A New Strong Proactive Verifiable Secret Sharing Scheme with Unconditional Security

Abstract

In secret sharing scheme, the master secret and all the private shares (which are distributed by the dealer to the shareholders) are the two secrets which are to be maintained confidentially. In all the secret sharing schemes proposed till date, private shares are reused to reconstruct the master secret. But we proposed a new way of Proactive Secret Sharing Scheme in which, instead of renewing the private shares frequently at the beginning of each timeslot during the share renewal process, each time master secret is renewed. In this way private shares can be reused for a longer period of time and to construct different master secrets. In addition, after each renewing process, shareholders can work together to verify that their private shares are consistent without revealing private shares. We also proposed protocols to generate and renew master secret, authenticate public shares of the master secret, add or revoke shares and change threshold of the master secret. Thus an enhancement to Proactive Secret Sharing is proposed in this thesis and this unique feature simples the implementation of PSS as the change is to be made only to the master secret (central server) without effecting all private shares.