Signing Assemblies
You can sign an assembly in two different, but complementary ways: with a strong name or using the File Signing Tool (Signcode.exe). Signing an assembly with a strong name adds a public key encryption to the file containing the assembly manifest. Strong name signing ensures name uniqueness, prevents name spoofing and provides callers with some identity when a reference is resolved.
To sign an assembly with a strong name :
Use the Strong Name Tool (Sn.exe) to generate a key file containing a key pair.
Add strong name attributes to the AssemblyInfo file created automatically with .NET projects. You can edit this file by double clicking its name in the Solution Explorer.
The following example uses delay signing to create a strong-named assembly with a public key file called myKey.snk.
<Assembly: AssemblyKeyFile("myKey.snk")>
<Assembly: AssemblyDelaySign(True)>
Note Assembly-level attributes are ignored if you are not creating an assembly, such as when compiling from the command line using the /target:module option.
http://support.microsoft.com/default.aspx?scid=kb;en-us;815808
http://msdn.microsoft.com/library/default.asp?url=/library/en-us/cpguide/html/cpconinstallingassemblyintoglobalassemblycache.asp
http://msdn.microsoft.com/library/default.asp?url=/library/en-us/cpguide/html/cpconglobalassemblycache.asp
http://msdn.microsoft.com/library/default.asp?url=/library/en-us/cptools/html/cpgrfglobalassemblycacheutilitygacutilexe.asp