METHOD AND SYSTEM FOR CANCELING ELECTRONIC MAIL

摘要

PROBLEM TO BE SOLVED: To prevent an electronic(E) mail transmitted to an error destination address from being opened by an owner of an information processing terminal of the address. SOLUTION: An E mail server 51 transmits a normal E mail transmitted from a client 71 to an E mail server 52. Also when an E mail cancel requesting E mail is transmitted from the client 71, the server 51 executes similar processing. At the time of receiving a normal E mail, the server 52 temporarily stores the received E mail in a prescribed storage area, and after the lapse of prescribed time, transmits the E mail to a client 91. At the time of receiving the E mail requesting the cancel of the E mail before the lapse of the prescribed time, the server 52 respectively verifies two digital signatures in the cancel requesting E mail by using a disclosed key for verifying a user's digital signature previously provided from the client 71 to check whether the signature is altered or not and whether a transmitter is the same or not. When the signature is not altered and the transmitter is the same, the contents of the normal E mail are compared with that of the cancel requesting E mail, and when both the contents are different from each other, the normal E mail is canceled in accordance with the contents of an instruction described in the header part of the cancel requesting E mail.