A ring signature scheme based on the Nyberg-Rueppel signature scheme

Ring signature allows to specify a set of possible signers without revealing which member actually produced the signature. This concept was first formalized in 2001 by Rivest, Shamir, and Tauman[3]. Authors of [3] also proposed two versions of ring signature scheme. However, to achieve the goal of anonymity, each user should do much computation in the initial procedure: they should do much work to generate their private and public keys, e.g. in the RSA version, each user should find n(i) such that it is the product of two distinct large prime and compute his private/public keys. Moreover, one should extend the one-way trapdoor functions to a common domain since these functions are computed in different domains. This paper's main contribution is to present a version of ring signature scheme which uses a common modulus. Thus, Our proposed scheme is much more efficient in the setup procedure. Further more, the size of public and private keys are reduced.