Glossary
What is a double ratchet?
The Double Ratchet is an algorithm that derives a new encryption key for every message, giving conversations forward secrecy and post-compromise security.
Two "ratchets" turn together: a symmetric-key ratchet advances with each message, and a Diffie-Hellman ratchet mixes in fresh key material whenever the conversation changes direction. Each key is used once and thrown away.
This is the same algorithm that secures Signal. PrivaMesh keeps it (paired with AES-256-GCM and message padding) so that a leaked key can neither unlock your past messages nor keep an attacker in your future ones.