| 摘要 |
PROBLEM TO BE SOLVED: To provide a communication technique which allows encrypted pieces, which are distributed in a content distribution system, to be combined uniquely per communication device and is capable of improving the flexibility of system construction. SOLUTION: A node 51 stores a node ID string, an encrypted symmetric key string, and encrypted pieces in association with each other when receiving them from other nodes 50 and 51. The node 51 outputs new encrypted pieces resulting from further encryption of the encrypted pieces using random numbers as symmetric keys, and encrypted symmetric keys resulting from encryption of the symmetric keys using a public key, in response to requests from the another nodes 51. The node 51 transmits a node ID of the node 51 itself in addition to node IDs stored in association with encrypted pieces, the encrypted symmetric keys output from the node 51 itself in addition to encrypted symmetric keys stored in association with the encrypted pieces, and the new encrypted pieces to the other nodes 51. COPYRIGHT: (C)2010,JPO&INPIT |
