diff --git a/agent-cs/AgentWorker.cs b/agent-cs/AgentWorker.cs
index 9a4149f..80bc9ab 100644
--- a/agent-cs/AgentWorker.cs
+++ b/agent-cs/AgentWorker.cs
@@ -6,7 +6,7 @@ namespace ITNexusAgent;
 
 public class AgentWorker
 {
-    private const string Version = "2.8.0";
+    private const string Version = "2.9.0";
     private const string DataDir = @"C:\ProgramData\IT Nexus Agent";
     private const string ConfigPath = @"C:\ProgramData\IT Nexus Agent\config.json";
     private const string StatusPath = @"C:\ProgramData\IT Nexus Agent\status.json";
@@ -44,10 +44,11 @@ public class AgentWorker
         // Idempotent (Server liefert bestehenden Key erneut) — daher bei jedem Start sicher aufrufbar.
         var hostname = SystemInfoService.GetHostname();
         var enrolledKey = await _api.EnrollAsync(hostname);
-        if (!string.IsNullOrEmpty(enrolledKey) && enrolledKey != _config.AgentKey)
+        var configWasUnencrypted = !File.ReadAllText(ConfigPath).Contains("dpapi:");
+        if (!string.IsNullOrEmpty(enrolledKey) && (enrolledKey != _config.AgentKey || configWasUnencrypted))
         {
             _config.AgentKey = enrolledKey;
-            _config.Save(ConfigPath);
+            _config.Save(ConfigPath); // schreibt agent_key jetzt DPAPI-verschlüsselt statt im Klartext
             _api.UpdateKey(enrolledKey);
             Log("ENROLL: Per-Device-Key erhalten und gespeichert");
         }
diff --git a/agent-cs/IT-Nexus-Agent.csproj b/agent-cs/IT-Nexus-Agent.csproj
index c19d560..53e3981 100644
--- a/agent-cs/IT-Nexus-Agent.csproj
+++ b/agent-cs/IT-Nexus-Agent.csproj
@@ -7,8 +7,8 @@
     <UseWindowsForms>true</UseWindowsForms>
     <AssemblyName>IT-Nexus-Agent</AssemblyName>
     <RootNamespace>ITNexusAgent</RootNamespace>
-    <Version>2.8.0</Version>
-    <AssemblyVersion>2.8.0.0</AssemblyVersion>
+    <Version>2.9.0</Version>
+    <AssemblyVersion>2.9.0.0</AssemblyVersion>
     <Nullable>enable</Nullable>
     <ImplicitUsings>enable</ImplicitUsings>
     <AllowUnsafeBlocks>false</AllowUnsafeBlocks>
@@ -31,6 +31,7 @@
     <PackageReference Include="System.Drawing.Common" Version="8.0.0" />
     <PackageReference Include="System.Management" Version="8.0.0" />
     <PackageReference Include="System.ServiceProcess.ServiceController" Version="8.0.0" />
+    <PackageReference Include="System.Security.Cryptography.ProtectedData" Version="8.0.0" />
   </ItemGroup>
 
 </Project>
diff --git a/agent-cs/Models/Config.cs b/agent-cs/Models/Config.cs
index a148509..a13282c 100644
--- a/agent-cs/Models/Config.cs
+++ b/agent-cs/Models/Config.cs
@@ -1,25 +1,69 @@
 using Newtonsoft.Json;
 using System.IO;
+using System.Security.Cryptography;
+using System.Text;
 
 namespace ITNexusAgent.Models;
 
 public class AgentConfig
 {
-    [JsonProperty("server_url")]
+    private const string ProtectedPrefix = "dpapi:";
+
+    [JsonIgnore]
     public string ServerUrl { get; set; } = "";
 
-    [JsonProperty("agent_key")]
+    // Im Speicher immer Klartext — nur auf der Platte (config.json) liegt der verschlüsselte Wert.
+    [JsonIgnore]
     public string AgentKey { get; set; } = "";
 
