An encryption methodology developed by the United States National Institute of Standards and Technology (NIST) and publicized as a Federal Information Processing Standard (FIPS). AES is a privacy transformation for Internet Protocol Security (IPSec) and Internet Key Exchange (IKE). AES was designed not only to replace the Data Encryption Standard (DES) but also to be more secure than its predecessor. Compared to DES, AES offers a large key size and ensures that the only known approach to decrypt messages is for cyber-intruders to try every possible key—a daunting task indeed. The AES has variable key lengths, with algorithms specifying a 128-bit key (the default), a 192-bit key, and a 256-bit key. Although AES was developed to replace DES, NIST suggests that DES will remain an approved encryption algorithm for the near future. Cisco Systems, Inc. Advanced Encryption Standard (AES). [Online, March 2, 2004.] Cisco Systems, Inc. Website. http://www.cisco.com/univercd/cc/td/doc/ product/software/ios122/122newft/122t/122t13/.