Abstract: A method and apparatus for privately retrieving information from a single electronic storage device (e.g., a database) is described. An inquiring processor identifies a portion of a database memory with information for retrieval and encodes address of the information into a preselected mathematical function that conceals the identity of the selected information from the database. The inquiring processor transmits the encoded function to the database. The database cooperates by executing the encoded function on the database and transmits an encoded result that represents an evaluation of the encoded function to the inquiring processor. The inquiring processor, having knowledge of the selected mathematical function, decodes the encoded result to generate the information from the selected memory section of the database. The inquiry can be repeated until the inquiring processor can retrieve the selected information.

Abstract: Method for retrieving data from a database, while assuring privacy, which comprises providing a database address for the data sought to be retrieved, generating at least two messages and communicating them to two or more database copies, generating two replies from the database copies, wherein one or more of said messages depends on the database address, a pseudo random or random number and wherein each reply depends on the message transmitted to the specific database copy, and the retrieved data is calculated as a function of said replies.