RSA Laboratories

3.3.1 What is the AES?

RSA Labs' FAQ 4.1

(Revised January 2003)

The AES is the Advanced Encryption Standard. The AES was issued as FIPS PUB 197 by NIST (see Question 6.2.1) standard is the successor to DES (see Question 3.2.1). In January 1997 the AES initiative was announced and in September 1997 the public was invited to propose suitable block ciphers as candidates for the AES. The AES algorithm was selected in October 2001 and the standard was published in November 2002. NIST's intent was to have a cipher that will remain secure well into the next century.

AES supports key sizes of 128 bits, 192 bits, and 256 bits, in contrast to the 56-bit keys offered by DES.

The AES algorithm resulted from a multi-year evaluation process led by NIST with submissions and review by an international community of cryptography experts. The Rijndael algorithm, invented by Joan Daemen and Vincent Rijmen, was selected as the standard.

Over time, many implementations are expected to upgrade to AES, both because it offers a 128-bit key size, and because it is a federal standard.

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