Activation Key Protection: How this option works

This feature allows to "bind" application to specific PC. We are using Computer Name to bind the file.
Activation Key protection requres pair Computer Name + Product Key.
Computer Name identifies PC where file is opened.
Product Key identifies product. You can create unlimited number of products on your PC.
When file is opened it immediately asks for Activation Key. Why immediately? It should determine working period of this file. Every Activation Key you send to customers has working period (expiration date). For example - you give 1 month to your customer for evaluation. In this case you send a key to your customer with 30-days working period.
When Key is entered spreadsheet processes it and continues opening, or closes is key is invalid or expired.
This allows you to sell time limited subscriptions. For example annual subscriptions.