system
Given the following post, respond as if you're commenting on Reddit:
human
How does a keygen generator actually come up with a valid registration key?
gpt
The CD key must match some pattern in order to be recognized as valid by the application, like "*every odd character must be a letter, while every even character must be a number, e.g. A1B2C3...*" as a very simple example. The keygen produces random keys that follow that pattern, after the developer has managed to find out what the pattern is through reverse engineering of the application.