Work with strings

Found by Tommy Valand

function StringEncrypter( encryptionScheme:String, encryptionKey:String ){
  try{
    encryptionScheme = encryptionScheme || this.DESEDE_ENCRYPTION_SCHEME;
    encryptionKey = encryptionKey || this.DEFAULT_ENCRYPTION_KEY;
    if( encryptionKey.length < 24 ){ 
      throw new java.lang.Exception( 
        'Encryption key was less than 24 characters.' ); 
    }
    var keyAsBytes = encryptionKey.getBytes( this.UNICODE_FORMAT );
    
    switch( encryptionScheme ){
      case this.DESEDE_ENCRYPTION_SCHEME: 
        this.keySpec = new javax.crypto.spec.DESedeKeySpec( keyAsBytes ); break;
      case this.DES_ENCRYPTION_SCHEME: 
        this.keySpec = new javax.crypto.spec.DESKeySpec( keyAsBytes ); break;
      default: 
        throw new java.lang.Exception( 
          "Encryption scheme not supported: "  + encryptionScheme );
    }

    this.keyFactory = javax.crypto.SecretKeyFactory.getInstance( encryptionScheme );
    this.cipher = javax.crypto.Cipher.getInstance( encryptionScheme );
  } catch( e ){ /* your exception handling */ }
}

StringEncrypter.prototype = {
  DESEDE_ENCRYPTION_SCHEME: "DESede",
  DES_ENCRYPTION_SCHEME: "DES",
  DEFAULT_ENCRYPTION_KEY: 
    "The ships hung in the sky in much the same way that bricks don't.",
  UNICODE_FORMAT: "UTF8",
  
  keySpec: null,
  keyFactory: null,
  cipher: null,
  
  encrypt: function( unencryptedString ){
    if( !unencryptedString ){ return ''; }
    
    try {
      var key = this.keyFactory.generateSecret( this.keySpec );
      this.cipher.init( javax.crypto.Cipher.ENCRYPT_MODE, key );
      var clearText = unencryptedString.getBytes( this.UNICODE_FORMAT );
      var cipherText = this.cipher.doFinal( clearText );

      var base64encoder = new sun.misc.BASE64Encoder();
      return base64encoder.encode( cipherText );
    } catch( e ){ /* your exception handling */ }
  },
  decrypt: function( encryptedString ){
    if( !encryptedString ){ return ''; }
    
    try {
      var key = this.keyFactory.generateSecret( this.keySpec );
      this.cipher.init( javax.crypto.Cipher.DECRYPT_MODE, key );
      var base64decoder = new sun.misc.BASE64Decoder();
      var clearText = base64decoder.decodeBuffer( encryptedString );
      var cipherText = this.cipher.doFinal( clearText );

      return new java.lang.String( cipherText );
    } catch( e ){ /* your exception handling */ }
  }
}

var encrypter = new StringEncrypter();
encrypter.encrypt( unencryptedString );

var encrypter = new StringEncrypter();
encrypter.decrypt( encryptedString );

See Tommy's blog for details