1. A method for querying a database implemented with a quantum random access memory, the method ensuring complete data privacy and allowing a user to determine whether the database provider has been trying to obtain information about a query and comprising: (a) preparing by the user a first register containing a desired query and a second register containing the quantum superposition of the desired query with another query; (b) selecting at random one of the first and second registers and presenting the selected register to the database provider; (c) receiving a first response to the register selected in step (b) and sending the register not selected in step (b) to the database provider; (d) receiving a second response to the register sent in step (c); (e) measuring the response to the register containing the desired query to obtain an answer to the query; and (f) measuring the response to the register containing the superposition to determine whether the database provider has been trying to obtain information about the desired query.