simple AES encryption class for node - you can pass key and iv or it will create them - you can change them after object creation as well

AESnode.js

var AES=function(key,iv){ 
  this.rc=function(l){ l=l||16;
      var text = "", possible = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789";
      for(var i=0;i<l;i++) text += possible.charAt(Math.floor(Math.random() * possible.length));
      return text;
  }
  this.iv =iv ||this.rc();
  this.key=key||this.rc(128);
  this.decrypt = function(encryptdata) {
      var decipher = crypto.createDecipheriv('aes-256-cbc', crypto.createHash('sha256').update(this.key).digest(), this.iv);
      return decipher.update(new Buffer(encryptdata, 'base64').toString('binary'), 'binary', 'utf8')+decipher.final('utf8');
  }     
   this.encrypt = function(cleardata) {
      var encipher = crypto.createCipheriv('aes-256-cbc', crypto.createHash('sha256').update(this.key).digest(), this.iv);
      return new Buffer(encipher.update(cleardata, 'utf8', 'binary')+encipher.final('binary'), 'binary').toString('base64');
  }
};

AEStest.js

// test en- and decryption functionality

var AES=new AES();

console.log(AES.encrypt('whole lof of test data'));
console.log(AES.decrypt(AES.encrypt('whole lof of test data')));


// encrypt with fixed key, save IV and data

var AES2=new AES();

AES2.key='my saved key';
var saveText = AES2.iv + AES.encrypt('whole lotta data');
console.log(saveText);


// get IV and data, restore

var AES3= new AES();
AES3.key='my saved key';
AES3.iv =saveText.slice(0,16);
var cleartext= AES.decrypt( saveText.slice(16) );
console.log(cleartext);