Trial Period Code

[tehon3299]

I was wondering how people put trial periods on their products. Obviously it's so many days or so many uses, but how do you make the serial numbers? It's an algorithm of some sort right? Does anyone have any info on this?

 

Thanks

[philprice]

Best thing to do is just make an overly complex algorithm with a checksum, basically you say you want

 

200-20-11

 

This is a REALLY simple example, you would say the 2nd portion is the first /2 and the last is the (2nd / 2) + 1, this is a really simple one of course, you can allways convert 2 chars to ASCII if its in the correct range, you can also do maths stuff based on user name and all that kind of stuff... Pretty simple way to do it, but just a way. Better methods like SSH style "encryption" could also be used.

[be58d2003]

I am new and would kind of like to know how this is done, is there an easy way to explain this in 'plain english'?

[philprice]

with methods i guess some thing like, keyMaker.generateKey(), this could return a string of the key code by doing some alogrithm based on random numbers and your forumla, then youcould have keyMaker.checkKey(enteredKey), to check keys based on the same alogrithm but decoding not encoding... I cant really say what to do because that would defeat the point of have a specific key for your program.

[be58d2003]

Thanks, explains it a bit... There are some many different 'codes' in this thing it isn't funny... Like I said I am new to it, so I guess it means a lot of exploring and trial & error. Thanks again.

[Heiko]

It depends of course on the selling price of your product, but I think the effort you put into encrypting / key - validation algorithms should be in a good relation to the overall program complexity.

[philprice]

hmm how do you mean "so many differnet codes" you make classes and methods to check any code based on rules, not each one, one by one. You look at the layout and format of the code given, then try and parse it to see if its correct.