You may need the public key token of an assembly when you create the application configuration file. Use the strong naming tool with the -T option to extract the public key. Be sure to type the option in uppercase.
sn -T yourassembly.dll
The output will be like the following:
Microsoft (R) .NET Framework Strong Name Utility Version 4.0.30319.33440
Copyright (c) Microsoft Corporation. All rights reserved.
Public key token is 03c4e6ed81288e59