Copy prevention circuit capable of preventing a copy of image/aural sound signals without change of data structure in digital transmission

摘要

Multiplexed stream information of image / aural sound / data, etc. processed by stream processing means (1) is separated into image / aural data and other data by the stream identification means (3) and one is output to the regenerative processing means (8, 9) via descramble means (2) and the other is connected to a data bus such as a PC, via scramble key discriminating means (5) and the I / means (6). The scramble key discriminating means (5) discriminates a data format of the signal output to the data port upon reception of scramble key information of scramble key extracting means (4) and does not output to the data bus by abolishing the information judged to be the scramble key relative to the image or the aural sound, but outputs only the scramble key excluding the image / aural sound.