INFORMATION PROTECTING METHOD AND CIPHERING DEVICE USING THE SAME

摘要

PURPOSE:To realize the information protecting method and ciphering device which have high evidence ability by disabling both an information sender and a receiver to forge information. CONSTITUTION:An electronic signature method which uses open key ciphers makes the ciphering key of signature information secret even to the sender. Consequently, the information sender ciphers the signature information 10 with the secret key by using a closed ciphering device 1 and sends the ciphered information to the receiver together with the original information. The receiver deciphers it by using the open key to confirm the information sender. Further, the time when the ciphered signature is generated is included in the signature by a composing circuit 14 to prevent the sender from generating wrong information.