Device and method for the copy-protected distribution of electronic documents

#The invention relates to a device for the copy-protected distribution of electronic documents in a publicly accessible electronic data network, in particular the internet, in accordance with the preamble to claim 1. In addition, the invention relates to a method for the copy-protected distribution of electronic documents, in particular to the operation of such a device.

#Due to the rapidly expanding use of the internet as a distribution medium, to exchange and sell electronic documents—in this case, as well as text files, this includes in particular audio, video, animation, simulation and program files and mixtures of these—, effective access control, particularly for valuable, copyright-protected files and the prevention of unauthorized further distribution of copies produced without authorization is an increasing problem.

#Existing, common methods for improving the copyright protection of (user) files distributed electronically via public data networks concern on the one hand conventional methods for encoding user files of this kind and on the other it is now also common to incorporate so-called electronic water marks in (lawfully distributed) copies of an electronic document, namely individualized electronic markings, which—invisible to the users of the documents in normal use—nevertheless enable a document to be precisely identified (with the possible objective of enabling the identification of the origin of copies distributed without authorization).

#Other advantages, features and details may be derived from the following description of preferred examples of embodiments and using the diagrams—these are

#FIG. 1: a schematic block diagram of the device for the copy-protected distribution of electronic documents in accordance with a first, preferred embodiment

#FIG. 2: a schematic block diagram with an example of the realization of the encoding unit 24 from FIG. 1.

#The system graphically represented in FIG. 1 separates by means of symbolic limits 10 a publicly accessible data network, in this case the world wide web (www) as an internet system 12, from a provider 14, in this case a provider of digital audio documents to be sold via the network 12 and from a user 16, who, by means of a symbolically shown access unit 18 (usually a computer unit fitted with common internet access software) is able to access in an otherwise known manner an accessible document server unit 20 via the electronic data network 12. This takes place by means of generally accessible, common internet protocols, for example TCP-IP, HTTP or FTP, with the document server unit 20 being designed to display a selection of different electronic documents for a (word missing) accessible by means of the station 18 and to subsequently facilitate the downloading of a selected electronic file.

#Insofar, this is standard technology according to prior art which requires no further explanation.

#The documents offered in accordance with this example of an embodiment are so-called sound or music files compiled using the MP3 file format and which may be played on a suitable playback device 22, which particularly preferably is part of the user-end access unit 18 or allocated to this (player or viewer as playback unit; these are suitable for reading the MP3 file format and converting it back into audio signals or music; once again, this has been long known from prior art).