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Request for Comments on the Finalist (Round 2) Candidate Algorithms for the Advanced Encryption Standard (AES)
September 15, 1999

A process to develop a Federal Information Processing Standard (FIPS) for an Advanced Encryption Standard (AES) specifying an Advanced Encryption Algorithm (AEA) has been initiated by the National Institute of Standards and Technology (NIST). In the Fall of 1998, NIST announced fifteen publicly submitted algorithms as candidates for the AES, and invites public review, comment, and analysis in order to narrow the field of candidates to (approximately) five or fewer finalists. During the Round 1 technical evaluation period, these fifteen candidates were subjected to extensive analysis and testing by the cryptographic community. 

At the conclusion of Round 1, NIST took the following information into consideration: (1) The submitted (official) versions of the AES candidate algorithms, (2) Round 1 public comments, (3) papers and discussions at the Second AES Candidate Conference, (4) results of NIST efficiency and statistical analysis, and (5) other relevant data (e.g., presentations at the Sixth Fast Software Encryption Workshop, discussions on NIST’s AES Electronic Discussion Forum, etc.). Using this information, NIST has selected the AES finalist candidate algorithms (‘‘finalists’’), which will be subjected to further analysis during Round 2 of the AES development effort. A list of the finalists, along with specifications and intellectual property information, is available at the AES home page,

This notice announces the beginning of the Round 2 technical evaluation period for the AES finalists. Additionally, the notice solicits comments on the finalists from the general public, academic and research communities, manufacturers, voluntary standards organizations, and Federal, state, and local government organizations. NIST will use these comments to select one or more of the finalists for inclusion in a draft Federal Information Processing Standards Publication (FIPS PUB), on which public comments will be invited via a future Federal Register announcement. NIST’s goal is that the AES will specify one or more unclassified, publicly disclosed encryption algorithm(s) available royalty-free worldwide that is (are) capable of protecting sensitive government information well into the next century.

Public comments for Round 2 are due May 15, 2000.

Federal Register Notice

Document Number: 99-24014
Created January 23, 2017, Updated June 22, 2020