A Blind Ring Signature Based on the Short Integer Solution Problem A blind ring signature scheme is a combination of a ring signature and a blind signature, which allows not only any member of a group of signers to sign on a message on behalf of the group without revealing its identity but also the user who possesses the message to blind it before sending to the group to be signed. Blind ring signature schemes are essential components in ecommercial, evoting etc. In this paper, we propose the first blind ring signature scheme based on lattices. More precisely, our proposed scheme is proven to be secure in random oracle model under the hardness of the short integer solution (SIS) problem.

Scalable Revocable IdentityBased Signature Scheme with Signing Key Exposure Resistance from Lattices In 2014, a new security definition of a revocable identitybased signature (RIBS) with signing key exposure resistance was introduced. Based on this new definition, many scalable RIBS schemes with signing key exposure resistance were proposed. However, the security of these schemes is based on traditional complexity assumption, which is not secure against attacks in the quantum era. Latticebased cryptography has many attractive features, and it is believed to be secure against quantum computing attacks. We reviewed existing latticebased RIBS schemes and found that all these schemes are vulnerable to signing key exposure. Hence, in this paper, we propose the first latticebased RIBS scheme with signing key exposure resistance by using the leftright lattices and delegation technology. In addition, we employ a complete subtree revocation method to ensure our construction meeting scalability. Finally, we prove that our RIBS scheme is selectiveID existentially unforgeable against chosen message attacks (EUFsIDCMA) under the standard short integer solutions (SIS) assumption in the random oracle model.