Anonymization apparatus, anonymization method, and program

An anonymization method comprising:

• an overlapping exclusion step of an anonymization apparatus generating a partial table of M×L including L records of a table to be anonymized which have sets of values of p master attributes different from each other, from the table to be anonymized of M×N, where M is an integer equal to or greater than 2 representing a number of attributes, N is an integer equal to or greater than 1 representing a number of records, p is an integer equal to or greater than 1 and equal to or less than M representing a number of master attributes, and L is an integer equal to or greater than 1 and equal to or less than N representing a number of sets of values of the p master attributes which are different from each other;
• an anonymization step of the anonymization apparatus generating an anonymized partial table of M×L from the partial table by anonymizing the p master attributes in the partial table;
• and
• an overlapping restoration step of the anonymization apparatus generating an anonymized table of M×N from the table to be anonymized and the anonymized partial table by anonymizing the p master attributes in the table to be anonymized.