AES

lib/expmt/aes.js

@@ -0,0 +1,47 @@
+var aes = require('aes');
+
+var AES = function AES() {
+};
+
+AES.encrypt = function(messagebuf, keybuf) {
+  var key = AES.buf2words(keybuf);
+  var message = AES.buf2words(messagebuf);
+  var a = new aes(key);
+  var enc = a.encrypt(message);
+  var encbuf = AES.words2buf(enc);
+  return encbuf;
+};
+
+AES.decrypt = function(encbuf, keybuf) {
+  var enc = AES.buf2words(encbuf);
+  var key = AES.buf2words(keybuf);
+  var a = new aes(key);
+  var message = a.decrypt(enc);
+  var messagebuf = AES.words2buf(message);
+  return messagebuf;
+};
+
+AES.buf2words = function(buf) {
+  if (buf.length % 4)
+    throw new Error('buf length must be a multiple of 4');
+
+  var words = [];
+
+  for (var i = 0; i < buf.length / 4; i++) {
+    words.push(buf.readUInt32BE(i * 4));
+  };
+
+  return words;
+};
+
+AES.words2buf = function(words) {
+  var buf = new Buffer(words.length * 4);
+
+  for (var i = 0; i < words.length; i++) {
+    buf.writeUInt32BE(words[i], i * 4);
+  };
+
+  return buf;
+};
+
+module.exports = AES;

package.json

@@ -16,6 +16,7 @@
     "multisig"
   ],
   "dependencies": {
+    "aes": "=0.1.0",
     "bn.js": "=0.13.3",
     "bs58": "=1.2.1",
     "elliptic": "=0.15.7",

test/test.aes.js

@@ -0,0 +1,85 @@
+var should = require('chai').should();
+var Hash = require('../lib/hash');
+var AES = require('../lib/expmt/aes');
+
+describe('AES', function() {
+  var m128 = Hash.sha256(new Buffer('test1')).slice(0, 128 / 8);
+  
+  var k128 = Hash.sha256(new Buffer('test2')).slice(0, 128 / 8);
+  var k192 = Hash.sha256(new Buffer('test2')).slice(0, 192 / 8);
+  var k256 = Hash.sha256(new Buffer('test2')).slice(0, 256 / 8);
+
+  var e128 = new Buffer('3477e13884125038f4dc24e9d2cfbbc7', 'hex');
+  var e192 = new Buffer('b670954c0e2da1aaa5f9063de04eb961', 'hex');
+  var e256 = new Buffer('dd2ce24581183a4a7c0b1068f8bc79f0', 'hex');
+
+
+  describe('@encrypt', function() {
+    
+    it('should encrypt with a 128 bit key', function() {
+      var encbuf = AES.encrypt(m128, k128);
+      encbuf.toString('hex').should.equal(e128.toString('hex'));
+    });
+      
+    it('should encrypt with a 192 bit key', function() {
+      var encbuf = AES.encrypt(m128, k192);
+      encbuf.toString('hex').should.equal(e192.toString('hex'));
+    });
+      
+    it('should encrypt with a 256 bit key', function() {
+      var encbuf = AES.encrypt(m128, k256);
+      encbuf.toString('hex').should.equal(e256.toString('hex'));
+    });
+      
+  });
+
+  describe('@decrypt', function() {
+    
+    it('should encrypt/decrypt with a 128 bit key', function() {
+      var encbuf = AES.encrypt(m128, k128);
+      var m = AES.decrypt(encbuf, k128);
+      m.toString('hex').should.equal(m128.toString('hex'));
+    });
+      
+    it('should encrypt/decrypt with a 192 bit key', function() {
+      var encbuf = AES.encrypt(m128, k192);
+      var m = AES.decrypt(encbuf, k192);
+      m.toString('hex').should.equal(m128.toString('hex'));
+    });
+      
+    it('should encrypt/decrypt with a 256 bit key', function() {
+      var encbuf = AES.encrypt(m128, k256);
+      var m = AES.decrypt(encbuf, k256);
+      m.toString('hex').should.equal(m128.toString('hex'));
+    });
+      
+  });
+
+  describe('@buf2words', function() {
+    
+    it('should convert this 4 length buffer into an array', function() {
+      var buf = new Buffer([0, 0, 0, 0]);
+      var words = AES.buf2words(buf);
+      words.length.should.equal(1);
+    });
+
+    it('should throw an error on this 5 length buffer', function() {
+      var buf = new Buffer([0, 0, 0, 0, 0]);
+      (function() {
+        var words = AES.buf2words(buf);
+      }).should.throw();
+    });
+
+  });
+
+  describe('@words2buf', function() {
+    
+    it('should convert this array into a buffer', function() {
+      var a = [100, 0];
+      var buf = AES.words2buf(a);
+      buf.length.should.equal(8);
+    });
+
+  });
+
+});