Patent ID: 7693795
Filing Date: 2010-04-06
Classification: G06F,G11B

Abstract:
1. A recording device for encrypting a digital work that corresponds to a permission range within which the digital work is permitted to be used and for recording the digital work in encrypted form to a recording medium, the recording device comprising: a memory device that stores a program, the program when executed causes the recording device to operate as: a digital work acquiring unit that acquires the digital work and range information indicating the permission range in which the digital work is permitted to be used, the permission range including a plurality of subranges, the plurality of subranges being different from other respective subranges, and the range information including a plurality of adoption information, each of the plurality of the adoption information being corresponded to one of the plurality of the subranges and indicating whether a corresponding subrange is to be adopted; a judging unit that judges whether each piece of adoption information indicates that a corresponding subrange is to be adopted; a key acquiring unit that acquires a subrange key for each subrange indicated to be adopted by the corresponding adoption information when the corresponding adoption information indicates that the corresponding subrange is to be adopted, thereby acquiring one or more subrange keys; a key generating unit that generates an encryption key using the one or more acquired subrange keys; an encrypting unit that encrypts the digital work based on the encryption key, thereby generating encrypted information; and a writing unit that writes the range information and the encrypted information to the recording medium.