Patent ID: 7835993
Filing Date: 2010-11-16
Classification: G06F,H04L

Abstract:
1. A license management device which manages a license, the license being information which indicates a right to use a content under a predetermined usage rule, said license management device comprising: a license type identifying unit programmed to identify a license type which represents whether or not a license includes a usage rule which requires updating each time a content is used; a license accumulation unit programmed to perform different accumulation processing, depending on whether or not the license includes a usage rule which requires updating each time a content is used; a unique information managing unit programmed to hold a unique key which is unique to said license management device; a domain information managing unit programmed to hold a domain key held in common with said device and another license management device within a domain that consists of a plurality of predetermined license management devices; a content decrypting/reproducing unit programmed to use the content in accordance with the usage rule included in the license; and a license-type change determining unit programmed to determine whether or not the license type identified by said license type identifying unit has changed due to the use of a content by said content decrypting/reproducing unit, wherein said license accumulation unit includes a license accumulation control unit programmed to encrypt the license, as the accumulation processing: by using the unique key, which is held by said unique information managing unit, in a case where the license includes the usage rule which requires updating each time a content is used; and by using the domain key, which is held by said domain information managing unit, in a case where the license does not include the usage rule which requires updating each time a content is used, the different accumulation processing is processing for accumulating the license encrypted by said license accumulation control unit, and said license accumulation control unit is programmed to;