Encrypted mail for the graphical desktop environment

In this example, we will configure the popular Evolution mail client in a graphical desktop environment to be able to keep privacy by using OpenPGP (PGP, GnuPG, GPG) for signing and encryption. The Evolution mail client is the default mail client on a Ubuntu operating system.

We assume, that the mail server settings has been configured and tested prior to this procedure.

We also assume, that we have a valid private (secret) key.

If we have not already done so, we insert our private key and our friends public keys into the local key rings using the GnuPG command line utility.

gpg --list-keys
gpg --import private_key.asc
gpg --import anns_public_key.asc
gpg --import bobs_public_key.asc
gpg --list-keys

We open the Evolution mail client, press Ctrl-Shift-S to enter our preferences, press Alt-E to edit our mail account and click the security tab. In the field “PGP/GPG Key ID” we enter the hexidecimal ID of our private key. We prefix it with 0x. We assure, that our outgoing messages are always signed, and, that our key ring can be trusted when encrypting. We click “OK” and close our preferences.

We want to test the signing. We prepare a message, click “Security”, ensure, that “PGP Sign” is checked, and send it. The mail client asks for the pass phrase. We enter the pass phrase. The recipient receives our message, opens it and find, that the mail client has validated the signature against the local public key. If there is no trustworthy path available to the key of the sender, it is normal, that the sender can not be verified.

We want to test the signing and encryption. We assure, that we have imported the public key of the recipient prior to this. Again, we prepare a message, but this time, we apply encryption by clicking “Security” and selecting “PGP Encrypt” as well as “PGP Sign”. The recipient receives our message, opens it and the mail client asks for the pass phrase. When entered, the decrypted message and validation appears.