Performance Analysis of AES candidates on the 6805 CPU core
Geoffrey Keating · 1999
The AES candidate block ciphers Crypton, Mars, RC6, Rijndael, and Serpent were implemented on the Motorola 6805 series 8-bit architecture. Their performance, including ROM and RAM sizes and time to encrypt a single block, was measured in simulation, and the results presented and compared with results for the other NIST cryptography algorithms SHA and DEA and previously published results for AES candidate Twofish. Rijndael was found to be the clear “winner”, but the ciphers Crypton, Serpent, and Twofish also performed acceptably. The NIST is currently evaluating block cipher algorithms as part of its Advanced Encryption Standard development effort. Among the requirements for the AES is that it should be efficient on small 8-bit processors as found in smart cards. Unfortunately, although most of the AES submissions presented performance estimates (sometimes even timings of actual implementations) for some kind of 8-bit processor, there were almost as many 8-bit processors used as there were submissions. In this paper, we hope to rectify this by implementing the most likely AES candidates for a single 8-bit platform, the Motorola 6805 series [3] and measuring their performance in simulation. The candidates chosen were Crypton, Mars, RC6, Rijndael, and Serpent. The authors of the Twofish AES submission [8] have already implemented Twofish on a 6805 CPU, so we simply quote their results below. These include the fastest five algorithms on the reference platform. There is some discussion below of the next two fastest candidates, CAST and E2. 1 The 6805 processors The processor family we chose is based around the Motorola HC05 core. There are a large number of variants, all of which use the same instruction set and tim-