| 摘要 |
A storage stores a common key table containing a plurality of kinds of common keys usable for the communications with other communication apparatuses within the same system, its own identification information, and an update key associated with the identification information. The transmitter transmits the identification information to a system management apparatus for managing the common key table used in the system, the identification information on the communication apparatuses within the system, and the update key associated with the identification information. An acquiring unit acquires, from the system management apparatus that has received the identification information, a common key table for use in update (updating common key table) encrypted using the update key associated with the identification information. A decryption unit decrypts the encrypted updating common key table by use of the update key stored in the storage. |
