Raven

Decentralized messaging network that anyone can broadcast/subscribe messages anonymously.

Anonymity is achieved by implementing Dandelion protocol on top of libp2p's pub/sub module, dandelion is a privacy preserving protocol to make message sender anonymous, it has 2 phases, the first phase is stem phase, where messages go through a psuedo-random path, the second phase is fluffing, when the message reaches the last node(randomly chosen), the message is diffused to its surrounding peers, so the third party observer cannot track back the node original node who send the message, because the message is relayed through an anonymous graph. Message broadcasting is implemented by libp2p floodsub. libp2p-pubsub-dandelion: https://github.com/rairyx/go-libp2p-pubsub/tree/dandelion

Demo

Directory: pubsub

What it demonstrates: Two Go peers, one JS peer, and one Rust peer are all created and run a chat server using a shared PubSub topic. Typing text in any peer sends it to all the other peers.

Quick test: cd pubsub and then run ./test/test.sh. Requires Terminator (eg, sudo apt-get install terminator). The rest of this section describes how to test manually.

(TODO: maybe eliminate centralized bootstrapper; any peer could then bootstrap from any other peer and peers could start in any order; downside is the code will be more complex in all peers)

First terminal: Create the bootstrapper node

cd pubsub
./pubsub-interop ../util/private_key.bin.bootstrapper.Wa --bootstrapper

The bootstrapper creates a new libp2p node, subscribes to the shared topic string, spawns a go routine to emit any publishes to that topic, and then waits forever.

(Note that the node ID of pubsub-interop is going to be Qm...6aJ9oRuEzWa. Node IDs in libp2p are just public keys, and the public key Qm...6aJ9oRuEzWa is derived from the private key file ../util/private_key.bin.bootstrapper.Wa. That file is just an X.509 keypair generated by the included program util/private-key-gen). We use fixed public/private keypairs for each node in this example to keep things simple.)

Second terminal: Create a go peer to connect to bootstrapper and publish on the topic

cd pubsub
./pubsub-interop ../util/private_key.bin.peer.Sk

This peer, which is not in bootstrapper mode, creates a node, subscribes to the shared topic string, spawns the same go routine, and then loops forever requesting user input and publishing each line to the topic.

Third terminal: Create a JS peer to connect to bootstrap and publish on topic

cd pubsub/js
npm install  # first time only
node index.js /ip4/127.0.0.1/tcp/5555/ipfs/QmehVYruznbyDZuHBV4vEHESpDevMoAovET6aJ9oRuEzWa

This JS peer will accept lines of text typed on stdin, and publish them on the PubSub topic.

(Note that the JS peer generates a new identity (public/private keypair) each time, and prints its public key to stdout. This is a deficiency in the demo; to be consistent with the Go code it should accept a private key on the CLI.)

Fourth terminal: Creates a Rust peer to connect to the bootstrap node and then subscribe and publish on the topic:

cd pubsub/rust
cargo run

The Rust peer starts up, listens on port 6002, and then dials the boostrap peer. (TODO: rust-libp2p#471) It is now subscribed to the same topic as the other peers.

If you return to the second, third or fourth terminals and type a message, the bootstrapper and the other 2 peers will all print your message.

Conclusion

You now have a chat app on a private libp2p network where each node can exchange messages anonymously using PubSub.

Debugging Notes

JS To see debug messages from the Node.js program, use the DEBUG environment variable:

DEBUG="libp2p:floodsub*,libp2p:switch*,mss:*" node index.js [args...]

Go To see debug messages in Go programs, do this at runtime:

IPFS_LOGGING=debug ./pubsub-interop [args...]

(TODO: describe custom instrumenting the local go code for complex debugging)

If you instrument your go code with custom fmt.Println's, then revert back like this:

cd $GOPATH
go get -u ./...

Other useful commands:

go get -u github.com/libp2p/go-libp2p-kad-dht   # fetch just Kad DHT repo

Acknowledgements: @jhiesey for DHT (content & peer routing) JS+Go interop, @stebalien for PubSub