Comparative analysis of post-quantum handshake performance in QUIC and TLS protocols

The rapid advancement of quantum computing threatens the security foundations of today’s communication protocols. On the web, the traditional approach to securing web traffic has been to couple HTTP with TLS over TCP, but QUIC over UDP has recently emerged as an alternative to reduce latency and improve performance over unreliable networks. The need for an urgent transition to quantum-resistant web protocols demands further examination of both stacks. Consequently, in this work we evaluate their performance when combined with post-quantum primitives. To this end, we devise a practical evaluation framework that integrates the cryptographic primitives into TLS and QUIC implementations. Our analysis focuses on comparing the impact of hybrid and post-quantum primitives on TLS and QUIC under both ideal and realistic network conditions, providing quantitative insights into the performance cost and feasibility of transitioning toward a post-quantum web. Our results indicate that hybrid KEMs incur the highest handshake latency and bandwidth overhead, while pure post-quantum KEMs offer a favorable trade-off between security and performance, with only moderate costs. Moreover, QUIC consistently reduces the performance penalty of post-quantum primitives compared to TLS, especially in lossy network environments.