System for preventing an illegal copy of digital contents

摘要

In order to prevent an illegal copy of an encoded digital content downloaded by users for reproduction, all systems connected to the users generate a plurality of keys which are mutually shared, and download and upload the digital content by using channels formed between units performing mutual communication A unit for supplying the digital content receives an authorization of legally supplying the digital content from an authorization recognition unit. A first content output unit (40) is authenticated form a digital content supplying unit (30). At this time, the digital content supplying unit (30) and the first content output unit (40) form a sharing key to form a channel between the two. A second content output unit (50) is authenticated from the digital content supply unit (30) through the first content output unit (40), the first content output unit (40) and the second content output unit (50) form a channel to the channel key. The digital content between the first content output unit (40) and the second output unit (50) is downloaded and uploaded according to respective control state data of the first content output unit (40) and the second output unit (50). Accordingly, the digital content transmitted between the digital content supply unit (30), the first content output unit (40), and the second content output unit (50) can be prevented from an illegal copy. <IMAGE>