How do I Create a Serial Key system?

Hi all,

I am looking to create a system by which on the first load of a game the user will be prompted the enter a serial key.

I am aware of the basic principles of a serial key (Creating a code which is deciphered to equal a certain sum) however im not sure how to make the serial key prompt only appear on first launch.

Any help greatly appreciated,

Thanks

You'll need to save some information to local storage, and load/check to see if that value is there on start of layout. https://www.scirra.com/manual/188/local-storage

Should have thought of this myself.

Thanks for the advice.