ANONYMIZATION SYSTEM AND ANONYMIZATION METHOD

To verify the correctness of anonymization processing on a data group even after the anonymization processing is performed on pieces of data in the data group.SOLUTION: A first apparatus creates a second hash value of a plurality of data groups different in attribute based on a first hash value of pieces of data in the plurality of data groups. A second apparatus creates a first hash value of pieces of data in a data group with a specific attribute in response to an anonymization request from a third apparatus. As a result of transmitting the anonymization request for the data group with the specific attribute to the second apparatus, the third apparatus acquires the first hash value of the pieces of data in the data group with the specific attribute, a data group with a residual attribute excluding the data group with the specific attribute, and the second hash value, creates a third hash value based on the first hash value of the pieces of data in the data group with the residual attribute and the first hash value of the pieces of data in the data group with the specific attribute, and verifies the correctness of anonymization processing by using the second hash value and the third hash value.SELECTED DRAWING: Figure 10 【課題】データ群のデータに匿名化処理を施した後でも、データ群に対する匿名化処理の正当性を検証すること。【解決手段】第１装置が、属性が異なる複数のデータ群の各々のデータの第１ハッシュ値に基づいて複数のデータ群の第２ハッシュ値を生成し、第２装置が、第３装置からの匿名化要求により特定の属性のデータ群の各々のデータの第１ハッシュ値を生成し、第３装置が、特定の属性のデータ群の匿名化要求を第２装置に送信した結果、特定の属性のデータ群の各々のデータの第１ハッシュ値と、特定の属性のデータ群の除く残余の属性のデータ群と、第２ハッシュ値と、を取得し、残余の属性のデータ群の各々のデータの第１ハッシュ値と特定の属性のデータ群の各々のデータの第１ハッシュ値とに基づいて第３ハッシュ値を生成し、第２ハッシュ値と第３ハッシュ値とで匿名化処理の正当性を検証する。【選択図】図１０