DIGITAL DATA ENCRYPTION SYSTEM, DIGITAL DATA REPRODUCING DEVICE, DIGITAL DATA ENCIPHERING METHOD, DIGITAL DATA REPRODUCING METHOD AND PROGRAM FOR MAKING COMPUTER EXECUTE THE METHOD

摘要

PROBLEM TO BE SOLVED: To protect the copyright of digital data, without imposing constraints on the use condition of a personal computer or the like, or affecting the costs of a digital data reproducing device.;SOLUTION: An input means 102 reads copyright digital data stored in a recording medium, such as CD-ROM, and an arithmetic means 103 selects a plurality of cryptographic algorithms set by a setting means 105 from a cryptographic arithmetic formula preparing parameter, and enciphers the copyright digital data according to the cryptographic arithmetic formula which is decided based on the selection. A file means 104 creates not only the enciphered digital data but also an index value and the cryptographic arithmetic formula preparing parameter in the same file, and outputs it to a flash memory. A reproduction device obtains the cryptographic arithmetic formula from the index value and the cryptographic arithmetic formula preparing parameter in the same file as that of the enciphered digital data, and reproduces digital data by carrying out corresponding decoding processing.;COPYRIGHT: (C)2003,JPO