Practical, Round-Optimal Lattice-Based Blind Signatures

In this video we talk about our construction of the first overall practical, lattice based blind signature which supports unbounded number of signature queries and is also round-optimal. Our construction is based on digital signature scheme by Gentry, Peikert and Vaikuntanathan [STOC'08] and NIZK proof system for linear statements with small unknowns, which are significantly more efficient than their general-purpose counterparts. The security of our scheme is based on a new assumption that we introduce, called one-more-ISIS. This assumption can be seen as a lattice analogue of the one-more-RSA assumption by Bellare et al [JoC'03], that was introduced to construct efficient round-optimal blind signature in the number theoretic regime. We provide a detailed cryptanalysis of our assumption and an estimate of our parameters in the paper.