This reminds me of the copy protection on the original Gameboy.
So Nintendo makes the Gameboy, and they only want authorized games to be used in the system. But how can they stop someone from looking at the hardware and making a compatible game without paying a license fee?
Well, they build a check into the hardware for a specific set of assembly code on the cartridge. If your cart doesn't have that exact assembly it won't boot up.
The code?
It displays the Nintendo logo on the screen and plays their jingle.
That way, if you did make an unauthorized cartridge, you'd have to infringe on their trademark in order to make the game playable.
Nintendo wasn't actually the first company to implement cartridge logo checks. Sega did it first with their "Trademark Security System" or TMSS, which worked in pretty much the same way, but then lost in a US court case against Accolade as the judges deemed that anything strictly required for games to work could not be protected by copyright or trademark law.
Despite the precedent however, the same idea kept popping up in many subsequent consoles and even some non-gaming products:
- The original PlayStation reads the logo that gets displayed on the startup screen from the first 16 sectors of the disc. Notably, US consoles will not validate the logo against a known good copy - possibly hinting at the fact Sony was aware of the TMSS case - but Japanese and late European models will.
- Similarly, PS2 games must contain a bitmap of the startup screen logo in the first 16 sectors of the disc, and PS3 games are required to have a PNG of the original PS3 logo in their filesystem.
- Xbox 360 hard drives must have a PNG of the Microsoft logo in their "security sector", which among other things contains a digitally signed copy of the drive's serial number to ensure third party drives cannot be used.
- macOS will refuse to boot in a VM or on non-Apple hardware unless the BIOS can provide a supposedly copyrighted (but otherwise well known) 64-character string.
- The handshaking process for establishing a connection to an Oracle database server involves sending a string that clearly states it is property of Oracle and protected by copyright law.
> This has however been rendered pointless once the courts ruled in Accolade's favor in Sega v. Accolade, where Sega's trademark enforcement system was questioned as being monopolistic, and bypassing it by third parties on the grounds that it is for the purposes of lawful interoperability was ruled as fair use.
So Nintendo makes the Gameboy, and they only want authorized games to be used in the system. But how can they stop someone from looking at the hardware and making a compatible game without paying a license fee?
Well, they build a check into the hardware for a specific set of assembly code on the cartridge. If your cart doesn't have that exact assembly it won't boot up.
The code?
It displays the Nintendo logo on the screen and plays their jingle.
That way, if you did make an unauthorized cartridge, you'd have to infringe on their trademark in order to make the game playable.