Additive zero-knowledge and applications: spam prevention

In this paper, we introduce the concept of additive zero knowledge. Essentially, an additive proof can be considered as a proof system involving many provers and one verifier such that the statements of all the provers are proved simultaneously. Our model of additive proofs is presented using constructions of blind group identification, aggregate signatures and chained signatures. The security of our protocols relies on the difficulty of the underlying Diffie-Hellman problem in bilinear maps. As applications, we present a novel method to prevent spam.