Today' s cryptographic algorithms are designed in a way that they combine m athem atical theory and practice o f computer science in order to improve resistance to cryptanalysis. Cryptographic algorithms are designed around the binary data form at keeping in mind the presumption o f hardening possibility o f cracking the algorithm. One o f the algorithms whose resistance to cryptanalysis during the past 16 years is extensively tested algorithm AES. The Advanced Encryption Standard (AES) is the first cryptographic standard aroused as the result o f public competition established by U.S. National Institute o f Standards and Technology (NIST). AES has emerged as restriction on winner o f this com petition, called Rijndael algorithm on the block size o f 128 bits. From the moment o f its acceptance o f the standard in