Subset of the Rijndael [[block cipher]] Developed by 2 Belgian cryptographers Vincent Rijmen and Joan Daemen A family of ciphers with different key and block sizes NIST selected a block size of 128 bits with 3 different key lengths of 128,192 and 256 bits. Supersedes the [[Data Encryption Standard (3DES)]] A symmetric algorithm that uses the same key for encrypting and de-crypting data