Encoding message sending and receiving method, at the transmission person device, the receiving believer device, the encoding message sending and receiving system and

摘要

PROBLEM TO BE SOLVED: To prevent an encrypted sentence from being decrypted by a key server regarding continuous messages between a sender and a recipient without requiring pre-setting for the recipient.;SOLUTION: A sender apparatus 1 calculates a temporary shared key from an identifier of a recipient and a private key of a sender, uses this shared key to encrypt a transmission message and transmits it to a recipient apparatus 2 together with a public key of the sender. When a key server 3 successfully authenticates the recipient apparatus 2, a specific key of the recipient is transmitted to the recipient apparatus 2, the recipient apparatus 2 calculates a temporary shared key from the specific key of the recipient and the public key of the sender, and decrypts the message. The recipient apparatus 2 calculates a shared private key from the public key of the sender and a private key of the recipient and transmits a public key of the recipient to the sender apparatus 1. The sender apparatus 1 calculates the same shared private key from the public key of the recipient and the private key of the sender. The sender apparatus 1 and the recipient apparatus 2 use the shared private key to encrypt or decrypt messages transmitted/received continuously.;COPYRIGHT: (C)2009,JPO&INPIT