Redo-San

Free, browser-based digital authenticity toolkit (GPL-2.0). Watermark images (9 algorithms), audio (8) and documents (5); compute 21 fingerprint hashes; sign and verify C2PA provenance; issue Ed25519/P-256 DIDs and downloadable PDF/DOCX/EPUB/OTS certificates; run ELA, noise and JPEG-marker ... [More] forensics. Everything runs locally in the browser so files never leave the machine. A matching Node CLI (redosan-authenticity-cli) is published separately. Honest scope: not a full PDF editor - watermarking, provenance and verification only. [Less]