diff --git a/app.js b/app.js
index 5a8f4a1..c457b5b 100644
--- a/app.js
+++ b/app.js
@@ -103,7 +103,8 @@
   function updatePhases(state) {
     const map = { IDLE:'ready', STARTING:'ready', COMMITTING:'commit',
       WAITING_FOR_COMMITS:'commit', REVEALING:'reveal',
-      WAITING_FOR_REVEALS:'reveal', VERIFYING:'verify', COMPLETE:'done' };
+      WAITING_FOR_REVEALS:'reveal', VERIFYING:'verify',
+      COMPLETE:'done', ABORTED:'done' };
     const active = map[state] || 'ready';
     let doneSeen = false;
     ['ready','commit','reveal','verify','done'].forEach(p => {
@@ -141,12 +142,19 @@
       $('btn-start-protocol').hidden = true;
     };
     protocol.onerror = err => {
-      $('protocol-text').textContent = 'Fehler: ' + err;
+      $('protocol-text').textContent = err;
+      $('result-area').hidden = false;
+      $('result-text').textContent = 'Abgebrochen';
+      $('btn-start-protocol').hidden = true;
     };
 
     mesh.ondata = (peerId, msg) => {
-      if (msg.type === 'protocol_start' && protocol && protocol.state === 'IDLE') {
+      if (msg.type === 'protocol_start') {
+        if (protocol) protocol.reset();
+        $('coin-area').hidden = true;
+        $('result-area').hidden = true;
         $('btn-start-protocol').hidden = true;
+        updatePhases('IDLE');
         protocol.start();
         return;
       }
diff --git a/protocol.js b/protocol.js
index 8abf6a8..8f6baa4 100644
--- a/protocol.js
+++ b/protocol.js
@@ -7,6 +7,10 @@ class CoinFlipProtocol {
     this.reveals = new Map();
     this.result = null;
     this.totalPeers = 0;
+    this.expectedPeers = new Set();
+    this.TIMEOUT_MS = 12000;
+    this._commitTimer = null;
+    this._revealTimer = null;
 
     this.onstatechange = null;
     this.onprogress = null;
@@ -17,7 +21,8 @@ class CoinFlipProtocol {
   async start() {
     if (this.state !== 'IDLE') return;
     this.state = 'STARTING';
-    this.totalPeers = this.mesh.getCount() + 1;
+    this.expectedPeers = new Set([this.mesh.myPeerId, ...this.mesh.getPeerIds()]);
+    this.totalPeers = this.expectedPeers.size;
     this.secret = await generateSecret();
     const myCommit = await commit(this.secret);
     this.commits.set(this.mesh.myPeerId, myCommit);
@@ -26,6 +31,7 @@ class CoinFlipProtocol {
     this.mesh.broadcast({ type: 'protocol', phase: 'commit', data: bufToBase64(myCommit) });
     this.state = 'WAITING_FOR_COMMITS';
     if (this.onstatechange) this.onstatechange('WAITING_FOR_COMMITS');
+    this._startCommitTimer();
     this._checkCommits();
   }
 
@@ -49,9 +55,54 @@ class CoinFlipProtocol {
     }
   }
 
+  /* ─── Timeout ─── */
+
+  _startCommitTimer() {
+    this._clearCommitTimer();
+    this._commitTimer = setTimeout(() => {
+      if (this.commits.size >= this.totalPeers) return;
+      const missing = [...this.expectedPeers].filter(p => !this.commits.has(p));
+      this._abort(`Timeout auf Commits von: ${missing.map(p => p.slice(0, 8)).join(', ')}`);
+    }, this.TIMEOUT_MS);
+  }
+
+  _startRevealTimer() {
+    this._clearRevealTimer();
+    this._revealTimer = setTimeout(() => {
+      if (this.reveals.size >= this.totalPeers) return;
+      const missing = [...this.expectedPeers].filter(p => !this.reveals.has(p));
+      this._abort(`Timeout auf Reveals von: ${missing.map(p => p.slice(0, 8)).join(', ')}`);
+    }, this.TIMEOUT_MS);
+  }
+
+  _clearCommitTimer() {
+    if (this._commitTimer) {
+      clearTimeout(this._commitTimer);
+      this._commitTimer = null;
+    }
+  }
+
+  _clearRevealTimer() {
+    if (this._revealTimer) {
+      clearTimeout(this._revealTimer);
+      this._revealTimer = null;
+    }
+  }
+
+  _abort(reason) {
+    this._clearCommitTimer();
+    this._clearRevealTimer();
+    this.state = 'ABORTED';
+    if (this.onstatechange) this.onstatechange('ABORTED');
+    if (this.onerror) this.onerror(reason);
+  }
+
+  /* ─── Commit phase ─── */
+
   _checkCommits() {
     if (this.state !== 'WAITING_FOR_COMMITS') return;
     if (this.commits.size >= this.totalPeers) {
+      this._clearCommitTimer();
       this._allCommitsReceived();
     }
   }
@@ -64,17 +115,23 @@ class CoinFlipProtocol {
     if (this.onprogress) this.onprogress('reveal', 1, this.totalPeers);
     this.state = 'WAITING_FOR_REVEALS';
     if (this.onstatechange) this.onstatechange('WAITING_FOR_REVEALS');
+    this._startRevealTimer();
     this._checkReveals();
   }
 
+  /* ─── Reveal phase ─── */
+
   _checkReveals() {
     if (this.state !== 'WAITING_FOR_REVEALS') return;
     if (this.reveals.size >= this.totalPeers) {
+      this._clearRevealTimer();
       this._allRevealsReceived();
     }
   }
 
   async _allRevealsReceived() {
+    this._clearRevealTimer();
+
     this.state = 'VERIFYING';
     if (this.onstatechange) this.onstatechange('VERIFYING');
 
@@ -82,12 +139,12 @@ class CoinFlipProtocol {
       if (peerId === this.mesh.myPeerId) continue;
       const commitment = this.commits.get(peerId);
       if (!commitment) {
-        if (this.onerror) this.onerror(`Fehler: Kein Commit von ${peerId}`);
+        this._abort(`Fehler: Kein Commit von ${peerId.slice(0, 8)}`);
         return;
       }
       const expected = await commit(secret);
       if (!arraysEqual(expected, commitment)) {
-        if (this.onerror) this.onerror(`Betrug erkannt! ${peerId} hat gefälscht.`);
+        this._abort(`Betrug erkannt! ${peerId.slice(0, 8)} hat gefälscht.`);
         return;
       }
     }
@@ -98,12 +155,17 @@ class CoinFlipProtocol {
     if (this.oncomplete) this.oncomplete(this.result);
   }
 
+  /* ─── Reset ─── */
+
   reset() {
+    this._clearCommitTimer();
+    this._clearRevealTimer();
     this.state = 'IDLE';
     this.secret = null;
     this.commits.clear();
     this.reveals.clear();
     this.result = null;
     this.totalPeers = 0;
+    this.expectedPeers = new Set();
   }
 }