The way that I proposed it:

1) You get the game on CD or by downloading it from some website.
2) When you register the game, you get a Registration Code. If you buy the game, that registration code is on the CD sleeve or whatever
3) You are prompted, when you play the game, to enter the registration code. If the code you provide doesn't decrypt some of the game files, then the game knows that it was an invalid code.

The Private Key is never given to anyone: the programmer himself (or herself, in my case) would keep it. Then when someone registers, I would use my Private Key to generate a Public Key. This 'public key' that I send back to them is their Registration Code that unlocks the game.

It is possible that one person will try to distribute his or her Registration Code to others. As long as there's no internet connection which tells the programmer's server that the Registration Code is being used in several different locations at the same time (read: pirated), then there is really no way to tell that the Registration Code is being passed around. But as soon as someone registers, then we know that that code was used, and deal with pirates however we will.

So everyone gets a different Registration Code. Player 1 gets code Y4X7T, while Player 2's code is 55F5C, etc.

Did that help clarify, piccolo?

yes i c where your getting at. there have been many methods to crack both of those examples. as far as i c nothing cant be cracked. but that will stop me from cracking your software because it a pain to do. but if i was payed thats a different story. if a group of people that wanted to play me to crack in for there group it will be cracked on put on the internet for free downloading so in the end it make no sense. if people want to crack it it will be cracked.

[edit]
take what money you get. don't try and get every penny.

Some installers have nagscreens but they have a KEY Function where U make the codes randomizem and deal with the Nagscreens of shareware (timer)

Here is a thought I had: What if each copy of the game got a new randomly generated code every time it accessed the registration check server? Then, it would only allow the copy of the game with the correct code. Then, after each successful connection/verification with the passcode, it would get a new one. Would this work?

actually program a nagscreen... Look at Sunnny ball and Pixel ships retro.. installers may have a keygen app! these may cost 20 or more Dollars...

Or make a grabber file Password protect anything and everything

So you're saying that Victor is incorrect: you CAN'T have 1 Private Key create 1000 Public Keys?
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Well, i did not write it clearly.
Anyway, for practical purposes and for simplicity, cosider that exists just one public key and just one private key.