The Energy Cost of Post-Quantum Transition: Benchmarking PQC Algorithms on Commodity Hardware

Abstract

The transition to quantum-resistant cryptography is becoming increasingly urgent as advances in quantum computing threaten widely deployed public-key systems such as RSA and elliptic-curve cryptography. While the National Institute of Standards and Technology (NIST) has recently standardized several post-quantum cryptographic (PQC) algorithms, there remains limited empirical data on their practical performance and energy characteristics on commodity hardware. This paper presents a comprehensive microbenchmark study of NIST-selected PQC key encapsulation mechanisms (ML-KEM, HQC, BIKE, Classic McEliece) and digital signature algorithms (ML-DSA, Falcon, and SPHINCS +). Using the liboqs library on an AMD Zen 4 platform, we measure CPU cycles, artifact sizes, peak memory usage, and energy consumption across multiple NIST security levels. Energy measurements are obtained through AMD µProf power traces using an idle-subtracted methodology to estimate per-operation dynamic energy. Our results show that lattice-based schemes (ML-KEM and ML-DSA) consistently provide the best performance and energy efficiency, while code-based alternatives exhibit specialized trade-offs, including extremely expensive key generation for Classic McEliece and higher computational cost for HQC. Hash-based signatures such as SPHINCS + demonstrate significantly higher signing overhead but offer conservative security assumptions. These findings provide practical insight into the trade-offs between runtime, energy efficiency, and artifact sizes across PQC families, offering system architects and engineers concrete data for evaluating deployment strategies in quantum-safe systems.