ReadArmoredKey attempts to read the filepath and parses an armored GPG key.

ReadArmoredKeyFile attempts to read the filepath and parses an armored GPG key.

ReadPrivateKey attempts to read the filepath and parses an armored GPG private key.

ReadPrivateKeyFile attempts to read the filepath and parses an armored GPG private key.

Sign signs the provided data using the private key(s) in the entity list.

VerifySignature verifies the signature on the provided data using the public key(s).