diff --git a/csharp/src/Google.Protobuf/ObjectIntPair.cs b/csharp/src/Google.Protobuf/ObjectIntPair.cs
index 3270b49b70..208c717d66 100644
--- a/csharp/src/Google.Protobuf/ObjectIntPair.cs
+++ b/csharp/src/Google.Protobuf/ObjectIntPair.cs
@@ -1,3 +1,35 @@
+#region Copyright notice and license
+// Protocol Buffers - Google's data interchange format
+// Copyright 2015 Google Inc.  All rights reserved.
+// https://developers.google.com/protocol-buffers/
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+#endregion
+
 using System;
 
 namespace Google.Protobuf
diff --git a/csharp/src/Google.Protobuf/Properties/AssemblyInfo.cs b/csharp/src/Google.Protobuf/Properties/AssemblyInfo.cs
index ae885f8c00..6d6ec89b04 100644
--- a/csharp/src/Google.Protobuf/Properties/AssemblyInfo.cs
+++ b/csharp/src/Google.Protobuf/Properties/AssemblyInfo.cs
@@ -41,9 +41,13 @@ using System.Security;
 [assembly: AllowPartiallyTrustedCallers]
 #endif
 
+#if SIGNING_DISABLED
+[assembly: InternalsVisibleTo("Google.Protobuf.Test")]
+#else
 [assembly: InternalsVisibleTo("Google.Protobuf.Test, PublicKey=" +
     "002400000480000094000000060200000024000052534131000400000100010025800fbcfc63a1" +
     "7c66b303aae80b03a6beaa176bb6bef883be436f2a1579edd80ce23edf151a1f4ced97af83abcd" +
     "981207041fd5b2da3b498346fcfcd94910d52f25537c4a43ce3fbe17dc7d43e6cbdb4d8f1242dc" +
     "b6bd9b5906be74da8daa7d7280f97130f318a16c07baf118839b156299a48522f9fae2371c9665" +
     "c5ae9cb6")]
+#endif
\ No newline at end of file