Impact of Aging on Template Attacks

Template attack is the most powerful side-channel attack from an information theoretic point of view. This attack is launched in two phases. In the first phase (training) the attacker uses a training device to estimate leakage models for targeted intermediate computations, which are then exploited in the second phase (matching) to extract secret information from the target device. Process variation and discrepancy of operating conditions (e.g., temperature) between training and matching phases adversely affect the success probability of the attack. Attack-success degradation is exacerbated when device aging comes into account. Due to aging, electrical specifications of transistors change over time. Thereby, if the training and target devices have experienced different usage time, the attack will be more difficult. Aging alignment between training and target devices is difficult as aging degradation is highly affected by operating conditions and technological variations. This paper investigates the effect of aging on the success rate of template attacks. In particular, we focus on NBTI and HCI aging mechanisms. We mount several attacks on the PRESENT cipher at different temperatures and aging times. Our results show that the attack is more difficult if there is an aging-duration mismatch between the training and target devices.