ApproPower: Characterizing the Power Side-Channel Features of Approximate Multipliers With Symbolic Path Analysis

Approximate computing has garnered significant attention due to its potential to reduce power consumption, enhance performance, and simplify circuit design. However, the security implications of applying approximate computing techniques remain largely unexplored. Identifying all possible vulnerabilities in approximate designs is very challenging. One of the challenges stems from the lack of insightful methodologies and metrics to perform a precise security evaluation. This paper presentsApproPower, a security-driven framework for pre-silicon evaluation of power side-channel leakage in approximate multipliers.ApproPowerenables an analysis of how approximation techniques influence power side-channel leakage and employs symbolic path analysis to estimate delay-dependent power leakage behaviors at design time. Using a set of open-source approximate multipliers, we examine the relationship between data precision, approximate strategies, and measured power leakage. Our results show that symbolic path analysis provides useful guidance for identifying potential power side-channel risks. We also observe that some approximate designs can offer improved resource efficiency while exhibiting reduced leakage; for instance, in themul7x7uset, a majority of benchmark circuits demonstrate lower leakage after approximation, withmul7x7u_03Machieving a 35% reduction in resource usage compared tomul8x7u_3C6.