Privacy-protected data aggregation device and privacy-protected data aggregation system

Abstract

A privacy-protected data aggregation device () includes: an attribute information encryption unit () that encrypts attribute information in user data to be aggregated, which includes a plurality of pieces of attribute information, using a homomorphic encryption method enabling aggregation processing; an aggregation processing unit () that aggregates user data with encrypted attribute information, for all combinations of possible values of the plurality of pieces of attribute information in domain data that defines possible values of each of the pieces of attribute information included in the user data, to obtain aggregated data including an aggregation result and encrypted attribute information; an anonymization processing unit () that performs anonymization processing on the aggregated data; and a decryption unit () that decrypts aggregated data subjected to the anonymization processing to obtain aggregated data including an aggregation result after the anonymization processing and decrypted attribute information.