What Is Now Possible? Security Evaluation on Univariate DPA Attacks With Inaccurate Leakage Models

Success Rate (SR) is one of the most popular side-channel security metrics measuring the efficiency of key recovery. Theoretical expression of success rate reveals the functional dependency between relevant parameters such as number of measurements and Signal-to-Noise Ratio (SNR), helping researchers understand the resistance of a given implementation rapidly. However so far, existing works have exposed fundamental problems: (1) Evaluation is confined to a very limited range of distinguishers and specialized methods; (2) Evaluation assumes a perfect leakage model that is detached from reality. It is widely observed that an inaccurate leakage model will lead to a degraded or even distorted success rate. In this paper, we tackle above problems by introducing a novel framework which is able to evaluate seven side-channel distinguishers with a unified expression. Among them, we explore four new distinguishers that have not been investigated in the existing literature. Within the framework, DPA distinguishers are intuitively understood as linear maximum likelihood attack testing closeness between vectors with some easy-to-comprehend geometric metrics. Our evaluation is able to deal with profiled models of any quality and is agnostic to model profiling techniques. It uniquely enables the evaluation of success rates under inaccurate leakage models, whilst providing an (indirect) answer to the open question “how much information is lost due to the model biases” through quantifying the degradation of success rates. Finally, we formulate a set of criterion values for quantitative analyses of the model biases. It provides theoretical evidences for a more thorough explanation for the various behaviors of DPA attacks. Experimental results are inline with the theory, confirming its practical applicability.