Advanced Encryption Standard (AES), or Rijndael as it can also be referred to, is a block cipher that has been received as the standard for encryption by the United States government. Being a block cipher, this encryption method takes a group of bits that is of a fixed size, performs the actual encryption, and then has an output that is also the same size of bits as the input. This method uses a secret key of a varying size in conjunction with the plain text input data in order to create the encrypted data of the same size. The decryption method of the data works in the same way by taking the encrypted data along with the secret key to produce the original data. The fixed block size for the data that the AES method takes is 128 bits while the key can be 128, 192, or 256 bits. The 128 bits means that the block that the AES operates on is a 4x4 square of bytes.