Contains the result of a signature verification.
GoodChecksum(Signature, &'a TPK, &'a Key, Option<&'a Signature>, RevocationStatus<'a>)
The signature is good.
Note: A signature is considered good if it can be mathematically verified. This doesn't mean that the key that generated the signature is in anyway trustworthy in the sense that it belongs to the person or entity that the user thinks it belongs to. This can only be evaluated within a trust model, such as the web of trust (WoT).
Unable to verify the signature because the key is missing.
The signature is bad.
type Error = Infallible
The type returned in the event of a conversion error.