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.

Abstract: A method for reconstructing a secret, over a public communication channel, using a perfect t-out-of-n secret sharing scheme. The scheme having a dealer which utilizes a delivering procedure for privately delivering n secret shares of the secret along with n keys to n participants that are interlinked by the channel. The scheme further having a secret reconstructing procedure for being executed by selected recipient participants, for reconstructing the secret by utilizing self secret share of the recipient participant and l-1 secret shares of the other participants. The secret reconstructing procedure includes the following steps:(i) receiving over said public communication channel l-1 encoded secret shares from the l-1 participants, respectively;(ii) decoding each one of the l-1 encoded secret shares, thereby obtaining l-1 decoded secret shares; and(iii) reconstructing the secret from the l-1 decoded secret shares and from the self secret share of the recipient participant.