AndyMcKenna has written a plugin for license key generator and supplied the source code. Currently the community has been piecing together updates as new versions of nop have been released. It would be nice if this functionality was included in nop since it does support digital products. This way it could be maintained between versions. Here is a link to the plugin I am referring to: https://www.nopcommerce.com/boards/t/25607/license-key-plugin.aspx.