Cryptographic Document Attribution: A Forensic System via Emergent Steganography

We present a practical, cryptographically sound system for the forensic attribution of high-value document leaks. By leveraging the emergent steganography framework [1], the system embeds recipient-specific identifiers within documents using dynamically generated, unique hiding algorithms. Crucially, these identifiers are recoverable even after the document undergoes analog conversion (e.g., printing, photography, scanning). The system incorporates a trusted timestamping authority to provide non-repudiable proof that the watermark was embedded prior to distribution, defeating post-facto forgery claims. This work transforms leak investigations from reliance on circumstantial evidence to the production of court-admissible, cryptographic proof.