Biblio

When implemented on real systems, cryptographic algorithms are vulnerable to attacks observing their execution behavior, such as cache-timing attacks. Designing protected implementations must be done with knowledge and validation tools as early as possible in the development cycle. In this article we propose a methodology to assess the robustness of the candidates for the NIST post-quantum standardization project to cache-timing attacks. To this end we have developed a dedicated vulnerability research tool. It performs a static analysis with tainting propagation of sensitive variables across the source code and detects leakage patterns. We use it to assess the security of the NIST post-quantum cryptography project submissions. Our results show that more than 80% of the analyzed implementations have at least one potential flaw, and three submissions total more than 1000 reported flaws each. Finally, this comprehensive study of the competitors security allows us to identify the most frequent weaknesses amongst candidates and how they might be fixed.

Probing attacks are serious threats on integrated circuits. Security products often include a protective layer called shield that acts like a digital fence. In this article, we demonstrate a new shield structure that is cryptographically secure. This shield is based on the newly proposed SIMON lightweight block cipher and independent mesh lines to ensure the security against probing attacks of the hardware located behind the shield. Such structure can be proven secure against state-of-the-art invasive attacks. For the first time in the open literature, we describe a chip designed with a digital shield, and give an extensive report of its cost, in terms of power, metal layer(s) to sacrifice and of logic (including the logic to connect it to the CPU). Also, we explain how “Through Silicon Vias” (TSV) technology can be used for the protection against both frontside and backside probing.