diff --git a/websocket-sharp/Net/ClientSslConfiguration.cs b/websocket-sharp/Net/ClientSslConfiguration.cs
index 82e71b04..5344164f 100644
--- a/websocket-sharp/Net/ClientSslConfiguration.cs
+++ b/websocket-sharp/Net/ClientSslConfiguration.cs
@@ -43,16 +43,12 @@ namespace WebSocketSharp.Net
   /// <summary>
   /// Stores the parameters used to configure a <see cref="SslStream"/> instance as a client.
   /// </summary>
-  public class ClientSslConfiguration
+  public class ClientSslConfiguration : SslConfiguration
   {
     #region Private Fields
 
-    private X509CertificateCollection           _certs;
-    private LocalCertificateSelectionCallback   _certSelectionCallback;
-    private bool                                _checkCertRevocation;
-    private SslProtocols                        _enabledProtocols;
-    private string                              _host;
-    private RemoteCertificateValidationCallback _serverCertValidationCallback;
+    private X509CertificateCollection _certs;
+    private string                    _host;
 
     #endregion
 
@@ -96,34 +92,16 @@ namespace WebSocketSharp.Net
       X509CertificateCollection clientCertificates,
       SslProtocols enabledSslProtocols,
       bool checkCertificateRevocation)
+      : base (enabledSslProtocols, checkCertificateRevocation)
     {
       _host = targetHost;
       _certs = clientCertificates;
-      _enabledProtocols = enabledSslProtocols;
-      _checkCertRevocation = checkCertificateRevocation;
     }
 
     #endregion
 
     #region Public Properties
 
-    /// <summary>
-    /// Gets or sets a value indicating whether the certificate revocation list is checked
-    /// during authentication.
-    /// </summary>
-    /// <value>
-    /// <c>true</c> if the certificate revocation list is checked; otherwise, <c>false</c>.
-    /// </value>
-    public bool CheckCertificateRevocation {
-      get {
-        return _checkCertRevocation;
-      }
-
-      set {
-        _checkCertRevocation = value;
-      }
-    }
-
     /// <summary>
     /// Gets or sets the collection that contains client certificates.
     /// </summary>
@@ -153,31 +131,11 @@ namespace WebSocketSharp.Net
     /// </value>
     public LocalCertificateSelectionCallback ClientCertificateSelectionCallback {
       get {
-        return _certSelectionCallback ??
-               (_certSelectionCallback =
-                 (sender, targetHost, localCertificates, remoteCertificate, acceptableIssuers) =>
-                   null);
-      }
-
-      set {
-        _certSelectionCallback = value;
-      }
-    }
-
-    /// <summary>
-    /// Gets or sets the SSL protocols used for authentication.
-    /// </summary>
-    /// <value>
-    /// The <see cref="SslProtocols"/> enum value that represents the protocols used for
-    /// authentication.
-    /// </value>
-    public SslProtocols EnabledSslProtocols {
-      get {
-        return _enabledProtocols;
+        return CertificateSelectionCallback;
       }
 
       set {
-        _enabledProtocols = value;
+        CertificateSelectionCallback = value;
       }
     }
 
@@ -194,13 +152,11 @@ namespace WebSocketSharp.Net
     /// </value>
     public RemoteCertificateValidationCallback ServerCertificateValidationCallback {
       get {
-        return _serverCertValidationCallback ??
-               (_serverCertValidationCallback =
-                 (sender, certificate, chain, sslPolicyErrors) => true);
+        return CertificateValidationCallback;
       }
 
       set {
-        _serverCertValidationCallback = value;
+        CertificateValidationCallback = value;
       }
     }
 
@@ -223,4 +179,4 @@ namespace WebSocketSharp.Net
 
     #endregion
   }
-}
\ No newline at end of file
+}
diff --git a/websocket-sharp/Net/ServerSslConfiguration.cs b/websocket-sharp/Net/ServerSslConfiguration.cs
index f0dbb3de..3f0883af 100644
--- a/websocket-sharp/Net/ServerSslConfiguration.cs
+++ b/websocket-sharp/Net/ServerSslConfiguration.cs
@@ -43,15 +43,12 @@ namespace WebSocketSharp.Net
   /// <summary>
   /// Stores the parameters used to configure a <see cref="SslStream"/> instance as a server.
   /// </summary>
-  public class ServerSslConfiguration
+  public class ServerSslConfiguration : SslConfiguration
   {
     #region Private Fields
 
