Paper 2026/1938 Original: eprint.iacr.org/2026/1938 ↗

A Post-Quantum Cryptography Recommendation System with TLS Validation for Heterogeneous Environments

Abstract

The choice of a post-quantum cryptography (PQC) algorithm for a concrete deployment is governed by device performance, network conditions, and the practical constraints of TLS stacks, factors that algorithm-centric guidance does not capture. This paper presents a recommendation system that ranks key-encapsulation and signature candidates using benchmarks measured on the target machines and a physically grounded cost model, and confirms as recommended only those candidates that pass end-to-end TLS handshake validation. In experiments on three hardware placements composed of macOS, Linux, and Raspberry Pi machines, the recommended signature algorithm at NIST security level 3 reverses with the server hardware. Handshakes whose server flight exceeds the initial congestion window incur an additional 124 ms on a 160 ms link, far more than the 44 ms attributable to the extra bytes alone. The validation gate further exposes deployment obstacles invisible to microbenchmarks: a standardized signature scheme whose certificates are issued but rejected by the TLS stack, and a wire-format incompatibility between generations of the same crypto provider.