Faster Post-quantum TLS 1.3 Based on ML-KEM: Implementation and Assessment

TLS is extensively utilized for secure data transmission over networks. However, with the advent of quantum computers, the security of TLS based on traditional public-key cryptography is under threat. To counter quantum threats, it is imperative to integrate Post-Quantum Cryptography (PQC) into TLS (PQ-TLS, for short). Most PQ-TLS research focuses on integration and evaluation, but few studies address the improvement of PQ-TLS performance by optimizing PQC implementation. As a critical part of PQ-TLS, post-quantum key encapsulation Mechanisms (PQ-KEMs) directly impact PQ-TLS handshake performance. ML-KEM is a NIST-standardized PQ-KEM. In this work, we explore how to improve ML-KEM performance using the latest Intel’s Advanced Vector Extensions instruction set AVX-512. We give our implementation details of parallelizing polynomial multiplication, modular reduction, and other computationally intensive modules strategically within ML-KEM. Our optimized ML-KEM implementation achieves up to 1.64 \(\times \) speedup compared to the latest AVX2 implementation. Based on our ML-KEM AVX-512 implementation, we introduce a novel batch key generation method for ML-KEM that can seamlessly integrate into the TLS protocols. The batch method accelerates the key generation procedure by 3.5 \(\times \) to 4.9 \(\times \) . Finally, we integrate the optimized AVX-512 implementation of ML-KEM into TLS 1.3 and assess handshake performance under both PQ-only and PQ-hybrid modes. The assessment demonstrates that our faster ML-KEM implementation results in a higher number of TLS 1.3 handshakes per second under both modes. To further investigate ML-KEM performance improvement, we revisit two IND-1-CCA KEM constructions proposed at Eurocrypt’22 and Asiacrypt’23, implement them based on ML-KEM and integrate the one of better performance into TLS 1.3 with benchmarks.