The aim of this tip is to encrypt your messages via Thunderbird. This trick has been optimized for GNU/Linux Ubuntu, but the steps must be the same on the other distributions.
If you are using the GNOME desktop, click on Applications -> Ubuntu repositories. Install Thunderbird and Enigmail, an extension that enables encryption of messages (via GUI). Also check out if the gpg package exists.
If you want to set Thunderbird in another language, go to the menu System -> Administration and select language support. Open Thunderbird, and create your account.
Configuration and generating the of set of encryption keys
In Thunderbird, open the Tools menu/Extensions, then select Preferences and then Enigmail. In the General tab, make sure you have "GnuPG found in /usr/bin/gpg "
Open the Edit menu and select Account Settings and find the section corresponding to the email account you have configured. Go to OpenPGP security subcategory and choose Enable OpenPGP(Enigmail) support for this account. Remember to check the Always use PGP/MIME option.
In Thunderbird, open the Enigmail menu and select Key Management.
In the window that opens, do Generate -> New Pair of Keys. Select your e-mail, type a password, and generate the key.
Publishing the public key
In the previously opened window, search your e-mail address in the search bar. Then, right click -> Send the public key on a keyserver. Try to send it on at least two or three public key servers.
Sending a signed encrypted message
Encryption guarantees the confidentiality of the content and the signature is a proof of the identity of the sender. To send a test message:
Click on Write and type a message (which you will send to yourself, as a test).In the OpenPGP menu, select the Encrypt and Sign message. Send the message.
Then open the message through Thunderbird.
Normally, a message appears at the top: Decrypted message; Signature of ....email address of sender!