Paper 2004/149

Secure and Efficient AES Software Implementation for Smart Caards

E. Trichina and L. Korkishko

Abstract

In implementing cryptographic algorithms on limited devices such as smart cards, speed and memory requirements had always presented a challenge. With the advent of side channel attacks, this task became even more difficult because a programmer must take into account countermeasures against such attacks, which often increases computational time, or memory requirements, or both. In this paper we describe a new method for secure implementation of the Advanced Encryption Standard algorithm. The method is based on a data masking technique, which is the most widely used countermeasure against power analysis and timing attacks at a software level. The change of element representation allows us to replace all multiplications in the field with table lookups using masked log/alog tables, and achieve an efficient solution that combines low memory requirements with high speed and resistance to attacks.