This ITL Bulletin gives a status report on the development of the AES, summarizes the evaluation process, and briefly describes the five finalist algorithms selected in Round 1 of the AES development process. These algorithms had been submitted by members of the cryptographic community from around the world. At that conference and in a published Federal Register notice, NIST solicited public comments on the candidates. The public comment period on the initial review of the algorithms closed on April 15, 1999. In the call for candidate algorithms, NIST specified the evaluation criteria that would be used to compare the candidate algorithms.
Security is the most important factor in the evaluation.
Security encompasses features such as resistance of the algorithm to cryptanalysis, soundness of its mathematical basis, randomness of the algorithm output, and relative security as compared to other candidates. The speed of the algorithms on a variety of platforms must also be considered. During Round 1, the focus was primarily on the speed associated with 128-bit keys. Additionally, memory requirements and constraints for software implementations of the candidates are important considerations. The third area of evaluation is algorithm and implementation characteristics such as flexibility, hardware and software suitability, and algorithm simplicity.