Mozilla Thunderbird is getting a big update that will include built-in email encryption using OpenPGP. Now you can opt out of addons such as Enigmail and Mailvelope. The implementation of encryption is based on the developments of the Enigmail add-on, the author of which helps the Mozilla team in transferring functionality to the mail client.
The main difference is that instead of using an external GnuPG program, it is proposed to use its own implementation of the OpenPGP library.
It also offers its own key store, which is not compatible with the GnuPG key file format and is protected by a master password, which is used to protect S/MIME accounts and keys.
Source: linux.org.ru