METHOD FOR DESCRIBING PERMISSION INFORMATION AND DEVICE FOR FORMING DATA WITH COPYING GUARD

摘要

PURPOSE:To provide the method for describing the permission information to prevent the illegal change of a permission state by the diversion from other data or rewriting of codes, etc., the device for forming the data with a copying guard and a recording and reproducing device. CONSTITUTION:The codes 2 obtd. by subjecting properly formed codes 1 to unidirectional conversion (f) are formed as the codes to indicate the permission information of respective categories. The codes 1 and the codes 2 are described in parallel at the time of indicating the permission and only the codes 2 are described at the time of indicating inhibition. Then, the formation of the codes 1 from the codes 2 is infeasible and the formation of the codes of the permission state from the inhibition state is difficult. The rewriting of the permission codes with the other permission codes is made difficult by integrating the codes 2 of all the categories and ciphering the data for protecting these codes as a ciphering key.