Method for transmitting message, involves sending enquiry by sender to directory service whereby sender encrypts message using gateway key and transmits to recipient address via mail gateway which decrypts message

摘要

The method involves sending of an enquiry by a sender to a directory service. The directory service looks for a recipient address in a key directory (8) on the basis of enquiry. A key generator (12) generates a gateway key (13) in response to the enquiry and informs the sender of the gateway, if the key directory does not contain the recipient address. The sender encrypts the message using the gateway and transmits to the recipient address via a mail gateway (11) which decrypts the message : Independent claims are also included for the following: (A) System for transmitting a message; and (B) Key generator.