Non-Profiled Side-Channel Assisted Fault Attack: A Case Study on DOMREP

Abstract

Recent work has shown that Side-Channel Attacks (SCA) and Fault Attacks (FA) can be combined, forming an extremely powerful adversarial model, which can bypass even some strongest protections against both FA and SCA. However, such strongest form of combined attack comes with some practical challenges - 1) a profiled setting with multiple fault locations is needed; 2) fault models are restricted to single-bit set-reset/flips; 3) the input needs to be repeated several times. In this paper, we propose a new combined attack strategy called SCA-NFA that works in a non-profiled setting. Assuming knowledge of plaintexts/ciphertexts and exploiting bitsliced implementations of modern ciphers, we further relax the assumptions on the fault model, and the number of fault locations - random multi-bit fault at a single fault location is sufficient for recovering several secret bits. Furthermore, the inputs are allowed to be varied, which is required in several practical use cases. The attack is validated on a recently proposed countermeasure called DOMREP, which individually provides SCA and FA protection of arbitrary order. Practical validation for an open-source masked implementation of GIMLI with DOMREP extension on STM32F407G, using electromagnetic fault and electromagnetic SCA, shows that SCA- NFA succeeds in around 10000 measurements.