| 摘要 |
PURPOSE:To enable the reference of only specified partial data according to a reference processing stage of a data without complicating the processing of a data offer side. CONSTITUTION:The same number of cipher keys as the number of reference processing stages are generated or set beforehand in the data offer side 101, and when the data user ciphers the specified partial data corresponding to the reference processing stage by a cipher key corresponding to the reference processing stage, a ciphering partial data set ciphering all partial data referred after next stage by the cipher key corresponding to the reference processing stage is added to the specified partial data of the reference processing stage, and a processing ciphering a data set consisting of the specified partial data and the ciphering partial data set by the cipher key different from the next reference processing stage is performed by the same number of times as the number of reference processing stages, and the whole data set are ciphered to be offered to the data user, and the data user side 102 deciphers using the cipher key corresponding to the reference processing stage in order of the reference processing stage. |
