Patent ID: 7822981

Claim:
A communication apparatus that performs authentication for a connection with another communication apparatus and then performs communication with the other communication apparatus, the communication apparatus comprising: a state management unit configured to manage a state in the authentication as one state among a plurality of predetermined states; a duplication detection unit configured to detect, in a specified state among the plurality of states, a duplicate receipt of a message related to authentication transmitted from the other communication apparatus; and an authentication unit, wherein, in the specified state, the communication apparatus receives, from the other communication apparatus, the message related to authentication of one type among predetermined types, said duplication detection unit is configured to specify a time period for each predetermined type of message, to measure the time period, and to detect whether or not the communication apparatus has the duplicate receipt of the message related to the authentication within the specified time period, and said authentication unit is configured to continue an authentication operation in the case where said duplication detection unit does not detect the duplicate receipt of the message related to the authentication within the specified time period but receives the message related to the authentication and to stop the authentication operation in the case where the duplicate receipt of the message related to the authentication is detected by said duplication detection unit within the specified time period.