PPeter - The Hungarian Guru of CD's:
The CD-Cops protection system is not using electronic "fingerprint" code. The check routine only verifies the physical angle between the first and last accessible logical block on the CD. This verification is very good to identify the an original disc. The 8-digit code holds the angle information and the check routine compares this with the CD.
CD-Cops is a very good protection system, because the software developers don't need special mastering machine, they only have to add their verifying code to the main application. The angle between the first and last logical block is different for every disc written by CD-R writer, due to the Laser Calibration Area, different CD-R types, etc.
Commercial ready-made copy protections are always interesting. Here is another one, used to protect CD-ROMs. It's a nice one, timers making sure the program will crash if something takes more time than it should (as if someone would put a breakpoint somewhere and fool around), a couple of checksums to make sure no one's been changing anything in the code, and - of course - some self-modifying code decrypting itself just when it needs to be used. It even claims to be able to separate perfect CD copies from the original CD!