How to protect software from system date-time changes? [closed]

Yes, it would be possible to extend the license by up to 300% but at great effort to the user. Frankly if someone is going to spend every day of a month resetting their time to one second after they quit your program before starting it again to use it longer, there is nothing you are going to do about it, and the time you take to stop them will cost you more than they ever will.

Step 1: Create trial_tracker entry in an encrypted format in a windows registry and in file.

Step 2: Assign app install timestamp ( yyyy-mm-dd-hh-mm-ss ) to trial_tracker

Whenever app starts, check if current system timestamp is greater than trial_tracker and less then expected expiry date

• If yes, update trial_tracker to current system timestamp and continue.

• If no, trial_tracker has been tampered or trial time expired. Ask user to purchase full version or exit.

Note: User can get away with this by deleting windows registry entry and encrypted file.( if he is able to find them ).In such case, further checks can be added. For example create secondary windows registry entry which checks for existence of primary registry and encrypted file.

Along with these, additional remote checks can be applied which depends on internet connection ( optional )

Reputable game development manager stated once in a conference that it's impossible to protect software for longer than a month even with internet connection - if your software is popular :-) So you can just write software that no one wants and it will be as safe as you want :-)))

If on the other side you write reasonably popular software then you couldn't care less if a small percentage of paying customers snitch some extra time - they'll renew a week latter anyway. If you really want to do short time licensing you have to put internet as a pre-requisite. It's still going to be cracked in a month if it's good for something :-) but paying customers will by and large remain paying customers with reasonably light enforcement.

If however you piss people off by doing intrusive and scary things then you'll loose paying customers and create much bigger motivation for ppl to crack it.