Even Signal took years to get it right, and Matrix is not quite there yet: Implementing a multi-device chat system that supports not only reliable encryption, but also reliable deletion of messages also known as "Forward Secrecy".

In this talk we'll present a new "Autocrypt 2 certificate" specification draft, that originated from the chatmail community and its supporters. The draft is built upon the modern RFC9850 OpenPGP standard and aims to to supports encryption that is safe against attackers that collect all in-transit traffic and then

• try to use a prospective future Quantum computer to decrypt all collected messages, or

• try to recover deleted messages after they get hold of a device/private key.

The draft Autocrypt2 certificate specification is designed to be usable by any Internet Messaging system and is intended for submission to IETF early 2026.