Tightly Secure Lattice Identity-Based Signature in the Quantum Random Oracle Model

Abstract. We present a quantumly secure identity-based signature

scheme based on the standard short integer solution problem, featuring tight security reductions in the quantum and classic random oracle

models. The scheme has short signatures. Each signature contains a single lattice vector plus a single bit. Compared to the existing tightly

secure, short lattice identity-based signature schemes by Pan and Wagner (PQCrypto’21), our scheme has a shorter signature size (around 30%

shorter), stronger unforgeability, relies on a weaker assumption, and has

detailed proof in the quantum random oracle model.

Keywords: Identity-based signature · strong unforgeability · lattice · quantum random oracle model