I have a question relating to protecting the code I've developed for a few
excel spreadsheets.

I've recently been sent a spreadsheet that I've found requires a licence
key to unlock further functionality. As far as I can tell, the spreadsheet
is fully functional but there is a time limit on the use of the it
unlicenced.

I presume this would require some form of encryption. Can anyone point me
in the right direction so that I can implement something similar in my
spreadsheets. And where would the key be recorded? A flat file would be
easy prey to a hacker so I presume the use of xlVeryHidden here.

Any help would be greatly appreciated.

Cheers,

Geo