Patent ID: 7177841

Claim:
A digital contents distribution system having a client, a digital contents server, a roaming server, and a network connected between the client, the digital contents server, and the roaming server, wherein said roaming server comprises means: for receiving from the digital contents server a digital content protected by a first intellectual property right protection system, wherein the digital content includes information uniquely specifying the first intellectual property right protection system protecting the digital content; means for receiving from said client, in a case where said client cannot process said first intellectual property right protection system, change request information for changing the first intellectual property right protection system to a second intellectual property right protection system that said client can process; means for changing the first intellectual property right protection system protecting the received digital content to said second intellectual property right protection system based on the change request information, wherein said means for changing the first intellectual property right protection system also changes the information uniquely specifying the first intellectual property right protection system protecting the digital content to information uniquely specifying the second intellectual property right protection system; and means for transmitting the digital content protected by the second intellectual property right protection system to said client, wherein the first and second intellectual property right protection systems each comprise an IPMP System, and wherein IPMPS Type in IPMP Descriptor IPMP Message prescribed in ISO/IEC SC29 14496-1 IS:1998 is used to identify the IPMP system.