Patent ID: 7587593
Filing Date: 2009-09-08
Classification: H04L

Abstract:
1. An electronic device, comprising: a memory configured to store first authentication information; a first interface configured to communicate with an external electronic device connected to the electronic device via a data bus; an authentication unit configured to conduct authentication processing with the external electronic device by exchanging the stored first authentication information and receiving second authentication information from the external electronic device; a second interface configured to receive third authentication information; a first buffer memory configured to store the second authentication information received from the external electronic device, set a first flag in response to the storage of the second authentication information, and increment a first generation counter in response to the storage of the second authentication information; a second buffer memory configured to store the third authentication information received via the second interface, set a second flag in response to the storage of the third authentication information, and increment a second generation counter in response to the storage of the third authentication information; an update control unit configured to compare, when the first flag is set, the incremented value of the first generation counter against a previous value of the generation counter stored in the first buffer memory, compare a version of the second authentication information to a version of the stored first authentication information when the incremented value of the first generation counter is greater than the previous value of the generation counter stored in the first buffer memory and update the first authentication information stored in memory based on the second authentication information when it is determined that the version of the second authentication information is newer than the stored first authentication information; and the update control unit configured to compare, when the second flag is set, the incremented value of the second generation counter against a previous value of the generation counter stored in the second buffer memory, compare a version of the third authentication information to a version of the stored first authentication information when the incremented value of the second generation counter is greater than the previous value of the generation counter stored in the second buffer memory and update the first authentication information stored in memory based on the third authentication information when it is determined that the version of the third authentication information is newer than the stored first authentication information.