Quake shareware CD hid full id Software catalog — pirates cracked it in 39 days

Fabien Sanglard, a developer and technical blogger, has published a detailed analysis of the peculiar Quake shareware CD-ROM release. The demo itself occupied only 22 MB of the 640 MB capacity of a standard CD-ROM. John Carmack once joked that if id Software ever released a CD version of Doom, it would have to include a "Making of Doom" feature film to fill the remaining space. Instead, the company put the extra capacity to a different use.

id Software decided to fill the empty space with encrypted copies of its entire back catalog, including Wolfenstein 3D, Spear of Destiny, Doom, Doom II, and Heretic. The idea was that users could call a premium-rate hotline, pay for a game over the phone, and receive an unlock code. The same mechanism was used to upgrade the Quake shareware into the full version. In the pre-digital distribution era, when most people lacked fast internet connections, this seemed like a clever solution.

However, the scheme had a fatal flaw. Just 39 days after the CD-ROM hit store shelves, Quakecrk.zip appeared on the internet. Inside was Qcrack.exe, a tool that could generate decryption codes for every game on the disc. The crack allowed users to unlock all titles without paying a cent.

Sanglard explains that the encryption algorithm was relatively simple, and the fact that unlock codes were transmitted over the phone made them easy to intercept. The story serves as a classic example of how even well-intentioned copy protection can fail when attackers have physical access to the medium. The Quake shareware CD remains a fascinating piece of gaming history, showing both the ingenuity and the limitations of pre-internet distribution methods.