symmetric encryption convenience class

lib/expmt/encryption.js

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+var AES = require('./aes');
+var CBC = require('./cbc');
+var Random = require('../random');
+var Hash = require('../hash');
+
+var Encryption = function Encryption() {
+};
+
+Encryption.encrypt = function(messagebuf, passwordstr) {
+  var cipherkeybuf = Hash.sha256(new Buffer(passwordstr));
+  return Encryption.encryptCipherkey(messagebuf, cipherkeybuf);
+};
+
+Encryption.decrypt = function(encbuf, passwordstr) {
+  var cipherkeybuf = Hash.sha256(new Buffer(passwordstr));
+  return Encryption.decryptCipherkey(encbuf, cipherkeybuf);
+};
+
+Encryption.encryptCipherkey = function(messagebuf, cipherkeybuf, ivbuf) {
+  ivbuf = ivbuf || Random.getRandomBuffer(128 / 8);
+  var ctbuf = CBC.encrypt(messagebuf, ivbuf, AES, cipherkeybuf);
+  var encbuf = Buffer.concat([ivbuf, ctbuf]);
+  return encbuf;
+};
+
+Encryption.decryptCipherkey = function(encbuf, cipherkeybuf) {
+  var ivbuf = encbuf.slice(0, 128 / 8);
+  var ctbuf = encbuf.slice(128 / 8);
+  var messagebuf = CBC.decrypt(ctbuf, ivbuf, AES, cipherkeybuf);
+  return messagebuf;
+};
+
+module.exports = Encryption;

test/test.encryption.js

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+var should = require('chai').should();
+var Encryption = require('../lib/expmt/encryption');
+
+describe('Encryption', function() {
+
+  describe('@encrypt', function() {
+
+    it('should return encrypt one block', function() {
+      var password = "password";
+      var messagebuf = new Buffer(128 / 8 - 1);
+      messagebuf.fill(0);
+      var encbuf = Encryption.encrypt(messagebuf, password);
+      encbuf.length.should.equal(128 / 8 + 128 / 8);
+    });
+
+  });
+
+  describe('@decrypt', function() {
+
+    it('should decrypt that which was encrypted', function() {
+      var password = "password";
+      var messagebuf = new Buffer(128 / 8 - 1);
+      messagebuf.fill(0);
+      var encbuf = Encryption.encrypt(messagebuf, password);
+      var messagebuf2 = Encryption.decrypt(encbuf, password);
+      messagebuf2.toString('hex').should.equal(messagebuf.toString('hex'));
+    });
+
+  });
+
+  describe('@encryptCipherkey', function() {
+
+    it('should return encrypt one block', function() {
+      var cipherkeybuf = new Buffer(256 / 8);
+      cipherkeybuf.fill(0x10);
+      var ivbuf = new Buffer(128 / 8);
+      ivbuf.fill(0);
+      var messagebuf = new Buffer(128 / 8 - 1);
+      messagebuf.fill(0);
+      var encbuf = Encryption.encryptCipherkey(messagebuf, cipherkeybuf, ivbuf);
+      encbuf.length.should.equal(128 / 8 + 128 / 8);
+    });
+
+    it('should return encrypt two blocks', function() {
+      var cipherkeybuf = new Buffer(256 / 8);
+      cipherkeybuf.fill(0x10);
+      var ivbuf = new Buffer(128 / 8);
+      ivbuf.fill(0);
+      var messagebuf = new Buffer(128 / 8);
+      messagebuf.fill(0);
+      var encbuf = Encryption.encryptCipherkey(messagebuf, cipherkeybuf, ivbuf);
+      encbuf.length.should.equal(128 / 8 + 128 / 8 + 128 / 8);
+    });
+
+  });
+
+  describe('@decryptCipherkey', function() {
+    
+    it('should decrypt that which was encrypted', function() {
+      var cipherkeybuf = new Buffer(256 / 8);
+      cipherkeybuf.fill(0x10);
+      var ivbuf = new Buffer(128 / 8);
+      ivbuf.fill(0);
+      var messagebuf = new Buffer(128 / 8);
+      messagebuf.fill(0);
+      var encbuf = Encryption.encryptCipherkey(messagebuf, cipherkeybuf, ivbuf);
+      var messagebuf2 = Encryption.decryptCipherkey(encbuf, cipherkeybuf);
+      messagebuf2.toString('hex').should.equal(messagebuf.toString('hex'));
+    });
+
+  });
+
+});