Paper 2019/536

Protecting against Statistical Ineffective Fault Attacks

Abstract

At ASIACRYPT 2018 it was shown that Statistical Ineffective Fault Attacks (SIFA) pose a threat for many practical implementations of symmetric primitives. In particular, countermeasures against both power analysis and fault attacks typically do not prevent straightforward SIFA attacks that require only very limited knowledge about the concrete attacked implementation. Consequently, the exploration of countermeasures against SIFA that do not rely on protocols or physical protection mechanisms is of great interest. In this paper, we explore different countermeasure strategies against SIFA. First, we introduce an abstraction layer between the algorithmic specification of a cipher and its implementation in hardware or software to study and describe resistance against SIFA. We then show that by basing the masked implementation on permutations as building blocks, we can build circuits that withstand single-fault SIFA and DPA attacks. We show how this approach can be applied to 3-bit, 4-bit, and 5-bit S-boxes and the AES S-box. Additionally, we present a strategy based on fine-grained fault detection suitable for protecting any circuit against SIFA attacks. Although this approach may lead to a higher implementation cost due to the fine-grained detection needed, it can be used to protect arbitrary circuits and can be generalized to cover multi-fault SIFA.