Efficient AttributeBased Ring Signature Schemes

Two new attribute-based ring signature schemes are proposed in this paper. The signer can sign message with parts of its attribute. All users that possess these attributes can form a ring. Anyone out of this ring could not forge the signature on behalf of the ring. The first one is existentially unforgeable against selective attributes attacks in the random oracle model and the second construction is existentially unforgeable against selective attributes attacks in the standard model. Both schemes in this paper rest on the hardness of the computational Diffie-Hellman in tractability assumption. For anonymity, it requires that the signer is anonymous among the users with the same attributes for signature, even for the attribute center. In attribute-based ring signature scheme the signer need not know who are involved in this ring, so these new schemes are more efficient and flexible than the previous identity-based ring signature schemes. Compared with the existing attribute-based ring signature scheme, the size of the signature decreases by 1/3, and the pairing operations in our schemes also decrease by 1/3. Thus new schemes are more efficient in the communication cost and the computational cost. Attribute-based ring signature is useful in many important applications such as anonymous authentication and attribute-based messaging systems.