diff --git a/ClientServerLib/ClientServerLib/CClient.cs b/ClientServerLib/ClientServerLib/CClient.cs
index 41347cf3..fe8b4a58 100644
--- a/ClientServerLib/ClientServerLib/CClient.cs
+++ b/ClientServerLib/ClientServerLib/CClient.cs
@@ -33,12 +33,6 @@ namespace ClientServerLib
             get { return connected; }
         }
 
-        public bool LoggedIn
-        {
-            get { return connection.LoggedIn; }
-            set { connection.LoggedIn = value; }
-        }
-
         public CClient()
         {
             doConnect = false;
diff --git a/ClientServerLib/ClientServerLib/CConnection.cs b/ClientServerLib/ClientServerLib/CConnection.cs
index 50aa3460..900a4366 100644
--- a/ClientServerLib/ClientServerLib/CConnection.cs
+++ b/ClientServerLib/ClientServerLib/CConnection.cs
@@ -18,7 +18,6 @@ namespace ClientServerLib
         private int connectionID;
 
         public TcpClient TcpClient;
-        public bool LoggedIn;
 
         public bool KeySet
         {
@@ -34,7 +33,6 @@ namespace ClientServerLib
         {
             TcpClient = client;
             keySet = false;
-            LoggedIn = false;
             connectionID = ConnectionID;
             encoder = new UTF8Encoding();
         }
diff --git a/ClientServerLib/ClientServerLib/CServer.cs b/ClientServerLib/ClientServerLib/CServer.cs
index 24e54557..37f44139 100644
--- a/ClientServerLib/ClientServerLib/CServer.cs
+++ b/ClientServerLib/ClientServerLib/CServer.cs
@@ -73,28 +73,39 @@ namespace ClientServerLib
         private void ListenForClients()
         {
             tcpListener.Start();
+            TcpClient client;
 
             while (running)
             {
                 //wait for new client
-                TcpClient client = tcpListener.AcceptTcpClient();
-
-                int id = ids.Dequeue();
-                CConnection connection = new CConnection(client, id);
-
-                lock (clients)
+                try
                 {
-                    clients.Add(id, connection);
+                    client = tcpListener.AcceptTcpClient();
+                }
+                catch
+                {
+                    client = null;
                 }
 
-                Thread clientThread = new Thread(new ParameterizedThreadStart(HandleClientCom));
+                if (client != null)
+                {
+                    int id = ids.Dequeue();
+                    CConnection connection = new CConnection(client, id);
 
-                NetworkStream clientStream = client.GetStream();
-                byte[] serverParams = connection.GetKeyParams();
-                clientStream.Write(serverParams, 0, serverParams.Length);
-                clientStream.Flush();
+                    lock (clients)
+                    {
+                        clients.Add(id, connection);
+                    }
 
-                clientThread.Start(connection);
+                    Thread clientThread = new Thread(new ParameterizedThreadStart(HandleClientCom));
+
+                    NetworkStream clientStream = client.GetStream();
+                    byte[] serverParams = connection.GetKeyParams();
+                    clientStream.Write(serverParams, 0, serverParams.Length);
+                    clientStream.Flush();
+
+                    clientThread.Start(connection);
+                }
             }
         }
 
