How to leak a secret from multiple sources

A (t, n) threshold ring signature, introduced by Bresson et al., allows a group of t members to leak a secret anonymously. Threshold ring signature schemes are desirable for ad-hoc groups such as mobile ad-hoc networks. In this paper, we first point out that the construction of threshold ring signature is very inefficient when t is small comparing to n. Next, a generalized (t, n) threshold signature scheme is first proposed in literature through a linear equation system with t equations but n variables. The proposed generalized threshold signature is linkable and convertible. Our generalized construction is unconditionally signer-ambiguous, provable secure in random oracle model and exceptionally efficient.