eprint.iacr.orgpaper

Role-Specific Signature Placement in TLS 1.3: Cost Propagation and PQC Migration

An IACR eprint paper evaluating all 13-cubed ways to assign 13 post-quantum/traditional signature parameter sets across the Root, Intermediate and Leaf roles of a TLS 1.3 certificate chain, holding the algorithm set fixed and varying only placement. Across 286 three-algorithm groups, median max/min ratios reach 2.085x for TLS handshake latency, 4.310x for certificate body size and 4.551x for path-validation cost purely from role order, with Leaf placement mattering far more than Root/Intermediate swaps. It also shows that looking only at Certificate-message size can misrank candidates such as ML-DSA-65 versus SLH-DSA-SHAKE-192s once the Leaf signature in CertificateVerify and full authentication-path cost are included, arguing PQC certificate-chain design must account for role-specific cost under real network/load conditions.