Side-Channel Analysis of Lightweight Ciphers: Does Lightweight Equal Easy?

Side-channel attacks represent a powerful category of attacks against cryptographic devices. Still, side-channel analysis for lightweight ciphers is much less investigated than for instance for AES. Although intuition may lead to the conclusion that lightweight ciphers are weaker in terms of side-channel resistance, that remains to be confirmed and quantified. In this paper, we consider various side-channel analysis metrics which should provide an insight on the resistance of lightweight ciphers against side-channel attacks. In particular, for the non-profiled scenario we use the theoretical confusion coefficient and empirical correlation power analysis. Furthermore, we conduct a profiled side-channel analysis using various machine learning attacks on PRESENT and AES. Our results show that the difference between AES and lightweight ciphers is smaller than one would expect. Interestingly, we observe that the studied 4-bit S-boxes have a different side-channel resilience, while the difference in the 8-bit ones is only theoretically present.