A (t, n) Threshold Digital Signature Scheme with Ability to Identify Cheaters

Based on the security mechanism of the discrete logarithm, an ElGamal-like (t, n) threshold digital signature scheme with ability to identify cheaters is proposed in this paper. In the key generation phase, each participants public and private keys, and the group public key are negotiated among all the participants with no trusted party required. In the signature generation phase, no secure communication is needed between any two participants. This scheme provides the capability of detecting cheating and identifying the cheater that may be from the internal legal participants or the external attackers. The security of this scheme is based on the difficulty of solving the discrete logarithm problem. Analyses show that this scheme is a computationally secure and efficient scheme.