Scuttlebot is an open source peer-to-peer log store used as a database, identity provider, and messaging system. It has:

Global replication File-syncronization End-to-end encryption

Patchwork is Scuttlebot based and is…

End-to-end encrypted mail. Public social feeds. No central servers. Sync over WiFi. Offline operation. GPL licensed.

https://scuttlebot.io