Technology
Research reveals MS Paint embeds server-issued GUID watermarks in locally generated AI images
Reverse engineering shows Microsoft Paint and Photos use remote servers to moderate prompts and issue tracking identifiers for local image generation.
The short version
- Reverse-engineering research indicates Microsoft Paint and Photos send user prompts to a remote Azure moderation server before generating images locally.
- The remote server returns a unique 16-byte watermark GUID that is invisibly embedded directly into the pixel data of locally generated output.
- Paint also attaches signed C2PA provenance metadata matching the invisible watermark GUID to saved image files.
- If the invisible watermarking step fails during local generation, the Paint application cancels the operation and returns an error.
Key facts
- Microsoft Paint and Photos include local ONNX model files to support local AI image generation on Windows.[Hacker News]
- Before executing local generation, the apps send prompts to an external Azure moderation server.[Hacker News]
- The moderation endpoint returns a revised prompt, prompt generation ID, human reference flag, and a 16-byte watermark GUID.[Hacker News]
- Paint's Watermarker.dll embeds the server-issued GUID into the image pixels using a block-domain, SVD-style invisible watermark.[Hacker News]
- Paint halts generation and raises an error if the invisible watermarking function fails.[Hacker News]
- Saved images in supported formats include signed C2PA manifest metadata containing the same GUID as a soft binding.[Hacker News]
What remains uncertain
- It is unknown how widely Windows users actively utilize the local AI image generation features in Paint and Photos.[Hacker News]