In 2001, Rivest et al. rstly introduced the concept of ring signatures. A ring signature is a simplied group signature without any manager. It protects the anonymity of a signer. The rst scheme proposed by Rivest et al. was based on RSA cryptosystem and certicate based public key setting. The rst ring signature scheme based on DLP was proposed by Abe, Ohkubo, and Suzuki. Their scheme is also based on the general certicate-based public key setting too. In 2002, Zhang and Kim proposed a new ID-based ring signature scheme using pairings. Later Lin and Wu proposed a more ecient ID-based ring signature scheme. Both these schemes have some inconsistency in computational aspect. In this paper we propose a new ID-based ring signature scheme and a proxy ring signature scheme. Both the schemes are more ecient than existing one. These schemes also take care of the inconsistencies in above two schemes.
Amit K. Awasthi, Sunder Lal