US Patent 8725651 System and method for providing private demand-driven pricing

A system and method for providing private demand-driven pricing for fixed cost digital goods are described. An encrypted price of identically-priced digital goods is additively perturbed. The digital goods are stored in a database by a seller system and an approximate revenue maximizing price for the digital goods has not been realized. A purchasing decision about one of the digital goods based upon the additively-perturbed price is sent to the seller system without revealing the particular digital good. A conditionally disclosed symmetric key is received in return under which the digital goods in the database have been encrypted. The purchaser system and seller system engage in symmetric private information retrieval on the database. The purchaser system decrypts the digital good purchased with the symmetric key. The seller system privately updates the encrypted price of the digital goods to close on the approximate revenue maximizing price whenever a purchase is made.