ENCRYPTION DEVICE WITH ACCESS RIGHT, CRYPTOGRAPHIC SYSTEM WITH ACCESS RIGHT, ENCRYPTION METHOD WITH ACCESS RIGHT AND ENCRYPTION PROGRAM WITH ACCESS RIGHT

摘要

PROBLEM TO BE SOLVED: To generate an encrypted file which includes one encrypted common key and can be decrypted by one or more decryption enabled persons.SOLUTION: A data encryption section 140 uses a random number as a common key to encrypt access limit data 111 in accordance with a common key cryptographic system. The data encryption section 140 encrypts the random number used as the common key in accordance with a cryptographic system with an access right while using a public key and access right information 112 indicating a decryption enabled condition. A data decryption section 150 uses a user private key 192 to decrypt an encrypted random number 119a of an encrypted file 119 into the random number. The data decryption section 150 uses the decrypted random number as a common key to decrypt encrypted data 119b of the encrypted file 119 into the access limit data 111 in accordance with the cryptographic system with the access right.