A New, Publicly Verifiable, Secret Sharing Scheme

A publicly verifiable secret sharing (pvss) scheme, as introduced by stadler, has a feature where anyone, besides the participants, can verify the validity of the shares distributed by the dealer. schoenmakers added a new feature, by providing a proof of correctness of the shares released by the players in the reconstruction process. this protocol is claimed to be an improvement on stadier's and fujisaki-okamoto's, both in efficiency and in the type of intractability assumptions. however, young-yung improved schoenmakers' pvss, using a discrete-log instead of a decision diffie-hellman. in this paper, a new pvss is presented, having an intrinsic difference with its predecessors, that is, the participants can prove the validity of their given shares, implicitly, proving their membership by a zero-knowledge protocol. this feature prevents cheaters from participating in the reconstruction process to gain valid shares. hence, the new proposed pvss is more secure than previous ones. besides, the dealer only sends the amount of commitments limited to the threshold value, regardless of the number of shareholders; this leads to a more dynamic protocol.