Implement GPG encryption upon reception

[arodier]

For emails confidentiality, it is possible to encrypt messages, using GPG, on reception, with a Postfix milter. After that, any mail client supporting GPG decryption should be able to decrypt the email.

This would prevent any user to read the messages received, even root.

There are probably many solutions available, I found this for now:

• https://github.com/letoams/openpgpkey-milter

[sorcer1122]

https://kb.mailbox.org/display/MBOKBEN/The+Encrypted+Mailbox
These guys use Sieve to implement encryption of incoming emails