Patent ID: 8560842

Claim:
A communication apparatus comprising: a storage device storing computer readable instructions and comprising a device setting table, an address table and a certificate table; and a processor configured to execute the computer readable instructions, wherein the computer readable instructions cause the processor to implement: registering an e-mail address of a first communication apparatus in the address table, upon receiving a request to register the address of the first communication apparatus; retrieving a certificate exchange setting registered in the device setting table upon receiving the request to register the address of the first communication apparatus in the address table; determining whether the retrieved certificate exchange setting indicates that the communication apparatus is configured to require a certificate to transmit data to another communication apparatus; transmitting a first command to the e-mail address of the first communication apparatus in response to the determination that the retrieved certificate exchange setting indicates that the communication apparatus is configured to require a certificate to transmit data to another communication apparatus, wherein the first command is for requesting a first public key corresponding to a first secret key of the first communication apparatus; receiving the first public key from the first communication apparatus; registering the first public key in the certificate table in association with the e-mail address of the first communication apparatus; generating first encrypted data by encrypting first data using the first public key included in the certificate table when receiving a request to transmit the first data to the e-mail address of the first communication apparatus; and transmitting the first encrypted data to the e-mail address of the first communication apparatus.