+    private class RawConfig
+    {
+        [JsonProperty("server_url")] public string ServerUrl { get; set; } = "";
+        [JsonProperty("agent_key")] public string AgentKey { get; set; } = "";
+    }
+
     public static AgentConfig Load(string path)
     {
         var json = File.ReadAllText(path);
-        return JsonConvert.DeserializeObject<AgentConfig>(json)
+        var raw = JsonConvert.DeserializeObject<RawConfig>(json)
             ?? throw new Exception("Ungültige config.json");
+
+        return new AgentConfig
+        {
+            ServerUrl = raw.ServerUrl,
+            AgentKey = Unprotect(raw.AgentKey),
+        };
     }
 
+    // Verschlüsselt den Key per Windows DPAPI (LocalMachine-Scope) bevor er auf die Platte geschrieben
+    // wird — ein Klartext-Auslesen von config.json bringt einem Angreifer dann nichts mehr, da der Wert
+    // nur vom SYSTEM-Konto auf genau diesem Rechner wieder entschlüsselt werden kann.
     public void Save(string path)
     {
-        File.WriteAllText(path, JsonConvert.SerializeObject(this, Formatting.Indented));
+        var raw = new RawConfig { ServerUrl = ServerUrl, AgentKey = Protect(AgentKey) };
+        File.WriteAllText(path, JsonConvert.SerializeObject(raw, Formatting.Indented));
+    }
+
+    private static string Protect(string plaintext)
+    {
+        if (string.IsNullOrEmpty(plaintext)) return plaintext;
+        var bytes = ProtectedData.Protect(Encoding.UTF8.GetBytes(plaintext), null, DataProtectionScope.LocalMachine);
+        return ProtectedPrefix + Convert.ToBase64String(bytes);
+    }
+
+    // Erkennt das alte Klartext-Format (z.B. frisch aus dem Installer-Template) und lässt es unverändert
+    // durch — wird beim nächsten Save() automatisch verschlüsselt persistiert.
+    private static string Unprotect(string stored)
+    {
+        if (string.IsNullOrEmpty(stored) || !stored.StartsWith(ProtectedPrefix)) return stored;
+        try
+        {
+            var bytes = ProtectedData.Unprotect(Convert.FromBase64String(stored[ProtectedPrefix.Length..]), null, DataProtectionScope.LocalMachine);
+            return Encoding.UTF8.GetString(bytes);
+        }
+        catch
+        {
+            return stored; // Korrupt/falsche Maschine → unverändert zurückgeben statt Crash
+        }
     }
 }
diff --git a/agent-cs/setup.iss b/agent-cs/setup.iss
index ff2fbe0..db406c7 100644
--- a/agent-cs/setup.iss
+++ b/agent-cs/setup.iss
@@ -1,5 +1,5 @@
 #define MyAppName "IT Nexus Agent"
-#define MyAppVersion "2.8.0"
+#define MyAppVersion "2.9.0"
 #define MyAppPublisher "Cereda Systems GmbH"
 #define MyAppURL "https://it-nexus.cereda-systems.de"
 #define MyAppExeName "IT-Nexus-Agent.exe"
diff --git a/frontend/src/pages/PatchManagementPage.jsx b/frontend/src/pages/PatchManagementPage.jsx
index 6627acf..87bb778 100644
--- a/frontend/src/pages/PatchManagementPage.jsx
+++ b/frontend/src/pages/PatchManagementPage.jsx
@@ -5,7 +5,7 @@ import { useAuth } from '../context/AuthContext';
 
 const ANN_TYPES = { maintenance: { icon: '🔧', label: 'Wartung', color: '#f59e0b' }, warning: { icon: '⚠️', label: 'Warnung', color: '#ef4444' }, info: { icon: 'ℹ️', label: 'Info', color: '#6366f1' } };
 
-const LATEST_AGENT_VERSION = '2.8.0';
+const LATEST_AGENT_VERSION = '2.9.0';
 const SEVERITY_LABELS = { critical: 'Kritisch', important: 'Wichtig', moderate: 'Moderat', low: 'Niedrig', all: 'Alle' };
 const SEVERITY_COLORS = { critical: '#EF4444', important: '#F59E0B', moderate: '#3B82F6', low: '#6B7280', all: '#0D9488' };
 const COMMAND_LABELS = { check_updates: '🔍 Update-Scan', install_updates: '⬇️ Installation', reboot: '🔄 Neustart', upgrade_win11: '🪟 Win 11 Upgrade', update_agent: '⬆️ Agent-Update' };