pqm4: Benchmarking NIST Additional Post-Quantum Signature Schemes on Microcontrollers

In July 2022, the US National Institute for Standards and Technology (NIST) announced the frst set of Post-Quantum Cryptography standards: Kyber, Dilithium, Falcon, and SPHINCS+. Shortly after, NIST published a call for proposals for additional post-quantum signature schemes to complement their initial portfolio. In 2023, 50 submissions were received, and 40 were accepted as round-1 candidates for future standardization.

In this paper, we study the suitability and performance of said candidates on the popular Arm Cortex-M4 microcontroller. We integrate the suitable implementations into the benchmarking framework pqm4 and provide benchmarking results on the STM32L4R5ZI featuring 640 KB of RAM. pqm4 currently includes reference implementations for 15 submissions and M4-optimized implementations for fve submissions. For the remaining candidates, we describe the reasons that hinder integration – the predominant reason being large key size or excessive memory consumption.