-    private X509Certificate2                    _cert;
-    private bool                                _checkCertRevocation;
-    private bool                                _clientCertRequired;
-    private RemoteCertificateValidationCallback _clientCertValidationCallback;
-    private SslProtocols                        _enabledProtocols;
+    private X509Certificate2 _cert;
+    private bool             _clientCertRequired;
 
     #endregion
 
@@ -97,34 +94,16 @@ namespace WebSocketSharp.Net
       bool clientCertificateRequired,
       SslProtocols enabledSslProtocols,
       bool checkCertificateRevocation)
+      : base (enabledSslProtocols, checkCertificateRevocation)
     {
       _cert = serverCertificate;
       _clientCertRequired = clientCertificateRequired;
-      _enabledProtocols = enabledSslProtocols;
-      _checkCertRevocation = checkCertificateRevocation;
     }
 
     #endregion
 
     #region Public Properties
 
-    /// <summary>
-    /// Gets or sets a value indicating whether the certificate revocation list is checked
-    /// during authentication.
-    /// </summary>
-    /// <value>
-    /// <c>true</c> if the certificate revocation list is checked; otherwise, <c>false</c>.
-    /// </value>
-    public bool CheckCertificateRevocation {
-      get {
-        return _checkCertRevocation;
-      }
-
-      set {
-        _checkCertRevocation = value;
-      }
-    }
-
     /// <summary>
     /// Gets or sets a value indicating whether the client must supply a certificate for
     /// authentication.
@@ -155,30 +134,11 @@ namespace WebSocketSharp.Net
     /// </value>
     public RemoteCertificateValidationCallback ClientCertificateValidationCallback {
       get {
-        return _clientCertValidationCallback ??
-               (_clientCertValidationCallback =
-                 (sender, certificate, chain, sslPolicyErrors) => true);
-      }
-
-      set {
-        _clientCertValidationCallback = value;
-      }
-    }
-
-    /// <summary>
-    /// Gets or sets the SSL protocols used for authentication.
-    /// </summary>
-    /// <value>
-    /// The <see cref="SslProtocols"/> enum value that represents the protocols used for
-    /// authentication.
-    /// </value>
-    public SslProtocols EnabledSslProtocols {
-      get {
-        return _enabledProtocols;
+        return CertificateValidationCallback;
       }
 
       set {
-        _enabledProtocols = value;
+        CertificateValidationCallback = value;
       }
     }
 
