Patent ID: 8966644
Filing Date: 2015-02-24
Classification: G06F

Abstract:
1. An information storing device comprising: a storage section configured to store first revocation information that is a list of an identifier of an unauthorized device; and circuitry configured to execute determination processing of unauthorized equipment in accordance with the first revocation information, wherein the circuitry extracts first version information that indicates a first version number of the first revocation information enabling identification of issue order of the first revocation information from the first revocation information, sets a first message authentication code based on the first version information and transmits the extracted first version information and the first message authentication code to a communication counterpart device, the circuitry is configured so that (1) when the circuitry receives a request for transmitting the first revocation information from the communication counterpart device, the circuitry transmits first revocation information including first signature information, and (2) when the circuitry receives second revocation information held by the communication counterpart device from the communication counterpart device, the second revocation information including second signature information, the circuitry checks whether a second version number of issue order of the second revocation information is newer than the first version number, and when the second version number is newer than the first version number, the circuitry verifies the second signature information by applying a public key of a certificate authority stored in the storage section, and when the second signature information is verified, the circuitry executes revocation information synchronization processing of substituting the second revocation information of the second version for the first revocation information of the first version stored in the storage section to store the second revocation information of the second version, sets a second message authentication code based on the second version information, and transmits the second message authentication code to the communication counterpart device.