A look at the latest post-quantum signature standardization candidates

The report analyzes NIST’s second-round post-quantum signature candidates (“signatures on ramp”) for TLS, comparing sizes and performance of schemes like ML-DSA, SLH-DSA, Falcon, HAWK, SNOVA, MAYO, FAEST, SQISign, and UOV, and assessing their feasibility for handshake and certificate use. Drawing on QUIC telemetry and prior experiments, it finds that added certificate bytes notably impact handshake times and typical connections, and proposes mitigations such as mixing schemes, reducing certificate chain signatures, exploring KEM-based authentication, and broader WebPKI changes. It notes ongoing deployment of post-quantum key agreement and plans to offer ML-DSA certificates when CA support arrives, while continuing to evaluate performance and security trade-offs.