| 摘要 |
PROBLEM TO BE SOLVED: To reduce information leakage due to illegal access to a mail server on an external network without preliminarily receiving or storing electronic mail from the mail server in the case of allowing the mail server to store the electronic mail.SOLUTION: A gateway 10 includes: an encryption control part 14 for acquiring unencrypted electronic mail stored in a mail server 2, and for allowing an encryption part 13 to encrypt the electronic mail, and for transmitting the electronic mail to the mail server, and for replacing the unencrypted electronic mail with the transmitted encrypted electronic mail; and a relay control part 16 for, when the electronic mail acquired from the mail server 2 in response to a reception request from a client 1 is encrypted, allowing a decryption part 15 to decrypt the electronic mail, and for transmitting the decrypted electronic mail to the client 1.SELECTED DRAWING: Figure 1 |
