The XTS working mode is a typical block cipher mode of operation using block cipher algorithm. The acronym of XTS stands for XEX Tweakable Block Ciphertext Stealing. According to this “ciphertext stealing” method, XTS can encrypt or decrypt sequences of arbitrary length of data block. i.e., data string that is 256 bits or 257 bits. Therefore, in XTS mode, the input or output data may also consist of a number of blocks in 128 bits followed by a separated partial block which is not empty and less than 128 bits. By IEEE Std 1619-2007, two cipherkeys in 256 bits are required in XTS mode. They are called tweakable key and encryption key, respectively.