I'm implementing HTTP Message Signatures (RFC 9421) in Fedify, and although the signature base matches and the private–public key pair is correct, the signature verification keeps failing. I've wasted hours on this issue and still have no idea what's wrong. 😩

@hongminhee Do you have a branch for it? Maybe I can take a look later?

Hmm, test vectors for rsa-v1_5-sha256 made with httpsig.org seem something wrong…?