diff --git a/src/app.js b/src/app.js
index 6926c62..97513d0 100644
--- a/src/app.js
+++ b/src/app.js
@@ -52,10 +52,9 @@ io.on('connection', async (socket) => {
         console.log('User disconnected');
     });
     socket.on('chat message', async (msg, room, tag, iv, nonce) => {
-        const roomid = room.substring(5);
-        const members = await database.getRoomMembers(roomid);
+        const members = await database.getRoomMembers(room);
         members.forEach(memberRoom => {
-            socket.to(memberRoom).emit('chat message', msg, roomid, tag, iv, nonce, session.publicKey);
+            socket.to(memberRoom).emit('chat message', msg, room, tag, iv, nonce, session.publicKey);
         });
         console.log('message: ' + msg + ', sender: ' + session.id);
         console.log(session.publicKey);
diff --git a/src/public/arrayutils.js b/src/public/arrayutils.js
index 574e18c..9452144 100644
--- a/src/public/arrayutils.js
+++ b/src/public/arrayutils.js
@@ -19,4 +19,37 @@ function splitIntoChunks(data) {
     return chunks;
 }
 
-export { concatUint8Arrays, splitIntoChunks };
+/*
+Convert  an ArrayBuffer into a string
+from https://developers.google.com/web/updates/2012/06/How-to-convert-ArrayBuffer-to-and-from-String
+*/
+function ab2str(buf) {
+    return String.fromCharCode.apply(null, new Uint8Array(buf));
+}
+
+/*
+Convert a string into an ArrayBuffer
+from https://developers.google.com/web/updates/2012/06/How-to-convert-ArrayBuffer-to-and-from-String
+*/
+function str2ab(str) {
+    const buf = new ArrayBuffer(str.length);
+    const bufView = new Uint8Array(buf);
+    for (let i = 0, strLen = str.length; i < strLen; i++) {
+        bufView[i] = str.charCodeAt(i);
+    }
+    return buf;
+}
+
+function generateRandomUint8Array(length = 16) {
+    const randomArray = new Uint8Array(length);
+    window.crypto.getRandomValues(randomArray);
+    return randomArray;
+}
+
+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'), '');
+
+export { concatUint8Arrays, splitIntoChunks, ab2str, str2ab, fromHexString, toHexString, generateRandomUint8Array };
diff --git a/src/public/chat.js b/src/public/chat.js
index 26bf244..73ad527 100644
--- a/src/public/chat.js
+++ b/src/public/chat.js
@@ -2,6 +2,7 @@ import { genKeys, sharedKey } from "./ecdh.js";
 import { keccakAEAD } from "./aead.js";
 import { keccakKDF } from "./kdf.js";
 import { render_room, render_rooms_wrapper } from "./rooms.js";
+import { fromHexString, toHexString, generateRandomUint8Array } from "./arrayutils.js";
 
 const socket = io();
 let secret = null;
@@ -9,13 +10,15 @@ let sharedsecret = {};
 let dh_ratchets = {};
 let sending_ratchets = {};
 let receiving_ratchets = {};
+let messages_exchanged = {};
+const max_messages_number = 5;
 
 render_rooms_wrapper();
 
 function init_ratchets(order, user_pubkey) {
     let dh_ratchet = new keccakKDF()
     let key_1 =  dh_ratchet.init(sharedsecret[user_pubkey], new Uint8Array(0));
-    let key_2 = dh_ratchet.next(new Uint8Array(0));
+    let key_2 = dh_ratchet.next();
     dh_ratchets[user_pubkey] = dh_ratchet;
     let sending_ratchet = new keccakKDF();
     let receiving_ratchet = new keccakKDF();
@@ -31,7 +34,7 @@ function init_ratchets(order, user_pubkey) {
     }
     sending_ratchets[user_pubkey] = sending_ratchet;
     receiving_ratchets[user_pubkey] = receiving_ratchet;
-
+    messages_exchanged[user_pubkey] = 0;
 }
 
 socket.on('chat message', (msg, room, tag_received, iv, nonce, pubkey_received) => {
@@ -55,6 +58,10 @@ socket.on('chat message', (msg, room, tag_received, iv, nonce, pubkey_received)
 });
 
 socket.on('key exchange', (user_pubkey, pubkey, part) => {
+    key_exchange(user_pubkey, pubkey, part);
+});
+
+function key_exchange(user_pubkey, pubkey, part) {
     let keys = null;
     switch (part) {
         case 0:
@@ -76,7 +83,14 @@ socket.on('key exchange', (user_pubkey, pubkey, part) => {
             init_ratchets(1, user_pubkey);
             break;
     }
-});
+}
+
+function reset_ratchets(user_pubkey) {
+    if (messages_exchanged[user_pubkey] >= max_messages_number) {
+        key_exchange(user_pubkey, null, 0);
+        messages_exchanged[user_pubkey] = 0;
+    }
+}
 