diff --git a/ClientServerLib/ClientServerLib/ClientServerLib.csproj b/ClientServerLib/ClientServerLib/ClientServerLib.csproj
index 90c0aa91..b9a347bb 100644
--- a/ClientServerLib/ClientServerLib/ClientServerLib.csproj
+++ b/ClientServerLib/ClientServerLib/ClientServerLib.csproj
@@ -48,6 +48,8 @@
     <Compile Include="DeffieHellman\StrongNumberProvider.cs" />
     <Compile Include="Properties\AssemblyInfo.cs" />
     <Compile Include="Structs.cs" />
+    <Compile Include="Vocaluxe\CCommands.cs" />
+    <Compile Include="Vocaluxe\VocaluxeStructs.cs" />
   </ItemGroup>
   <Import Project="$(MSBuildToolsPath)\Microsoft.CSharp.targets" />
   <!-- To modify your build process, add your task inside one of the targets below and uncomment it. 
diff --git a/ClientServerLib/ClientServerLib/Vocaluxe/CCommands.cs b/ClientServerLib/ClientServerLib/Vocaluxe/CCommands.cs
new file mode 100644
index 00000000..ef3a54b1
--- /dev/null
+++ b/ClientServerLib/ClientServerLib/Vocaluxe/CCommands.cs
@@ -0,0 +1,99 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.IO;
+using System.Runtime.Serialization.Formatters;
+using System.Runtime.Serialization.Formatters.Binary;
+using System.Text;
+using System.Security.Cryptography;
+
+
+namespace Vocaluxe.Base.Server
+{
+    public static class CCommands
+    {
+        public static SHA256Managed SHA256 = new SHA256Managed();
+
+        public const int CommandLogin = 20;
+        public const int ResponseLoginWrongPassword = 21;
+        public const int ResponseLoginFailed = 22;
+        public const int ResponseLoginOK = 23;
+
+        public static byte[] CreateCommandWithoutParams(int Command)
+        {
+            return BitConverter.GetBytes(Command);
+        }
+
+        /*
+        public static byte[] CreateResponseSendUserNames(SUsers Users)
+        {
+            return Serialize<SUsers>(ResponseSendUserNames, Users);
+        }
+
+        public static SUsers DecodeResponseSendUserNames(byte[] response)
+        {
+            SUsers users;
+            TryDeserialize<SUsers>(response, out users);
+            return users;
+        }
+        */
+
+        public static byte[] CreateCommandLogin(string Password)
+        {
+            SLoginData data = new SLoginData();
+            data.SHA256 = SHA256.ComputeHash(Encoding.UTF8.GetBytes(Password));
+
+            return Serialize<SLoginData>(CommandLogin, data);
+        }
+
+        public static bool ResponseCommandLogin(byte[] Message, out SLoginData LoginData)
+        {
+            return TryDeserialize<SLoginData>(Message, out LoginData);
+        }
+
+        private static byte[] Serialize<T>(int Command, T obj)
+        {
+            byte[] command = BitConverter.GetBytes(Command);
+
+            MemoryStream stream = new MemoryStream();
+            stream.Write(command, 0, command.Length);
+
+            byte[] data;
+            using (MemoryStream ms = new MemoryStream())
+            {
+                BinaryFormatter formatter = new BinaryFormatter();
+                formatter.Serialize(ms, obj);
+                data = ms.ToArray();
+            }
+            stream.Write(data, 0, data.Length);
+            return stream.ToArray();
+        }
+
+        private static bool TryDeserialize<T>(byte[] message, out T obj)
+        {
+            obj = default(T);
+
+            if (message == null)
+                return false;
+
+            if (message.Length < 5)
+                return false;
+
+            byte[] data = new byte[message.Length - 4];
+            Array.Copy(message, 4, data, 0, data.Length);
+            using (MemoryStream ms = new MemoryStream(data))
+            {
+                try
+                {
+                    BinaryFormatter formatter = new BinaryFormatter();
+                    obj = (T)formatter.Deserialize(ms);
+                    return true;
+                }
+                catch (Exception)
+                {
+                    return false;
+                }
+            }
+        }
+    }
+}
diff --git a/ClientServerLib/ClientServerLib/Vocaluxe/VocaluxeStructs.cs b/ClientServerLib/ClientServerLib/Vocaluxe/VocaluxeStructs.cs
new file mode 100644
index 00000000..76af669d
--- /dev/null
+++ b/ClientServerLib/ClientServerLib/Vocaluxe/VocaluxeStructs.cs
@@ -0,0 +1,10 @@
+using System;
+
+namespace Vocaluxe.Base.Server
+{
+    [Serializable]
+    public struct SLoginData
+    {
+        public byte[] SHA256;
+    }
+}
\ No newline at end of file
diff --git a/ClientServerLib/ClientTest/ClientTest.Designer.cs b/ClientServerLib/ClientTest/ClientTest.Designer.cs
index c04db48e..c1101555 100644
--- a/ClientServerLib/ClientTest/ClientTest.Designer.cs
+++ b/ClientServerLib/ClientTest/ClientTest.Designer.cs
@@ -174,7 +174,7 @@
             this.tbPassword.Name = "tbPassword";
             this.tbPassword.Size = new System.Drawing.Size(86, 20);
             this.tbPassword.TabIndex = 6;
-            this.tbPassword.Text = "vocaluxe";
+            this.tbPassword.UseSystemPasswordChar = true;
             // 
             // lbPassword
             // 
diff --git a/ClientServerLib/ClientTest/ClientTest.cs b/ClientServerLib/ClientTest/ClientTest.cs
index 3ed470ee..96444eb4 100644
--- a/ClientServerLib/ClientTest/ClientTest.cs
+++ b/ClientServerLib/ClientTest/ClientTest.cs
@@ -9,16 +9,19 @@ using System.Text;
 using System.Windows.Forms;
 
