I built a totally decentralized and secure P2P/DHT communications platform a long time ago called DeOps - https://github.com/swax/DeOps

It let's members of a group create a totally private darknet with a hierarchy of trust among themselves using a chain of signed trust tokens. All packets are encrypted with the key of the receiver and signed by the sender. It even uses random ports and sends filler traffic between nodes to prevent finger printing.

I built on top of it services like IM, VOIP, chat rooms, a versioned file system, mail, message boards, etc.. I had a lot of free time lol. The nodes automatically manage the storage of data around the DHT.