| 摘要 |
PROBLEM TO BE SOLVED: To provide a device capable of making the unauthorized use of the enciphered information difficult and easily using a software without impairing convenience. SOLUTION: A recording medium includes a reproduction-only part where the enciphered information is recorded and a rewrite part where the key information that is converted into the decoding key information and the algorithm selection information that selects an algorithm to generate the decoding key information are recorded. A recording/reproducing device includes a control part 204 which performs the control to read out the enciphered information, key information and algorithm selection information on the basis of the designated information, a rewrite area recording/reproducing part 202 which reads out the information on the rewrite part, a reproduction area reproducing processing part 203 which reads out the information on the reproduction-only part, an algorithm data-base part 205 which stores the algorithm, a transposition converting part 206 which converts the key information into the decoding key information by means of the algorithm and an enciphered information decoding part 207 which decodes the enciphered information by means of the decoding key information. |
