Practical template attacks based on pooled covariance matrix

Abstract

In order to improve the efficiency of the template attack, people often pay attention to the points of interest, but neglect the number of training sets. In fact, the appropriate training set size is the key to ensure the template attack. The formula of the number of training set needed for the success template attack is deduced by probability analyzing. Further, in the case of the limited number of training set, a practical method based on pooled covariance matrix is proposed. Experimental results from attacking 10000 AES encryption traces showed that the proposed method can not only avoid the numerical problems, but also improve the success rate significantly compared to the traditional template attacks.