Encrypt all messages between nodes.

[macourtney]

Encrypt all messages between nodes. Currently, all connections are encrypted by i2p, but the public key of the user you talking to is not used to encrypt the data which could cause problems if we ever stop using i2p.

[aaannndddyyy]

That would also be needed if you use friends' friends to relay messages to offline friends. Not everyone will want to run their computer 24/7. And since masques is serverless, some other way of getting info from offline peers would be handy.
While an identity's stream messages are known to both friends and only need signing ( #55 ), personal messages - if relayed at all (metadata - do we want friends to know that we sent other friends a private message?) - need to be encrypted independently of the actual transport layer ( i2p ).
Maybe even relayed PM's could somehow be cloaked and hidden within something else? Some standard data you relay perhaps, but which contains some random element.

[aaannndddyyy]

Re my above comment: It could also be done in a torrent-like fashion. This way, you'd not even need to have common friends. An anonymous i2p dest simply searches for a certain user's content. In order to prevent third parties from tracking the amount of shared PM's of a given user, those should be tracked by a previously agreed-upon shared identifier.

( cf. http://nightweb.net )