ECDH key exchange

src/public/chat.js

@@ -1,4 +1,37 @@
+import { genKeys, sharedKey } from "./ecdh.js";
+
 const socket = io();
+let secret = null;
+let sharedsecret = {};
+
+socket.on('chat message', (msg, room) => {
+    console.log(`received: ${msg}`);
+    console.log(sharedsecret);
+    const item = document.createElement('li');
+    item.textContent = msg;
+    const messages = document.getElementById(`messages-${room}`);
+    messages.appendChild(item);
+    window.scrollTo(0, document.body.scrollHeight);
+});
+
+socket.on('connected', (user_pubkey) => {
+    const keys = genKeys();
+    secret = keys.privkey;
+    socket.emit('key exchange', user_pubkey, toHexString(keys.pubkey));
+});
+
+socket.on('key exchange', (user_pubkey, pubkey) => {
+    const keys = genKeys();
+    secret = keys.privkey
+    sharedsecret[user_pubkey] = sharedKey(secret, fromHexString(pubkey));
+    socket.emit('key exchange 2', user_pubkey, toHexString(keys.pubkey));
+    console.log(`shared secret: ${toHexString(sharedsecret[user_pubkey])}`);
+});
+
+socket.on('key exchange 2', (user_pubkey, pubkey) => {
+    sharedsecret[user_pubkey] = sharedKey(secret, fromHexString(pubkey));
+    console.log(`shared secret: ${toHexString(sharedsecret[user_pubkey])}`);
+});
 
 export function create_listener(form, input) {
     form.addEventListener('submit', function(e) {
@@ -9,3 +42,9 @@ export function create_listener(form, input) {
         }
     });
 }
+
+const fromHexString = (hexString) =>
+  Uint8Array.from(hexString.match(/.{1,2}/g).map((byte) => parseInt(byte, 16)));
+
+const toHexString = (bytes) =>
+  bytes.reduce((str, byte) => str + byte.toString(16).padStart(2, '0'), '');