Paper 2019/346

Yet Another Side Channel Cryptanalysis on SM3 Hash Algorithm

Christophe Clavier and Leo Reynaud and Antoine Wurcker

Abstract

SM3, the Chinese standard hash algorithm inspired from SHA2, can be attacker by similar means than SHA2 up to an adaptation to its differences. But this kind of attack is based on targeting point of interest of different kinds, some are end of computation results, that are stored when others are in intermediate computational data. The leakage effectiveness of the later could be subject to implementation choices, device type or device type of leakage. In this paper, we propose a new approach that targets only the first kind of intermediate data that are more susceptible to appear. As an example, we targeted the HMAC construction using SM3, where our method allows to recover the first half of the secret information. reducing the security of the HMAC protocol.