Patent ID: 8015399

Claim:
A communication apparatus comprising: first and second digital certificates, the second digital certificate corresponding to a regular public key, the first digital certificate corresponding to a rescue public key, the first digital certificate having a validity term that is longer than the validity term of the second digital certificate; an authentication part configured to authenticate another communication apparatus with the first digital certificate when communicating with the another communication apparatus and when the validity term of the second digital certificate is expired; a certificate transmission part configured to transmit a new second digital certificate when the authentication part succeeds in authenticating the other communication apparatus with the first digital certificate; and a request management unit that stores a criterion to determine execution of an operation according to a request from the another communication apparatus, and allows operations of the communication apparatus to be executed such that all of the operations are allowed to be executed when the another communication apparatus is authenticated by the second digital certificate according to the stored criterion, and only an operation of transmitting the new second digital certificate is allowed when the another communication apparatus is authenticated by the first digital certificate.