A Framework for Practical Anonymous Credentials from Lattices
Ngoc Khanh Nguyen
Abstract:
We present a framework for building practical anonymous credential schemes based on the hardness of lattice problems. The running time of the prover and verifier is independent of the number of users and linear in the number of attributes. The security of our scheme is based on a new family of lattice assumptions which roughly states that given short pre-images of random elements in some set S, it is hard to create a pre-image for a fresh element in such a set. We show that if the set admits efficient zero-knowledge proofs of knowledge of a commitment to a set element and its pre-image, then this yields practically-efficient privacy-preserving primitives such as blind signatures, anonymous credentials, and group signatures. We propose a candidate instantiation of a function from this family which allows for such proofs and thus yields practical lattice-based primitives.
Bio:
Ngoc Khanh Nguyen is postdoctoral researcher at EPFL, hosted by Prof. Alessandro Chiesa. His current topics of interests are (but not limited to) lattice-based cryptography and efficient post-quantum zero-knowledge proofs. Previously, he obtained his PhD degree at ETH Zurich and IBM Research Europe - Zurich, supervised by Dr Vadim Lyubashevsky and Prof. Dennis Hofheinz. Before that, he did his undergraduate and master studies at the University of Bristol, UK.