 export function create_listener(form, input, messages) {
     form.addEventListener('submit', function(e) {
@@ -86,8 +100,10 @@ export function create_listener(form, input, messages) {
             window.scrollTo(0, document.body.scrollHeight);
             const pubkey = Array.from(form.classList).find(className => className.startsWith('key-')).replace('key-', '');
             let {cipher, tag, iv, nonce} = encrypt_message(input.value, pubkey);
-            socket.emit('chat message', cipher, form.id, tag, iv, nonce);
+            socket.emit('chat message', cipher, form.id.substring(5), tag, iv, nonce);
             input.value = '';
+            messages_exchanged[pubkey] += 1;
+            reset_ratchets(pubkey);
         }
     });
 }
@@ -115,12 +131,6 @@ function decrypt_message(cipher, user_pubkey, iv, nonce, associated_data) {
             };
 }
 
-function generateRandomUint8Array(length = 16) {
-    const randomArray = new Uint8Array(length);
-    window.crypto.getRandomValues(randomArray);
-    return randomArray;
-}
-
 function append_message(type, text, messageUl) {
     const item = document.createElement('li');
     const bubble = document.createElement('div');
@@ -143,12 +153,6 @@ function append_message(type, text, messageUl) {
     messageUl.appendChild(item);
 }
 
-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'), '');
-
 export async function reconnectSocket() {
     socket.disconnect();
     console.log("Socket disconnected.");
diff --git a/src/public/ecc.js b/src/public/ecc.js
index b2bd6d6..569cfe2 100644
--- a/src/public/ecc.js
+++ b/src/public/ecc.js
@@ -1,23 +1,4 @@
-/*
-Convert  an ArrayBuffer into a string
-from https://developers.google.com/web/updates/2012/06/How-to-convert-ArrayBuffer-to-and-from-String
-*/
-export function ab2str(buf) {
-    return String.fromCharCode.apply(null, new Uint8Array(buf));
-}
-
-/*
-Convert a string into an ArrayBuffer
-from https://developers.google.com/web/updates/2012/06/How-to-convert-ArrayBuffer-to-and-from-String
-*/
-export function str2ab(str) {
-    const buf = new ArrayBuffer(str.length);
-    const bufView = new Uint8Array(buf);
-    for (let i = 0, strLen = str.length; i < strLen; i++) {
-        bufView[i] = str.charCodeAt(i);
-    }
-    return buf;
-}
+import {ab2str, str2ab} from './arrayutils.js';
 
 export function exportedKeyToPem(key, type) {
     let exportedAsString = ab2str(key);
diff --git a/src/public/register.js b/src/public/register.js
index 9c49de2..bb75dfa 100644
--- a/src/public/register.js
+++ b/src/public/register.js
@@ -1,5 +1,5 @@
-
-import { ab2str, exportedKeyToPem, pemToKey, genKey } from "./ecc.js";
+import { exportedKeyToPem, pemToKey, genKey } from "./ecc.js";
+import { ab2str } from "./arrayutils.js"
 import { add_div_register_text } from "./registertext.js";
 
 export async function registerConfirm() {
diff --git a/src/views/index.pug b/src/views/index.pug
index 928fcd1..84e1ab1 100644
--- a/src/views/index.pug
+++ b/src/views/index.pug
@@ -7,17 +7,12 @@ html(lang="en-US")
     link(rel="stylesheet" href="/style.css")
     script(src="/socket.io/socket.io.js", defer)
     script(src="/script.js", defer)
-    script(type="module", src="/ecc.js", defer)
     if isLoggedIn
-      script(type="module", src="/chat.js", defer)
-      script(src="/pubkey.js", defer)
       script(src="/noble-curves.js", defer)
-      script(type="module", src="/rooms.js", defer)
-      script(type="module", src="/ecdh.js", defer)
+      script(src="/pubkey.js", defer)
       script(type="module", src="/popups-logged.js", defer)
-      script(type="module", src="/keccak.js", defer)
-      script(type="module", src="/aead.js", defer)
-      script(type="module", src="/kdf.js", defer)
+      script(type="module", src="/rooms.js", defer)
+      script(type="module", src="/chat.js", defer)
     else
        script(type="module", src="/popups.js", defer)
        script(type="module", src="/register.js", defer)
diff --git a/tests/ecc.test.js b/tests/ecc.test.js
index 7072dc4..c69951b 100644
--- a/tests/ecc.test.js
+++ b/tests/ecc.test.js
@@ -1,4 +1,5 @@
-import { ab2str, str2ab, exportedKeyToPem, pemToKey, genKey } from '../src/public/ecc.js';
+import { exportedKeyToPem, pemToKey, genKey } from '../src/public/ecc.js';
+import { ab2str, str2ab } from '../src/public/arrayutils.js';
 
 describe('ecc.js functions', () => {