diff --git a/frontend/src/App.jsx b/frontend/src/App.jsx
index cc40285..c007e01 100644
--- a/frontend/src/App.jsx
+++ b/frontend/src/App.jsx
@@ -687,6 +687,34 @@ function BestellStats() {
   );
 }
 
+// ── Nachrichten-Badge ─────────────────────────────────────────────────────────
+function MessageBadge({ setActive }) {
+  const [count, setCount] = useState(0);
+  useEffect(() => {
+    const load = () => api('/nachrichten/unread-count').then(d=>setCount(d.count||0)).catch(()=>{});
+    load();
+    const t = setInterval(load, 15000);
+    return () => clearInterval(t);
+  }, []);
+  if (count === 0) return null;
+  return (
+    <div style={{...S.card,marginBottom:10,padding:'12px 14px',
+      border:'1px solid rgba(78,205,196,0.25)',background:'rgba(78,205,196,0.07)',
+      display:'flex',alignItems:'center',gap:12,cursor:'pointer'}}
+      onClick={()=>setActive('nachrichten')}>
+      <div style={{width:36,height:36,borderRadius:'50%',background:'linear-gradient(135deg,#4ecdc4,#ff6b9d)',
+        display:'flex',alignItems:'center',justifyContent:'center',fontSize:18,flexShrink:0}}>💬</div>
+      <div style={{flex:1}}>
+        <div style={{color:'#fff',fontFamily:"'Space Mono',monospace",fontSize:13,fontWeight:700}}>
+          {count} neue Nachricht{count!==1?'en':''}
+        </div>
+        <div style={{color:'rgba(78,205,196,0.7)',fontFamily:'monospace',fontSize:10,marginTop:2}}>🔒 Ende-zu-Ende verschlüsselt</div>
+      </div>
+      <div style={{color:'rgba(78,205,196,0.5)',fontSize:16}}>›</div>
+    </div>
+  );
+}
+
 function Dashboard({ toast, mobile }) {
   return (
     <div style={{ padding: mobile ? '14px 12px 90px' : '36px 44px', maxWidth:1100 }}>
@@ -697,6 +725,7 @@ function Dashboard({ toast, mobile }) {
         </p>
       </div>
       <QuickLinks toast={toast} mobile={mobile} />
+      <MessageBadge setActive={setActive}/>
       <CalendarWidget/>
       <BestellStats/>
       <TodoList   toast={toast} />
@@ -1227,7 +1256,7 @@ export default function App() {
         <main style={mainStyle}>
           {active==='dashboard' && <Dashboard toast={toast} mobile={mobile}/>}
           {active==='admin' && <AdminPanel toast={toast} mobile={mobile} user={user}/>}
-          {activeTool && <activeTool.component toast={toast} mobile={mobile}/>}
+          {activeTool && <activeTool.component toast={toast} mobile={mobile} user={user}/>}
         </main>
       </div>
       {mobile && (
diff --git a/frontend/src/crypto.js b/frontend/src/crypto.js
new file mode 100644
index 0000000..c67825a
--- /dev/null
+++ b/frontend/src/crypto.js
@@ -0,0 +1,64 @@
+// ── End-to-End Verschlüsselung (Web Crypto API) ───────────────────────────────
+// Jeder User hat ein ECDH-Schlüsselpaar. Nachrichten werden mit einem
+// gemeinsamen AES-GCM-Schlüssel verschlüsselt, der aus beiden Schlüsseln
+// abgeleitet wird. Der Server sieht nur den verschlüsselten Ciphertext.
