Discovering, detecting, and surgically removing Google's AI watermark

Summary

Reverse-Engineering SynthID Discovering, detecting, and surgically removing Google's AI watermark through spectral analysis This project reverse-engineers Google's SynthID watermarking system - the invisible watermark embedded into every image generated by Google Gemini. Using only signal processing and spectral analysis (no access to the proprietary encoder/decoder), we: Discovered the watermark's resolution-dependent carrier frequency structure Built a detector that identifies SynthID watermarks with 90% accuracy Developed a multi-resolution spectral bypass (V3) that achieves 75% carrier energy drop, 91% phase coherence drop, and 43+ dB PSNR on any image resolution 🚨 Contributors Wanted: Help Expand the Codebook We're actively collecting pure black and pure white images generated by Nano Banana Pro to improve multi-resolution watermark extraction. If you can generate these: Resolution: any (higher variety = better) Content: fully black (#000000) or fully white (#FFFFFF) Source: Nano Banana Pro outputs only Generate a batch of black/white images by attaching a pure black/white image into Gemini and prompting it to "recreate this as it is" Place them in new folders: gemini_black_nb_pro/ (for black) gemini_white_nb_pro/ (for white) Open a Pull Request 🚀 These reference images are critical for: Carrier frequency discovery Phase validation Improving cross-resolution robustness Even 150–200 images at a new resolution can significantly improve detection and removal. What Makes This Different Unlike brute-force approaches (JPEG compression, noise injection), our V3 bypass uses a multi-resolution SpectralCodebook - a collection of per-resolution watermark fingerprints stored in a single file. At bypass time, the codebook auto-selects the matching resolution profile, enabling surgical frequency-bin-level removal on any image size. The Watermark is Resolution-Dependent SynthID embeds carrier frequencies at different absolute positions depending on image resolution. A codeboo...