Lecture Notes in Computer Science vol:2551 pages:395-408
INDOCRYPT 2002 date:December 16-18, 2002
This work is about distributed protocols for oblivious transfer, proposed by Naor and Pinkas, and recently generalized by Blundo et. al. In this settings a Sender has n secrets and a Receiver is interested in one of them. The Sender distributes the information about the secrets to m servers, and a Receiver must contact a threshold of the servers in order to compute the secret. These distributed oblivious transfer protocols provide information theoretic security. We present impossibility result and lower bound for existence of one-round threshold distributed oblivious transfer protocols, generalizing the results of Blundo et. al. A threshold based construction implementing 1-out-of-n distributed oblivious transfer achieving the proved lower bound for existence is proposed. A condition for existence of general access structure distributed oblivious transfer scheme is proven. We also present a general access structure protocol implementing 1-out-of-n distributed oblivious transfer.