INTERMEDIATE SERVER, DATABASE QUERY PROCESSING METHOD AND PROGRAM

To make it possible to prevent leakage of sensitive information from a database without using a server having both secure operation management and a high database operation processing capability. An intermediate server includes: a cryptography processing unit that encrypts or decrypts data stored in a database; a query conversion unit that converts a query to the database into a first query that does not need processing by the cryptography processing unit and a second query that needs the processing by the cryptography processing unit; and a query processing unit that sends the first query to a database server connected to the database to acquire a result from the database server, and executes the second query using the cryptography processing unit.