Check out librevault, it does encrypted file sync using a DHT to find peers, allows for encrypted-only nodes which cannot decrypt your files (so you can throw t

Check out librevault, it does encrypted file sync using a DHT to find peers, allows for encrypted-only nodes which cannot decrypt your files (so you can throw them up on cheap VPSes, or friend's machines without worry) and in a nice open source package. Only catch so far is that the file indexing seemed kind of slow compared to SyncThing last time I tried it.