 using ClientServerLib;
+using Vocaluxe.Base.Server;
 
 namespace ClientTest
 {
     public partial class ClientTest : Form
     {
         CClient client;
+        private bool loggedIn;
 
         public ClientTest()
         {
             client = new CClient();
+            loggedIn = false;
 
             InitializeComponent();
         }
@@ -39,7 +42,10 @@ namespace ClientTest
 
         private void btLogin_Click(object sender, EventArgs e)
         {
+            if (!client.Connected)
+                return;
 
+            client.SendMessage(CCommands.CreateCommandLogin(tbPassword.Text), OnResponse);
         }
 
         private void Connect()
@@ -67,6 +73,38 @@ namespace ClientTest
             client.Disconnect();
         }
 
+        private void OnResponse(byte[] Message)
+        {
+            if (Message == null)
+                return;
+
+            if (Message.Length < 4)
+                return;
+
+            int command = BitConverter.ToInt32(Message, 0);
+            switch (command)
+            {
+                case CCommands.ResponseLoginFailed:
+                    MessageBox.Show("Unknown Error on login", "Login Failed", MessageBoxButtons.OK, MessageBoxIcon.Error);
+                    break;
+
+                case CCommands.ResponseLoginWrongPassword:
+                    MessageBox.Show("Wrong Password", "Login Failed", MessageBoxButtons.OK, MessageBoxIcon.Error);
+                    break;
+
+                case CCommands.ResponseLoginOK:
+                    loggedIn = true;
+                    this.Invoke((MethodInvoker)delegate
+                    {
+                        lbConnectionStatusText.Text = "Logged in";
+                    });
+                    break;
+
+                default:
+                    break;
+            }
+        }
+
         private void OnConnectionChanged(bool Connected)
         {
             if (Connected)
@@ -87,6 +125,7 @@ namespace ClientTest
                     btConnect.Text = "Connect";
                     btLogin.Text = "Login";
                     btLogin.Enabled = false;
+                    loggedIn = false;
                 });
             }
         }
diff --git a/Output/ClientServerLib.dll b/Output/ClientServerLib.dll
index b762cd23..a0a4cb55 100644
Binary files a/Output/ClientServerLib.dll and b/Output/ClientServerLib.dll differ
diff --git a/Vocaluxe/Base/CConfig.cs b/Vocaluxe/Base/CConfig.cs
index 73c65f55..1979c10a 100644
--- a/Vocaluxe/Base/CConfig.cs
+++ b/Vocaluxe/Base/CConfig.cs
@@ -115,6 +115,7 @@ namespace Vocaluxe.Base
         // Server
         public static EOffOn Server = EOffOn.TR_CONFIG_ON;
         public static int ServerPort = 3000;
+        public static string ServerPassword = "vocaluxe";
 
