# ssb-private-groups ## receive key to indicate you support box2, post a message ``` { type: 'private-msg-key', key: curve25519.public } `` when decrypting messages from another feed, you know it came from their most recent private message key, because they are in a strict order. when decrypting messages _for your feed_ these must be combined with each private-msg-key you retain. when rotating keys, it is advisable to keep both keys alive for an overlap period, to improve chances that sender has your new key when they write a message to you. If they write a message to a key you have discarded, you won't know, because you'll be unable to decrypt that message. ## License MIT