ABSTRACT:

Threshold-multisignature schemes mix the properties of threshold cluster-oriented signature schemes and multisignature schemes to yield a signature scheme that allows a threshold (t) or a lot of group members to collaboratively sign an arbitrary message. In distinction to threshold cluster signatures, the individual signers do not stay anonymous, but are publicly identifiable from the data contained within the valid threshold-multisignature. The main objective of this paper is to propose such a secure and efficient threshold-multisignature theme. The paper uniquely defines the fundamental properties of threshold-multisignature schemes and shows that the proposed theme satisfies these properties and eliminates the latest attacks to that different similar schemes are subject. The efficiency of the proposed theme is analyzed and shown to be superior to its counterparts. The paper additionally proposes a discrete logarithm based distributed-key management infrastructure (DKMI), which consists of a spherical optimal, publicly verifiable, distributed-key generation (DKG) protocol and a 1 spherical, publicly verifiable, distributed-key redistribution/updating (DKRU) protocol. The round optimal DKRU protocol solves a major downside with existing secret redistribution/updating schemes by giving cluster members a mechanism to identify malicious or faulty share holders in the first round, so avoiding multiple protocol executions.