Privacy protection device, privacy protection method and database creation method

摘要

PROBLEM TO BE SOLVED: To provide tabulation data for improving partial sum precision and supporting a non-negative restriction together while satisfying a differential privacy reference.SOLUTION: A privacy protection device 10 includes: a first conversion section 12 for applying first linear conversion to first tabulation data V to generate first series data W; a random number application section 13 for applying a random number of a predetermined strength to each of elements included in the first series data W to generate second series data W; a precision section 14 which performs precision processing for correcting each of elements included in the second series data Wunder a predetermined condition in such a manner that each of elements in second tabulation data Vdoes not become a negative value, thereby generating third series data W; a second conversion section 15 for applying second linear conversion that is inverse conversion of the first linear conversion, to the third series data W, to generate the second tabulation data V; and an output section 16 for outputting the second tabulation data V.