Patent ID: 7051370

Claim:
A content-certified e-mail service system having an e-mail content certifying device for certifying contents of a text of an e-mail sent from an e-mail terminal device at a sender's side to an e-mail terminal device at a receiver's side within a network, wherein: said e-mail terminal device at the sender's side sends a content certification request e-mail to said e-mail content certifying device, said content certification request e-mail containing an e-mail address of said e-mail terminal device at the receiver's side and a text of content certification; said e-mail content certifying device judges, upon receipt of said content certification request e-mail, whether there is any tampering with said text of content certification in said e-mail; said e-mail content certifying device, upon judging that there is no tampering with said text of content certification, saves registration information that contains said text of content certification in a storage device, sends a content-certified e-mail that contains said text of content certification to said e-mail terminal device at the receiver's side, and sends a receipt e-mail that contains receipt information indicating that content certification has been effected to said e-mail terminal device at the sender's side; said e-mail terminal device at the sender's side sends a review request e-mail to said e-mail content certifying device, said review request e-mail containing said receipt information in said receipt e-mail; said e-mail content certifying device, upon receipt of said review request e-mail, retrieves one set of registration information corresponding to an identifier in said review request e-mail from said storage device, and judges whether there is any tampering with the receipt information in said review request e-mail based on said one set of registration information retrieved; and said e-mail content certifying device, upon judging that there is no tampering with the receipt information in said review request e-mail, sends an e-mail containing said text of content certification to said e-mail terminal device at the sender's side.