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C++ Algorithm question?

Started by DevLiquidKnight Jan 12, 2003 at 2:12 PM 0 replies 200+ views

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DevLiquidKnight

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DevLiquidKnight

Jan 12, 2003 at 2:12 PM

I have been wondering this for awhile and I have searched google and have found little info on this particular area. I was wondering does anyone know how shareware works. By shareware I mean like how you buy software at the store and it has a keycode on it you enter the keycode to activate the installation of the program. I was wondering how are the keycodes made like if I wanted to go about implmenting a keycode into some software of mine. How exactly does the algorithm work or is there any sites anyone knows of that shows C/C++ source that will help me understand how exactly the keycode is checked as well as generated. Any info would be greatly appricated. Don''t click me! Killer Eagle Software

Jare

Jan 12, 2003 at 2:43 PM

The basic idea is to come up with a key structure (say, five boxes with five letters or numbers each) whose contents conform to a certain set of rules, and when the user enters the key, you check that it conforms to those rules. A simple example would be that the sum of the ASCII codes for the characters of each box is a certain number. Then, protect the code that checks the key against hacking by encrypting it or something.

The complex part is to come up with a scheme where the rules or numbers used for checking don''t make it easy to figure out a way to generate them, so that people can''t make their own key generators. The Handbook of Applied Cryptography is a good place to read about this kind of stuff (public key systems should be of interest). It is very heavyweight but so take it easy.

http://www.cacr.math.uwaterloo.ca/hac/

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http://www.iguanademos.com/Jare

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