摘要 |
<p><P>PROBLEM TO BE SOLVED: To prevent illegal copying and to enable private copying within a lawful extent in an optical disk device. <P>SOLUTION: An optical disk player encrypts and outputs a digital signal read from an optical disk. When the input digital signal is an encrypted signal, an optical disk recorder decodes the signal, limits the digital reading of a CDS-200, obtains an intrinsic ID to specify a user from an ID device, and writes its as a permission ID in an optical disk together with contents. The optical disk player authenticates reproduction from a copied optical disk based on the permission ID and the intrinsic ID recorded in the optical disk. Thus, illegal copying from the optical disk is prevented, and the effect of enabling private copying within a lawful extent is provided. <P>COPYRIGHT: (C)2004,JPO&NCIPI</p> |