AES is the Advanced Encryption Standard, a United States government standard

algorithm for encrypting and decrypting data. The standard is described in Federal

Information Processing Standard (FIPS) 197.1

On January 2, 1997, The National Institute of Standards and Technology (NIST)

published a request for comments for the “Development of a Federal Information

Processing Standard for Advanced Encryption Standard.”2 NIST sought to “consider

alternatives that offer a higher level of security”3 than that offered by the Data Encryption

Standard (DES), which grew vulnerable to brute-force attacks due to its 56-bit effective

key length.AES candidates were required to support a symmetric block cipher that

supported multiple key lengths. The algorithm had to be publicly defined, free to use, and

able to run efficiently in both hardware and software