the invention relates to a method and system for embedding in a digital media file user fingerprint which the user cannot detect when using the digital media file . in the method , a user - detectable watermark is first embedded in the digital media file . this watermark can be transformed in a client device to a non - detectable fingerprint of the user by utilizing digital media file - specific information issued by a digital media rights owner when the user has bought a user license . afterwards the digital media rights owner can read the embedded user fingerprint from the digital media file if it is illegally distributed between other users .