This extension makes use of the keyring of the current user. This keyring
is normally located in ~./.gnupg/.
To specify a custom location, store the path to the keyring in the
environment variable GNUPGHOME. See putenv for more information how to do
this.
Some functions require the specification of a key. This specification can
be anything that refers to an unique key (userid, key-id, fingerprint,
...).
This documentation uses the fingerprint in all examples.