Migrating legacy users

Legacy users (without MailCrypt keys) continue to work without mailbox encryption. If they generate a recovery token manually in the account settings, a MailCrypt key pair gets created for them. This doesn't enable MailCrypt for them automatically, though. Reason is that this would result in acounts with partially unencrypted (the old) and partially encrypted (the new) mails. Therefore we decided to leave the exercise to enable MailCrypt for legacy users who got a MailCrypt key pair generated in the meantime to the system admins (e.g. by a cron script).

In order to enable MailCrypt for a legacy user, do the following:

1. Ensure that they have a recovery token generated. This will automatically generate MailCrypt key pair as well. This step can only be done by the account holder, as the user password is required to do so.
2. Manually set mail_crypt=1 for the user in the virtual_users database table. This needs to be done on a per-user basis on purpose (e.g. by a cron script).

Or, alternatively, to enforce MailCrypt for all legacy users:

1. Set MAIL_CRYPT=3 in the dotenv (.env) file. This will result in a MailCrypt key pair being generated automatically when legacy users log in the next time. Again, we cannot do this step without the user logging in, as the user password is required to do so.
2. Manually set mail_crypt=1 for all users in the virtual_users database table that have a MailCrypt key pair generated but MailCrypt not enabled yet. This needs to be done on a per-user basis on purpose (e.g. by a cron script).

Please note that existing mails will not be encrypted automatically. Instead, all existing mail stays unencrypted and only new incoming mail will be stored encrypted.

In bin/mailcrypt-encrypt-maildir you find a script to encrypt unencrypted mail from legacy mailboxes that already have a MailCrypt key configured. This script needs to be invoked as a user who has write access to the mailbox in question - probably the best is to run it as root:

./bin/mailcrypt-encrypt-maildir user@example.org

The following SQL statement can be used to enable MailCrypt for all legacy users that got a MailCrypt key pair generated. Use with caution!

UPDATE virtual_users SET mail_crypt=1 WHERE mail_crypt_secret_box IS NOT NULL AND mail_crypt = 0;

We might add a migration script to encrypt old mails from existing users at a later point.