cable-handshake.ts (WIP)

Implements 1.0-draft5 of the Cable Handshake Protocol.

WARNING: Incomplete! Still in draft status.

API

import { Handshake } from 'cable-handshake.ts'

Handshake.generateKeyPair(): NoiseState.KeyPair

Static method to generate a new public/private keypair.

new Handshake(key, psk, initiator, stream)

Create a new Cable Handshake instance.

• key <NoiseState.KeyPair>: A public/private keypair for this peer.
• psk <Buffer>: A 32-byte buffer containing the pre-shared key of the Cabal to join or create.
• initiator <boolean>: true if this instance is initiating the handshake. One side MUST be initiator and the other MUST be responder (false).
• stream <Duplex>: The duplex stream that facilitates communication with the remote peer with which to handshake.

handshake.handshake(): Promise<PostHandshakeTransport>

Exchanges the necessary protocol messages with the remote peer to establish a secure transport.

postHandshakeTransport.write(bytes: Buffer)

Writes an encrypted message to the remote peer.

postHandshakeTransport.recv(): Promise<Buffer>

Reads an encrypted message from the remote peer.

postHandshakeTransport.destroy()

Terminates the connection to the remote peer gracefully. This includes sending an end-of-stream marker so the remote knows it was an intentional close.

Example

import { Handshake } from '../src/handshake.js'
import net from 'net'

const PSK = Buffer.alloc(32).fill(0x08)

async function client() {
  const key = Handshake.generateKeyPair()
  console.log('Client is', key.publicKey.toString('hex'))

  const socket = net.connect({ host: 'localhost', port: 7500 })

  const hs = new Handshake(key, PSK, true, socket)
  const tx = await hs.handshake()

  tx.write(Buffer.from('Hello Cable world!'))

  socket.once('close', () => {
    console.log('client socket closed')
  })
}

async function server() {
  const key = Handshake.generateKeyPair()
  console.log('Server is', key.publicKey.toString('hex'))

  const server = net.createServer(async socket => {
    const hs = new Handshake(key, PSK, false, socket)
    const tx = await hs.handshake()

    socket.once('close', () => {
      console.log('server socket closed')
      server.close()
    })

    const msg = await tx.read()
    console.log('Server recv\'d:', msg.toString())

    tx.destroy()
  })

  server.listen(7500, undefined, undefined, () => console.log('Listening on 0.0.0.0:7500'))
}

server()
client()

outputs

Server is 7c6299bc61c3da52eeaba3d8ba606b6ddfeeabaabedcd1e292eca40613dcc41d
Client is 4fe9e664a76974940f3611b1efa8fdd6254508b4ca55e36177ebbc3757b53030
Listening on 0.0.0.0:7500
Server recv'd: Hello Cable world!
server socket closed
client socket closed

Command Line Interface (CLI)

One can be found in ./examples/cli.ts for testing or debug purposes. It uses stdin and stdout for communication. Two instances of this program could be piped into each other using dupsh:

$ tsc
$ export PSK=4fccf9a246e0e14b440a9faa1119e9fed42e0dd8a4ce6d54b73f843c60f57b88
$ dupsh \
  'node examples/cli.js $PSK initiator "British Left Waffles on Falkland Islands"' \
  'node examples/cli.js $PSK responder "The duke yet lives that Henry shall depose"'

Debug Output

This module uses debug. Debug output may be viewed by setting the DEBUG environment variable in your shell to, e.g.

export DEBUG=cable-handshake:*   # short for DEBUG=cable-handshake:I,cable-handshake-R

The two used debug namespaces are cable-handshake:I for the handshake initiator, and cable-handshake-R for the responder.

Notes

This module hasn't been tested in an environment other than Node.js. Buffers are used and haven't been tested against Uint8Arrays on the browser. Making this module work in the browser would be a welcome contribution!

License

AGPL-3.0