I. Introduction
AES also coined as the Rijndael method which is termed after the two scientists Vincent Rijmen and Joan Daemen, was taken into consideration after the DES (Data Encryption Standard) algorithm had broken in 1998 by a system that took about $250,000 for its construction. Talking about other reasons behind adopting AES, was the block size of triple DES (64 bit) and inefficiency of DES when it comes to practice and real life security measures [1]–[2]. Finally, keeping aside all the other problems, NIST (full form) had selected an algorithm known as Rijndael and on 26 November 2001, AES became a FIPS (Federal Information Processing Standard). Thereafter AES has turned out to be the most popular and widely adopted symmetric encryption algorithm for which no practical cryptanalytic attacks have been discovered. AES is a symmetric block cipher that implies the usage of a single key for encoding/decoding. According to the algorithm, it can take block size of 128 bits which has options of three different keys, which are 128, 192 and 256 bits respectively [3]–[6]. AES is not a traditional Feistel structure and most of the AES parameters are based on selected key as denoted in table 1 below. Showing rounds with respect to key size in aes
S.N. | Algorithm | Key | Number of executed rounds |
---|---|---|---|
1 | AES (128) | 128 bits | 10 |
2 | AES (192) | 192 bits | 12 |
3 | AES (256) | 256 bits | 14 |