A Parallel Yet Pipelined Architecture for Efficient Implementation of the Advanced Encryption Standard Algorithm on Reconfigurable Hardware

The Advanced Encryption System (AES) is used in almost all network-based applications to ensure security. The core computation of AES, which is performed on data blocks of 128 bits, is iterated for several rounds, depending on the key size. The strength of AES is proportional to the number of rounds applied. So far, the number of rounds is fixed to 10, 12 and 14 for a key size of 128, 192 and 256 bits respectively. Most cryptographers feel that the margin between the number of rounds specified in the cipher and the best known attacks is too small. On the other hand, it is clear that the overall efficiency of a given AES implementation is inversely proportional to the number of rounds imposed. In this paper, we propose a very efficient pipelined hardware implementation of AES-128. Besides, we show that if the required number of rounds must increase to defeat attackers, the proposed implementation stays efficient.