Threshold signature scheme with subliminal channel

Threshold signature is an important signature with additional property; it can achieve effective supervision on signature generating and signature verifying. This paper analyzed the basic principles of threshold cryptosystem and its superiority for application in threshold signature schemes. Considering the security threats and system flaws of present signature schemes, we present a threshold signature scheme based on elliptic curves cryptosystem. The scheme achieves threshold generating and verifying of signature by utilizing secret sharing in signature processing, and it also achieves threshold management of identity tracing by identity blinding and probabilistic encryption algorithms. As security proof for the scheme, we present a typical subliminal channel scheme for the threshold signature. The subliminal message can only be generated and recovered by no less than t valid members; so the subliminal channel renders effective supervision on subliminal message and identity secrecy. Further analyses and comparison also justify the brevity, security and high efficiency of the scheme.