cable-handshake.ts

Implements 1.0-draft7 of the Cable Handshake Protocol.

Install

npm install cable-handshake.ts

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): Promise<void>

Writes an encrypted message to the remote peer.

postHandshakeTransport.read(): Promise<Buffer>

Reads an encrypted message from the remote peer.

If the empty buffer is returned, it means the other side has requested to end the session. Proper etiquette is to call postHandshakeTransport.writeEos() and not perform any further writes.

postHandshakeTransport.writeEos(): Promise<void>

Writes the protocol's end-of-stream marker (an empty payload).

Proper etiquette is to wait to receive the remote peer's end-of-stream marker, by calling postHandshakeTransport.readEos(). There is no guarantee it will arrive.

postHandshakeTransport.readEos(): Promise<void>

Reads from the stream, expecting the next message to be an end-of-stream marker. If something else is instead received, the promise rejects. There is no guarantee the other side will end an end-of-stream marker.

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()

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

  await tx.readEos()
  await tx.writeEos()
  console.log('Client closed gracefully')

  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())

    await tx.writeEos()
    await tx.readEos()
    console.log('Server closed gracefully')
    socket.end()
  })

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

server()
client()

outputs

Server is 8dc696e108f09a95582d7c9f1f8a3c8bf2d77a5dca4a5fbd4ca668a7229fdd78
Client is 0ff02476d24619f4e34d2963a8f010121e447ed543133c248d9d926f0fbd1c69
Listening on 0.0.0.0:7500
Server recv'd: Hello Cable world!
Client closed gracefully
Server closed gracefully
Client socket closed
Server 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!

Development Dependencies

The Rust integration tests require at least rustc >= 1.75.0 and cargo >= 1.75.0.

License

AGPL-3.0