Paper 2019/530

Speed-up of SCA attacks on 32-bit multiplications

Robert Nguyen and Adrien Facon and Sylvain Guilley and Guillaume Gautier and Safwan El Assad

Abstract

Many crypto-algorithms, Deep-Learning, DSP compute on words larger than 8-bit. SCA attacks can easily be done on Boolean operations like XOR, AND, OR, and substitution operations like s-box, p-box or q-box, as 8-bit hypothesis or less are enough to forge attacks. However, attacking larger hypothesis word increases exponentially required resources: memory and computation power. Considering multiplication, 32-bit operation implies $2^{32}$ hypothesis. Then a direct SCA attack cannot be efficiently performed. We propose to perform instead 4 small 8-bit SCA attacks. 32-bit attack complexity is reduced to 8-bit only complexity.

Note: It is precised how the divide-and-conquer is performed