Leakage Power Analysis attacks: Effectiveness on DPA resistant logic styles under process variations

In this paper, the effectiveness of the recently proposed Leakage Power Analysis (LPA) attacks to cryptographic circuits is analyzed in the presence of process variations. Reference circuits (e.g., S-BOX, crypto core) were designed in various logic styles, and their robustness against LPA attacks was comparatively evaluated through Monte Carlo simulations in 65 nm. Analysis allowed for better understanding the impact that process variations have on the outcome of LPA attacks, which is an aspect that is not understood currently. Results show that LPA attacks are rather effective also under die-to-die and within-die process variations. Moreover, the comparison between different logic styles showed that standard CMOS logic circuits are extremely vulnerable to LPA attacks. Other logic styles that are robust against traditional Differential Power Analysis (DPA) attacks were also compared. Interestingly, analysis showed that these logic styles are still vulnerable to LPA attacks. Hence, LPA attacks are an even greater threat to Smart Cards information security, compared to DPA attacks. Moreover, traditional methods to protect Smart Cards against DPA attacks are ineffective in counteracting LPA attacks, thereby showing that a significant research effort will be needed to counteract LPA attacks with suitable solutions that ensure high security standards.