         //Lists to save parameters and values
         private static readonly List<string> _Params = new List<string>();
diff --git a/Vocaluxe/Base/Server/CClientHandler.cs b/Vocaluxe/Base/Server/CClientHandler.cs
new file mode 100644
index 00000000..7d0fdfcc
--- /dev/null
+++ b/Vocaluxe/Base/Server/CClientHandler.cs
@@ -0,0 +1,18 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+
+namespace Vocaluxe.Base.Server
+{
+    internal class CClientHandler
+    {
+        public int ConnectionID;
+        public bool LoggedIn;
+
+        public CClientHandler(int ConnectionID)
+        {
+            this.ConnectionID = ConnectionID;
+        }
+    }
+}
diff --git a/Vocaluxe/Base/Server/CVocaluxeServer.cs b/Vocaluxe/Base/Server/CVocaluxeServer.cs
index b4fd8e2a..4441801c 100644
--- a/Vocaluxe/Base/Server/CVocaluxeServer.cs
+++ b/Vocaluxe/Base/Server/CVocaluxeServer.cs
@@ -11,9 +11,11 @@ namespace Vocaluxe.Base.Server
     static class CVocaluxeServer
     {
         private static CServer _Server;
+        private static Dictionary<int, CClientHandler> _Clients;
 
         public static void Init()
         {
+            _Clients = new Dictionary<int, CClientHandler>();
             _Server = new CServer(RequestHandler, CConfig.ServerPort);
         }
 
@@ -26,11 +28,62 @@ namespace Vocaluxe.Base.Server
         public static void Close()
         {
             _Server.Stop();
+            _Clients = new Dictionary<int, CClientHandler>();
         }
 
         private static byte[] RequestHandler(int ConnectionID, byte[] Message)
         {
-            return null;
+            if (Message == null)
+                return null;
+
+            if (Message.Length < 4)
+                return null;
+
+            lock (_Clients)
+            {
+                if (!_Clients.ContainsKey(ConnectionID))
+                {
+                    CClientHandler client = new CClientHandler(ConnectionID);
+                    _Clients.Add(ConnectionID, client);
+                }
+            }
+
+            int command = BitConverter.ToInt32(Message, 0);
+            byte[] answer = null;
+
+            switch (command)
+            {
+                case CCommands.CommandLogin:
+                    SLoginData data;
+
+                    if (!CCommands.ResponseCommandLogin(Message, out data))
+                        answer = CCommands.CreateCommandWithoutParams(CCommands.ResponseLoginFailed);
+                    else
+                    {
+                        byte[] serverPW = CCommands.SHA256.ComputeHash(Encoding.UTF8.GetBytes(CConfig.ServerPassword));
+
+                        bool ok = true;
+                        for (int i = 0; i < 32; i++)
+                        {
+                            if (serverPW[i] != data.SHA256[i])
+                            {
+                                ok = false;
+                                break;
+                            }
+                        }
+
+                        if (!ok)
+                            answer = CCommands.CreateCommandWithoutParams(CCommands.ResponseLoginWrongPassword);
+                        else
+                            answer = CCommands.CreateCommandWithoutParams(CCommands.ResponseLoginOK);
+                    }
+                    break;
+
+                default:
+                    break;
+            }
+
+            return answer;
         }
     }
 }
diff --git a/Vocaluxe/Vocaluxe.csproj b/Vocaluxe/Vocaluxe.csproj
index 0c75048d..7105a451 100644
--- a/Vocaluxe/Vocaluxe.csproj
+++ b/Vocaluxe/Vocaluxe.csproj
@@ -200,6 +200,7 @@
     <Compile Include="Base\CWebcam.cs" />
     <Compile Include="Base\Font\CFonts.cs" />
     <Compile Include="Base\Font\CGlyph.cs" />
+    <Compile Include="Base\Server\CClientHandler.cs" />
     <Compile Include="Base\Server\CVocaluxeServer.cs" />
     <Compile Include="CSplashScreen.cs">
       <SubType>Form</SubType>