A Secure and Efficient Implementation of the FALCON BaseSampler Against Side-Channel Attack

Abstract

With the advent of quantum computing threatening the existing public-key cryptosystems, the U.S. National Institute of Standards and Technology (NIST) has been leading the standardization effort for Post-Quantum Cryptography. FALCON, one of the digital signature algorithms selected in this process, is notable for its high efficiency. However, its core component, the BaseSampler, is known to be vulnerable to Simple Power Analysis (SPA).In this paper, we propose a new implementation method of the FALCON BaseSampler to counteract this vulnerability. Our approach involves modifying the existing RCDT and altering the specific operation that causes an underflow. Through practical experiments conducted with ChipWhisperer and Cortex-M4 board, we verify that the proposed countermeasure effectively establishes robustness against the known vulnerability.