Paper 2026/847

Lattice Group Signatures, Revisited

Pierre-Alain Fouque, Univ Rennes, Inria, CNRS, IRISA

Corentin Jeudy, Orange (France)

Olivier Sanders, Orange (France)

Abstract

Group signatures are one of the central privacy-preserving authentication mechanisms, offering an interesting trade-off between accountability and anonymity. Their versatility has led to many applications and even standardization at ISO/IEC. Unfortunately, they lack so far efficient quantum-safe constructions, despite several works implementing the seminal framework by Bellare, Micciancio and Warinschi (BMW) in the lattice setting. In this work, we propose an alternative lattice-based construction that departs from the BMW blueprint by trying to minimize the number of elements to conceal in zero-knowledge proofs, the latter being quite complex in this setting. Concretely, it relies on delegated lattice bases, while avoiding the complex OR-proofs of some previous attempts in that direction. Combined with some tricks leveraging the peculiarities of a recent lattice sampler, it results in an efficient scheme that yet retains all the BMW security properties while only relying on standard lattice assumptions.

@misc{cryptoeprint:2026/847,
      author = {Paul Delhom and Pierre-Alain Fouque and Corentin Jeudy and Olivier Sanders},
      title = {Lattice Group Signatures, Revisited},
      howpublished = {Cryptology {ePrint} Archive, Paper 2026/847},
      year = {2026},
      url = {https://eprint.iacr.org/2026/847}
}