http://isdb4l77sjqoy2qq7ipum6x3at6hyn3jmxfx4zdhc72ufbmuq4ilwkqd.onion/blog/20220112-simplex-chat-v1-released.html
These keys and secrets are separate for each contact, group membership and file transfer. in addition to double ratchet, there is a separate E2E encryption in each message queue with DH key exchange using Curve25519 and NaCl crypto-box - separate E2E encryption has been added to avoid having any cipher-text in common between message queues of a single contact (to prevent traffic correlation). additional encryption of messages delivered from servers to recipients, also using Curve25519 DH...