**GPG Lacre** (wax seal in Portuguese) is a content filter for Postfix that automatically encrypts unencrypted incoming email using PGP or S/MIME for select recipients.
This project is the continuation of the work of "gpg-mailgate" on providing open source, GnuPG based email encryption for emails at rest. All incoming emails are automatically encrypted with user's public key before they are saved on the server. It is a server side encryption solution while the control of the encryption keys are fully at the hands of the end-user and private keys are never stored on the server.
The scope of the project is to improve on the already existing code, provide easy to use key upload system (standalone as well as Roundcube plugin) and key discoverability. Beside providing a solution that is easy to use we will also provide easy to digest material about encryption, how it works and how to make use of it in situations other the just mailbox encryption. Understanding how encryption works is the key to self-determination and is therefore an important part of the project.
- Public keys are stored in a dedicated gpg-home-directory
- Encrypts both matching incoming and outgoing mail (this means gpg-mailgate can be used to encrypt outgoing mail for software that doesn't support PGP or S/MIME)
- gpg-mailgate-web extension is a web interface allowing any user to upload PGP keys so that emails sent to them from your mail server will be encrypted (see gpg-mailgate-web directory for details)
This is a combined work of many developers and contributors. We would like to pay honours to original gpg mailbox developers for making this project happen, and providing solid solution for encryption emails at rest: