Just to add to the above post:
You can create your own key file by running the \”sn\” .NET utility with the -k option.
sn -k ABCCompany.key
Most sites use one key file per application, or perhaps even one key file for the whole company.
In other words, if they gave you a keyfile in the tutorials, or you generated a keyfile in the tutorial, you don’t have to use that file in your applications, but you would probably generate your own key file for your company – or ask around and see if they already have a key file they want you to use.