mc-verify will verify the cleartext signature on a
message in the current buffer.
mc-read-mode binds this function
to C-c / v by default.
When this function is called, Mailcrypt will pass the message to PGP for processing and report whether or not the signature verified.
If the signature failed to verify because you lack the necessary public key, Mailcrypt will offer to fetch it for you (see Key Fetching).Decrypting General Use Snarfing Keys