Charge based power side-channel attack methodology for an adiabatic cipher

SIMON is a block cipher developed to provide flexible security options for lightweight hardware applications such as the Internet-of-things (IoT). Safeguarding such resource-constrained hardware from side-channel attacks poses a significant challenge. Adiabatic circuit operation has recently received attention for such applications due to ultra-low power consumption. In this work, a charge-based methodology is developed to mount a correlation power analysis (CPA) based side-channel attack to an adiabatic SIMON core. The charge-based method significantly reduces the attack complexity by reducing the required number of power samples by two orders of magnitude. The CPA results demonstrate that the required measurements-to-disclosure (MTD) to retrieve the secret key of an adiabatic SIMON core is 4× higher compared to a conventional static CMOS based implementation. The effect of increase in the target signal load capacitance on the MTD is also investigated. It is observed that the MTD can be reduced by half if the load driven by the target signal is increased by 2× for an adiabatic SIMON, and by 5× for a static CMOS based SIMON. This sensitivity to target signal capacitance of the adiabatic SIMON can pose a serious concern by facilitating a more efficient CPA attack.