A method and system for transferring electronic media information over a public network in such a way as to provide safeguards for inappropriate distribution of copyright or otherwise protected materials are described. The media information is transparently watermarked with a unique ID, such as one generated from X.509 Digital Certificate and public-key cryptography public/private key pairs, such that the information can be identified as belonging to a particular individual. A system and method for monitoring the movement of such watermarked files, positively identifying people who have inappropriately distributed copyright materials over a public network without permission, and taking appropriate enforcement action against such people.