LiCSPA: Lightweight Countermeasure against Static Power Side-Channel Attacks

This paper presents LiCSPA, a novel defense strategy against a critical threat to cryptographic hardware in modern technology nodes: static power side-channel attacks. Our method is based on (1) carefully tuning high-Vth versus low-Vth cell selection as well as driver strengths during synthesis, accounting for both security and timing impact, and (2), at runtime, randomly switching the operation between these cells. By doing so, LiCSPA achieves to significantly obscures data-dependent static power patterns. Our experimental results on a commercial 28nm node show a drastic increase in the effort required for a successful attack, namely up to 96 times more traces. LiCSPA incurs little cost, namely only 6% in area, making it a lightweight and practical defense that excels prior art.