The world is not enough: Another look on the constructions of comparison-based distinguishers

Partition-based and comparison-based distinguishers are two types of side-channel distinguishers. Here, compared with partition-based distinguishers, the constructions of comparison-based distinguishers are simpler, their efficiencies are higher, and they are less picky about leakage models. Therefore, comparison-based distinguishers are widely used in the attack scenario to recover the secret key used by a cryptographic device. However, comparison-based distinguishers rely on the assumptions of normal distribution and linear relationship, if these assumptions do not hold, their efficiencies decrease. Tie, outlier, and extreme can also decrease the efficiencies of comparison-based distinguishers. In light of this, this work proposes four distinguishers TieGiniHM, TieGiniSYM, Tau-b, and Gamma. They do not rely on the assumptions of normal distribution and linear relationship, can avoid the problem of tie, and are resilient to outlier and extreme. The efficiencies of the proposed distinguishers are evaluated in both the simulated scenario and the real scenario. According to the evaluation results, the efficiencies of four distinguishers can be higher than existing partition-based and comparison-based distinguishers. Apart from that, four distinguishers are less picky about leakage models than existing comparison-based and partition-based distinguishers. Overall, this work provides side-channel analyzers useful tools to accurately evaluate the security of a cryptographic device in the side-channel analysis scenario.