The basic motivation for Private Information Retrieval is a family of two-party protocols in which one of the parties (the "sender") owns a database, and the other part (the "receiver") wants to query it with certain privacy restrictions and warranties. So, as a result of the protocol, if the "receiver" wants the "i-th" value in the database he must learn the "i-th" entry, but the "sender" must learn nothing about "i". In a general PIR protocol, a computationally unbounded "sender" can learn nothing about "i" so privacy is theoretically preserved. Since the PIR problem was posed, different approaches to its solution have been pursued and some variations were proposed.