Patent ID: 7152159

Claim:
An encrypted mail transmission system, comprising: an e-mail transmission device configured to generate an e-mail with a digital signature by encrypting an e-mail directed to an e-mail reception device, and to transmit the e-mail with the digital signature; an e-mail server device configured to: receive, from the e-mail transmission device, an e-mail directed to the e-mail reception device; determine whether the received e-mail is the e-mail with the digital signature; transmit to the e-mail reception device a notification indicating that the received e-mail is stored in the e-mail server device, when it is determined that the received e-mail is the e-mail with the digital signature, the notification including information specific to a destination of the received e-mail, the notification being distinct from the received e-mail, and transmit to the e-mail reception device the received e-mail without the digital signature, when it is determined that the received e-mail is not the e-mail with the digital signature; and an e-mail reception device, comprising: an input device configured to input information specific to a user of the e-mail reception device; and a controller configured to: receive, from the e-mail server device, the notification; determine whether the information specific to the destination of the received e-mail included in the received notification is consistent with the information specific to the user of the e-mail reception device input by the input device; retrieve, from the e-mail server device, the received e-mail with the digital signature when the notification is received and when it is determined that the information specific to the destination of the received e-mail is consistent with the information specific to the user of the e-mail reception device, and decrypt the received e-mail with the digital signature.