Peerjs with peerID validation by using ed25519

client.js

import Peer from "peerjs"
import * as ed from "@noble/ed25519";
import { Buffer } from "buffer"

(async function() {
  const privateKey = ed.utils.randomPrivateKey()
  const _message = Date.now().toString(16)
  const message = Uint8Array.from(Buffer.from(_message, "hex"))
  const publicKey = await ed.getPublicKey(privateKey)
  const peerId = Buffer.from(publicKey).toString("hex")
  const signature = await ed.sign(message, privateKey);
  const _signature = Buffer.from(signature).toString("hex")

  window.myPeer = new Peer(peerId, {
    debug: 3,
    token: `ed25519|${_signature}|${_message}`,
    host: 'localhost',
    port: 9000,
    path: '/api'
  });
})()

example-data.md

Example payload of the client

{
  id: '621843f72d062b5f94b5c928cae92382711090dc0d22b55ef5a51ca0b1f8482e'
  token: 'ed25519|733bed773f5821caf27d0c12ee43b589ce508db2326fedf4c5d44f8d8b2dae716f128b059d732b879d7bfc1b59e7ccd1d13b3336db23f5e4e85b89519a66760a|17ef87ecc06'
}

server.js

const ed = require('@noble/ed25519')
const express = require('express')
const ExpressPeerServer = require('peer').ExpressPeerServer
const PORT = process.env.PORT | 9000

const app = express()
const server = app.listen(PORT)

peerServer = ExpressPeerServer(server, {
	debug: true
})

app.use('/api',peerServer)

peerServer.on('connection', async function(connection) {
	const { id, token } =  connection
	if (id.length == 64 && id.match(/[^0123456789abcdef]/) == null) {
		const [mode, signature, message] = token.split('|')
		if (mode === 'ed25519') {
			date = new Date(parseInt(message, 16))
			// check if message (timestamp) is not older than 60 seconds
			if (date.getTime() + 1000 * 60 < Date.now()) {
				return connection.socket.send(JSON.stringify({
					type: 'ERROR',
					payload: 'message timestamp has expired'
				}))
			}
			const valid = await ed.verify(
				Uint8Array.from(Buffer.from(signature, "hex")), 
				Uint8Array.from(Buffer.from(message, "hex")), 
				Uint8Array.from(Buffer.from(id, "hex"))
			)
			if (valid) {
				return
			}
		}
		connection.socket.send(JSON.stringify({
			type: 'ERROR',
			payload: '64 hex IDs are only allowed with valid ed25519 signatures. Use token=ed25519|<SIG>|<MSG>'
		}))
		connection.socket.close()
	}
})