+
+const STORE_KEY = 'dd_ec_keypair';
+
+export async function getOrCreateKeyPair() {
+  const stored = localStorage.getItem(STORE_KEY);
+  if (stored) {
+    const { pub, priv } = JSON.parse(stored);
+    const publicKey  = await crypto.subtle.importKey('jwk', pub,  { name:'ECDH', namedCurve:'P-256' }, true,  []);
+    const privateKey = await crypto.subtle.importKey('jwk', priv, { name:'ECDH', namedCurve:'P-256' }, true, ['deriveKey']);
+    return { publicKey, privateKey };
+  }
+  const pair = await crypto.subtle.generateKey({ name:'ECDH', namedCurve:'P-256' }, true, ['deriveKey']);
+  const pub  = await crypto.subtle.exportKey('jwk', pair.publicKey);
+  const priv = await crypto.subtle.exportKey('jwk', pair.privateKey);
+  localStorage.setItem(STORE_KEY, JSON.stringify({ pub, priv }));
+  return pair;
+}
+
+export async function exportPublicKey() {
+  const { publicKey } = await getOrCreateKeyPair();
+  const jwk = await crypto.subtle.exportKey('jwk', publicKey);
+  return JSON.stringify(jwk);
+}
+
+async function deriveSharedKey(myPrivateKey, theirPublicKeyJwk) {
+  const theirKey = await crypto.subtle.importKey(
+    'jwk', JSON.parse(theirPublicKeyJwk),
+    { name:'ECDH', namedCurve:'P-256' }, false, []
+  );
+  return crypto.subtle.deriveKey(
+    { name:'ECDH', public: theirKey },
+    myPrivateKey,
+    { name:'AES-GCM', length:256 }, false, ['encrypt','decrypt']
+  );
+}
+
+export async function encryptMessage(plaintext, theirPublicKeyJwk) {
+  const { privateKey } = await getOrCreateKeyPair();
+  const sharedKey = await deriveSharedKey(privateKey, theirPublicKeyJwk);
+  const iv  = crypto.getRandomValues(new Uint8Array(12));
+  const enc = new TextEncoder();
+  const ciphertext = await crypto.subtle.encrypt({ name:'AES-GCM', iv }, sharedKey, enc.encode(plaintext));
+  return {
+    encrypted_content: btoa(String.fromCharCode(...new Uint8Array(ciphertext))),
+    iv: btoa(String.fromCharCode(...iv)),
+  };
+}
+
+export async function decryptMessage(encryptedContent, ivBase64, theirPublicKeyJwk) {
+  const { privateKey } = await getOrCreateKeyPair();
+  const sharedKey = await deriveSharedKey(privateKey, theirPublicKeyJwk);
+  const ciphertext = Uint8Array.from(atob(encryptedContent), c => c.charCodeAt(0));
+  const iv         = Uint8Array.from(atob(ivBase64),         c => c.charCodeAt(0));
+  const plaintext  = await crypto.subtle.decrypt({ name:'AES-GCM', iv }, sharedKey, ciphertext);
+  return new TextDecoder().decode(plaintext);
+}
+
+export function hasLocalKeyPair() {
+  return !!localStorage.getItem(STORE_KEY);
+}
diff --git a/frontend/src/toolRegistry.js b/frontend/src/toolRegistry.js
index 328460d..272cea4 100644
--- a/frontend/src/toolRegistry.js
+++ b/frontend/src/toolRegistry.js
@@ -1,7 +1,8 @@
 import Kalkulator3D, { SavedList } from './tools/kalkulator3d.jsx';
 import Bestellungen from './tools/bestellungen.jsx';
 import Dateien from './tools/dateien.jsx';
-import { CalculatorIcon, ArchiveIcon, DatabaseIcon, AppsIcon } from './icons.jsx';
+import { CalculatorIcon, ArchiveIcon, DatabaseIcon, AppsIcon, ZapIcon } from './icons.jsx';
+import Nachrichten from './tools/nachrichten.jsx';
 
 export const TOOLS = [
   {
@@ -36,6 +37,14 @@ export const TOOLS = [
     group:     'Werkzeuge',
     component: Dateien,
   },
+  {
+    id:        'nachrichten',
+    Icon:      ZapIcon,
+    label:     'Nachrichten',
+    navLabel:  'Chat',
+    group:     'Werkzeuge',
+    component: Nachrichten,
+  },
   // Neues Tool: { id:'...', Icon:..., label:'...', navLabel:'...', group:'...', component:... },
 ];