# Check for expiry in Shareware applications? **URL:** \ **Category:** Ruby\ **Created:** [March 26, 2006, 4:42pm UTC](https://www.ruby-forum.com/t/check-for-expiry-in-shareware-applications/87286 "2006-03-26T16:42:20Z")\ **Posts on this page:** 3\ **Page:** 1
**Author:** ![unknown](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/u/4bbf92/32.png) [@unknown](https://www.ruby-forum.com/u/unknown)\ **Post date:** [March 26, 2006, 4:42pm UTC](https://www.ruby-forum.com/t/check-for-expiry-in-shareware-applications/87286/1 "2006-03-26T16:42:20Z")
Dear all, sometimes software that is not released as open source comes as shareware or demo, which has limited time functionality. How can this be achieved in Ruby in some way that it cannot be trivially circumvented (i.e., do not allow for changes in system date to obtain another 30 days) ? Thank you very much! Best regards, Axel ---
**Author:** ![unknown](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/u/4bbf92/32.png) [@unknown](https://www.ruby-forum.com/u/unknown)\ **Post date:** [March 26, 2006, 4:54pm UTC](https://www.ruby-forum.com/t/check-for-expiry-in-shareware-applications/87286/2 "2006-03-26T16:54:44Z")
Hey Axel, Well, haven’t given that much of thought, but how about checking the date from the internet? The problem being that you have to be connected, but if that fails you could still try the following: save the dates of execution of the program, if the date of the computer moves before that time you know that something is going wrong - usually the user will only change the date, not the time, so you could try to just add another day when the time is not within the last day (or something like that) or, even more simple - restrict how often the program can be run. However, no matter what you do, there is no way to take the right from the user to peek into the code and figure out what’s going on. In case you save the dates in some external file, i’m quite sure that after deletion he will have full charge again 🙂 another good attempt i’ve seen was from komodo, they have a quite decent system of giving licences to use the program for a given time-span for one given machine… well, i was not too excited about komodo and prefer vim, so i didn’t give it a second look 😑 ```auto ``` ---
**Author:** ![unknown](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/u/4bbf92/32.png) [@unknown](https://www.ruby-forum.com/u/unknown)\ **Post date:** [March 26, 2006, 11:05pm UTC](https://www.ruby-forum.com/t/check-for-expiry-in-shareware-applications/87286/3 "2006-03-26T23:05:37Z")
On 3/26/06, removed\_email\_address@domain.invalid [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote: > Dear all, > > sometimes software that is not released as open source comes as shareware or > demo, which has limited time functionality. > How can this be achieved in Ruby in some way that it cannot be trivially > circumvented (i.e., do not allow for changes in system date to obtain another > 30 days) ? to secure the source code from the users i compiled the ruby code as gzipped C-string into an executable. the executable starts the ruby interpreter and evaluates the inflated script with rb\_eval (actually similar function of the ruby c api which i don’t recall now). to make it even more secure you could encrypt the gzipped string. also you could check a crc of the exe to see wether it has been modified. but with a debugger the code might be uncovered at runtime maybe. the question is, where do you store the license info (date installed / numer of times launched) so that the user cannot cirumvent it by reinstalling the product / deleting that data. – henon