In a database query operation, a quantum private query (QPQ) protocol allows a user to determine whether the database provider has been trying to obtain information about their query by performing quantum superpositions of different queries in addition to performing normal queries. This means that, in addition to being able to request the jth or the kth records in the database, the user can also request both records in a quantum superposition. To find out whether the database provider is trying to discover her queries, the user sends proper superpositions of queries and then checks the answer provided by the database to determine whether the superposition has been preserved. If superposition has not been preserved, the user can be confident that the database provider has cheated, and has tried to obtain information on the query.