Post-Quantum Traceable Anonymous Credentials from Lattices
Madusha Chathurangi, Qinyi Li, Ernest Foo, Leo Yu Zhang · IACR Communications in Cryptology · 2026
Traceable Anonymous Credentials (TACs) are an important extension of Anonymous Credentials (ACs). TAC systems protect user privacy during credential verifications while also allowing for the de-anonymization of credentials in cases of misbehavior. Although TACs have been studied with several constructions based on number-theoretic assumptions, the formal security definitions of credential tracing and efficient constructions with post-quantum security remain absent. This work addresses both gaps by presenting the first formalization of TACs and the first post-quantum construction based on module lattices. We design a new trapdoor for a lattice-based commitment, which allows partial recovery of commitment randomness. We integrate our trapdoor commitment into the state-of-the-art lattice-based AC system by Jeudy et al. (Crypto 2023) to derive our efficient TAC system.