@@ -201,4 +161,4 @@ namespace WebSocketSharp.Net
 
     #endregion
   }
-}
\ No newline at end of file
+}
diff --git a/websocket-sharp/Net/SslConfiguration.cs b/websocket-sharp/Net/SslConfiguration.cs
new file mode 100644
index 00000000..bfd3e5ac
--- /dev/null
+++ b/websocket-sharp/Net/SslConfiguration.cs
@@ -0,0 +1,172 @@
+#region License
+/*
+ * SslConfiguration.cs
+ *
+ * This code is derived from ClientSslConfiguration.cs.
+ *
+ * The MIT License
+ *
+ * Copyright (c) 2014 liryna
+ * Copyright (c) 2014 sta.blockhead
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+#endregion
+
+#region Authors
+/*
+ * Authors:
+ * - Liryna <liryna.stark@gmail.com>
+ */
+#endregion
+
+using System.Net.Security;
+using System.Security.Authentication;
+
+namespace WebSocketSharp.Net
+{
+  /// <summary>
+  /// Stores the parameters used to configure a <see cref="SslStream"/> instance.
+  /// </summary>
+  /// <remarks>
+  /// The SslConfiguration class is an abstract class.
+  /// </remarks>
+  public abstract class SslConfiguration
+  {
+    #region Private Fields
+
+    private LocalCertificateSelectionCallback   _certSelectionCallback;
+    private RemoteCertificateValidationCallback _certValidationCallback;
+    private bool                                _checkCertRevocation;
+    private SslProtocols                        _enabledProtocols;
+
+    #endregion
+
+    #region Protected Constructors
+
+    /// <summary>
+    /// Initializes a new instance of the <see cref="SslConfiguration"/> class with
+    /// the specified <paramref name="enabledSslProtocols"/> and
+    /// <paramref name="checkCertificateRevocation"/>.
+    /// </summary>
+    /// <param name="enabledSslProtocols">
+    /// The <see cref="SslProtocols"/> enum value that represents the protocols used for
+    /// authentication.
+    /// </param>
+    /// <param name="checkCertificateRevocation">
+    /// <c>true</c> if the certificate revocation list is checked during authentication;
+    /// otherwise, <c>false</c>.
+    /// </param>
+    protected SslConfiguration (SslProtocols enabledSslProtocols, bool checkCertificateRevocation)
+    {
+      _enabledProtocols = enabledSslProtocols;
+      _checkCertRevocation = checkCertificateRevocation;
+    }
+
+    #endregion
+
+    #region Protected Properties
+
+    /// <summary>
+    /// Gets or sets the callback used to select a certificate to supply to the remote party.
+    /// </summary>
+    /// <remarks>
+    /// If this callback returns <see langword="null"/>, no certificate will be supplied.
+    /// </remarks>
+    /// <value>
+    /// A <see cref="LocalCertificateSelectionCallback"/> delegate that references the method
+    /// used to select a certificate. The default value is a function that only returns
+    /// <see langword="null"/>.
+    /// </value>
+    protected LocalCertificateSelectionCallback CertificateSelectionCallback {
+      get {
+        return _certSelectionCallback ??
+               (_certSelectionCallback =
+                 (sender, targetHost, localCertificates, remoteCertificate, acceptableIssuers) =>
+                   null);
+      }
+
+      set {
+        _certSelectionCallback = value;
+      }
+    }
+
+    /// <summary>
+    /// Gets or sets the callback used to validate the certificate supplied by the remote party.
+    /// </summary>
+    /// <remarks>
+    /// If this callback returns <c>true</c>, the certificate will be valid.
+    /// </remarks>
+    /// <value>
+    /// A <see cref="RemoteCertificateValidationCallback"/> delegate that references the method
+    /// used to validate the certificate. The default value is a function that only returns
+    /// <c>true</c>.
+    /// </value>
+    protected RemoteCertificateValidationCallback CertificateValidationCallback {
+      get {
+        return _certValidationCallback ??
+               (_certValidationCallback = (sender, certificate, chain, sslPolicyErrors) => true);
+      }
+
+      set {
+        _certValidationCallback = value;
+      }
+    }
+
+    #endregion
+
+    #region Public Properties
+
+    /// <summary>
+    /// Gets or sets a value indicating whether the certificate revocation list is checked
+    /// during authentication.
+    /// </summary>
+    /// <value>
+    /// <c>true</c> if the certificate revocation list is checked; otherwise, <c>false</c>.
+    /// </value>
+    public bool CheckCertificateRevocation {
+      get {
+        return _checkCertRevocation;
+      }
+
+      set {
+        _checkCertRevocation = value;
+      }
+    }
+
+    /// <summary>
+    /// Gets or sets the SSL protocols used for authentication.
+    /// </summary>
+    /// <value>
+    /// The <see cref="SslProtocols"/> enum value that represents the protocols used for
+    /// authentication.
+    /// </value>
+    public SslProtocols EnabledSslProtocols {
+      get {
+        return _enabledProtocols;
+      }
+
+      set {
+        _enabledProtocols = value;
+      }
+    }
+
+    #endregion
+  }
+}
diff --git a/websocket-sharp/websocket-sharp.csproj b/websocket-sharp/websocket-sharp.csproj
index 620786c5..e581fbff 100644
--- a/websocket-sharp/websocket-sharp.csproj
+++ b/websocket-sharp/websocket-sharp.csproj
@@ -136,6 +136,7 @@
     <Compile Include="Net\HttpListenerPrefix.cs" />
     <Compile Include="Net\ClientSslConfiguration.cs" />
     <Compile Include="Net\ServerSslConfiguration.cs" />
+    <Compile Include="Net\SslConfiguration.cs" />
   </ItemGroup>
   <Import Project="$(MSBuildBinPath)\Microsoft.CSharp.targets" />
   <ItemGroup>