Improved Correlation Power Analysis Attack on the Latest Cortex M4 Kyber Implementation

CRYSTALS-Kyber has been standardized as a general public-key post-quantum algorithm under the name of ML-KEM after NIST released its first three final post-quantum standards in August 2024. The resilience of post-quantum cryptography to side-channel attacks has been an important research endeavor, and there have been many attacks designed, including basic Correlation Power Analysis. This paper adapts existing Correlation Power Analysis attacks to the most recent ARM Cortex M4 optimized implementation that uses Plantard arithmetic. It also demonstrates an improved version of a CPA that results in a 50% speedup compared to the original attack. Data are gathered and the mathematical model is tested using a ChipWhisperer-Lite board.