Microsoft Paint and Photos Embed Hidden 128-Bit Device Identifiers in AI Images
Security researcher Xusheng Li discovered that Microsoft Paint and Photos embed a hidden 128-bit Global Device Identifier (GDID) into AI-generated images. This identifier links the generated media directly to specific Windows 11 installations. This discovery raises major privacy concerns, as it allows Microsoft or third parties to trace AI-generated content back to a user's physical device. It highlights the tension between content provenance tracking and user anonymity in the AI era. The embedding is handled by a component named `Watermarker.dll` and occurs even if the visible Copilot watermark option is turned off. Additionally, the same watermark ID is written into the C2PA metadata as a "soft binding" value to link the image pixels with the provenance metadata.
## BACKGROUND
A Global Device Identifier (GDID) is a permanent, unique digital fingerprint assigned by Microsoft to a computer during Windows installation, which cannot be fully disabled. The Coalition for Content Provenance and Authenticity (C2PA) is an open industry standard that uses cryptographically signed metadata to verify the origin and history of digital media.