Aes Process

The primary motivation for a new standard was the fact that DES has a relatively small 56-bit Key which was becoming vulnerable to Brute Force Attack s. In addition the DES was designed primarily for hardware and is relatively slow when implemented in software. While Triple-DES avoids the problem of a small Key Size , it is very slow in software, and also unsuitable for limited-resource platforms.

START OF THE PROCESS

On community was immediately intense, and NIST received a great many submissions during the three month comment period.

The result of this feedback was a call for new algorithms on of 128 Bit s and key sizes of 128, 192, and 256 bits. Such ciphers were rare at the time of the announcement; the best known was probably Square .

ROUNDS ONE AND TWO

In the nine months that followed, fifteen different designs were created and submitted from several different countries. They were, in alphabetical order:
: CAST-256 , CRYPTON , DEAL , DFC , E2 , FROG , HPC , LOKI97 , MAGENTA , MARS , RC6 , Rijndael , SAFER +, Serpent , and Twofish .

In the ensuing debate, many advantages and disadvantages of the different candidates were investigated by cryptographers; they were assessed not only on security, but also on performance in a variety of settings (PCs of various architectures, smart cards, hardware implementations) and on their feasibility in limited environments (smart cards with very limited memory, low gate count implementations, FPGAs).

Some designs fell due to Cryptanalysis that ranged from merely glancing blows to highly destructive assaults, while others lost favour due to poor performance in various environments or through having little to offer over other candidates. NIST held two conferences to discuss the submissions (AES1, August 1998 and AES2, March 1999 ), and in April 1999 they announced that they were narrowing the field from fifteen to five: MARS, RC6, Rijndael, Serpent, and Twofish. All five originated from cryptographers well known and respected in the community.

A further round of intense analysis and cryptanalysis followed, culminating in the AES3 conference in April 2000 , at which a representative of each of the final five teams made a presentation arguing why their standard should be chosen as the AES.

SELECTION OF THE WINNER

On October 2 , 2000 , NIST announced that Rijndael had been selected as the proposed AES, and underwent the process of being made the official standard. On November 26 , 2001 , NIST announced that AES was approved as FIPS PUB 197.

NIST won praises from the cryptographic community for the openness and care with which they ran the standards process. Bruce Schneier , one of the authors of the losing Twofish algorithm, wrote after the competition was over that "I have nothing but good things to say about NIST and the AES process" {Link without Title} .

REFERENCES

A historical overview of the process can be found on NIST 's website {Link without Title} .

On the Sci.crypt newsgroup, there are extensive discussions about the AES process:

First AES conference

Second AES conference

Information About

Aes Process