David Plummer, a former Microsoft engineer, was the primary author of Windows XP's Product Activation system, which included the infamous product key FCKGW. This key became widely used on pirated copies of the operating system. Plummer created the activation system by compressing and encrypting disc data, ensuring its security. The FCKGW key was specifically tied to certain data configurations, making it ineffective on standard XP CDs. A piracy group, Devils0wn, leaked a complete Windows XP Pro Corporate ISO and the valid FCKGW key just five weeks before the official launch, allowing unauthorized installations. Microsoft responded by blacklisting product IDs associated with the compromised keys in Service Pack 1 and blocking updates for installations using the FCKGW key in Service Pack 2. Valid, un-leaked Volume License Keys (VLKs) remained functional for years after the incident. Plummer noted that the media and the key were leaked before the product reached stores, preventing the intended hardware-binding from functioning.