There's nothing a library can add to make things "safer" when it comes to application-specific constraints. If I'm checking to make sure I only accept a specif

There's nothing a library can add to make things "safer" when it comes to application-specific constraints. If I'm checking to make sure I only accept a specific algorithm, I'm not going to blame a crypto library for validating something that is technically accurate (short of maybe disabling the "none" algorithm by default). You should also be in possession of at least the public key beforehand, and rely on that for authentication, rather than anything in the claim.