Paper 2015/014

Group Signatures from Lattices: Simpler, Tighter, Shorter, Ring-based

San Ling and Khoa Nguyen and Huaxiong Wang

Abstract

We introduce a lattice-based group signature scheme that provides several noticeable improvements over the contemporary ones: simpler construction, weaker hardness assumptions, and shorter sizes of keys and signatures. Moreover, our scheme can be transformed into the ring setting, resulting in a scheme based on ideal lattices, in which the public key and signature both have bit-size soft-O(n log N), for security parameter n, and for group of N users. Towards our goal, we construct a new lattice-based cryptographic tool: a statistical zero-knowledge argument of knowledge of a valid message-signature pair for Boyen's signature scheme (Boyen, PKC'10), which potentially can be used as the building block to design various privacy-enhancing cryptographic constructions.

Note: This is the full version of a paper due to appear at the 18th International Conference on Practice and Theory in Public-Key Cryptography (PKC 2015).