OpenPGP Applet is a graphical frontend on top of GnuPG.

It allows encryption and decryption of the clipboard's content either with public key cryptography, or with a symmetric cipher using a passphrase. Creating and verifying clear text signatures is also supported.

Note: OpenPGP Applet does not handle passphrase input. Since it also does not offer terminal interaction unless explicitly run from there, it relies in practice on GnuPG agent to be running and configured to use a passphrase entry dialog, such as pinentry-gnome3.