diff --git a/websocket-sharp/Net/SslConfiguration.cs b/websocket-sharp/Net/SslConfiguration.cs
deleted file mode 100644
index bfd3e5ac..00000000
--- a/websocket-sharp/Net/SslConfiguration.cs
+++ /dev/null
@@ -1,172 +0,0 @@
-#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 08767954..0860c031 100644
--- a/websocket-sharp/websocket-sharp.csproj
+++ b/websocket-sharp/websocket-sharp.csproj
@@ -135,7 +135,6 @@
     <Compile Include="Net\HttpListenerPrefix.cs" />
     <Compile Include="Net\ClientSslConfiguration.cs" />
     <Compile Include="Net\ServerSslConfiguration.cs" />
-    <Compile Include="Net\SslConfiguration.cs" />
     <Compile Include="Net\HttpListenerAsyncResult.cs" />
     <Compile Include="Net\HttpRequestHeader.cs" />
     <Compile Include="Net\HttpResponseHeader.cs" />