An Advanced Encryption Standard instruction set is now integrated into many processors. The purpose of the instruction set is to improve the speed and security of applications performing encryption and decryption using Advanced Encryption Standard (AES). They are often implemented as instructions implementing a single round of AES along with a special version for the last round which has a slightly different method. The side channel attack surface of AES is reduced when implemented in an instruction set, compared to when AES is implemented in software only.