| 摘要 |
PROBLEM TO BE SOLVED: To provide a key distribution system which traces the receiving apparatus of a leak source, even if an unauthorized receiving apparatus embedded with an intermediate key by an attacker is produced. SOLUTION: The key distribution system 1 is constituted of a channel 10, a key-issuing center 11, a server 12, and a plurality of receiving apparatuses 13a to 13n. The key-issuing center 11 distributes a system secret variable group set SPGS of necessary information for distributing a sharing key SK to the receiving apparatuses 13a to 13n to the server 12, and distributes an individual information group EMMG necessary for receiving the sharing key SK from the server 12 to a plurality of receiving apparatuses 13a to 13n. The server 12 generates the sharing key SK, generates a common information ECM, based on the sharing key SK and the system secret variable group set SPGS, and distributes the common information ECM to a plurality of receiving apparatuses 13a to 13n. The receiving apparatuses 13a to 13n acquire the sharing key SK, based on the individual information group EMMG and the common information ECM and output to the outside. COPYRIGHT: (C)2005,JPO&NCIPI
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