Paper 2010/056

Improved Cache Trace Attack on AES and CLEFIA by Considering Cache Miss and S-box Misalignment

Xin-jie ZHAO and Tao WANG

Abstract

This paper presents an improved Cache trace attack on AES and CLEFIA by considering Cache miss trace information and S-box misalignment. In 2006, O. Acıiçmez et al. present a trace driven Cache attack on AES first two rounds, and point out that if the Cache element number of the Cache block is 16, at most 48-bit of AES key can be obtained in the first round attack. Their attack is based on the ideal case when S-box elements are perfected aligned in the Cache block. However, this paper discovers that, the S-box elements are usually misaligned, and due to this feature and by considering Cache miss trace information, about 200 samples are enough to obtain full 128-bit AES key within seconds. In 2010, Chester Rebeiro et al. present the first trace driven Cache attack on C LEFIA by considering Cache hit information and obtain 128-bit key with 243 CLEFIA encryptions. In this paper, we present a new attack on CLEFIA by considering Cache miss information and S-box misalignment features, finally successfully obtain CLEFIA-128 key for about 220 samples within seconds.