    'raw',
-    key,
-    {
-      name: 'AES-CTR'
-    },
-    false,
-    ['encrypt', 'decrypt']
-  ).then((key) => {
-    const counter = copy(iv)
-
-    return {
-      encrypt (data, cb) {
-        nodeify(crypto.subtle.encrypt(
-          {
-            name: 'AES-CTR',
-            counter: counter,
-            length: 128
-          },
-          key,
-          data
-        ).then((raw) => Buffer.from(raw)), cb)
-      },
-
-      decrypt (data, cb) {
-        nodeify(crypto.subtle.decrypt(
-          {
-            name: 'AES-CTR',
-            counter: counter,
-            length: 128
-          },
-          key,
-          data
-        ).then((raw) => Buffer.from(raw)), cb)
-      }
-    }
-  }), callback)
-}
-
-function copy (buf) {
-  const fresh = new Buffer(buf.length)
-  buf.copy(fresh)
-
-  return fresh
-}

src/crypto/aes.js

@@ -1,20 +1,20 @@
 'use strict'
 
-const crypto = require('crypto')
+const ciphers = require('./ciphers')
 
-const ciphers = {
+const CIPHER_MODES = {
   16: 'aes-128-ctr',
   32: 'aes-256-ctr'
 }
 
 exports.create = function (key, iv, callback) {
-  const name = ciphers[key.length]
-  if (!name) {
+  const mode = CIPHER_MODES[key.length]
+  if (!mode) {
     return callback(new Error('Invalid key length'))
   }
 
-  const cipher = crypto.createCipheriv(name, key, iv)
-  const decipher = crypto.createDecipheriv(name, key, iv)
+  const cipher = ciphers.createCipheriv(mode, key, iv)
+  const decipher = ciphers.createDecipheriv(mode, key, iv)
 
   const res = {
     encrypt (data, cb) {

src/crypto/ciphers-browser.js

@@ -0,0 +1,8 @@
+'use strict'
+
+const crypto = require('browserify-aes')
+
+module.exports = {
+  createCipheriv: crypto.createCipheriv,
+  createDecipheriv: crypto.createDecipheriv
+}

src/crypto/ciphers.js

@@ -0,0 +1,8 @@
+'use strict'
+
+const crypto = require('crypto')
+
+module.exports = {
+  createCipheriv: crypto.createCipheriv,
+  createDecipheriv: crypto.createDecipheriv
+}

test/aes.spec.js

@@ -14,7 +14,7 @@ const bytes = {
   32: 'AES-256'
 }
 
-describe.only('AES-CTR', () => {
+describe('AES-CTR', () => {
   Object.keys(bytes).forEach((byte) => {
     it(`${bytes[byte]} - encrypt and decrypt`, (done) => {
       const key = new Buffer(parseInt(byte, 10))