How to sign the dll with strong name
First you create a strong name.
1. Open Solution Explorer and open Properties.
2. Click on the Signing option
3. Checked on Sign the assembly
4. Choose strong name key file, select <New...>, and enter strong name in the TextBox and click OK.
De-assemble the assembly
Use ildasm to create intermidiate language file(.il) from your dll which contains diassembled listing of dll
Re-assemble assembly using strong name
Use ilasm to create dll from .il file which is signed by .snk file
Now you dll file is signed. to verify to it run following commands.