A Maliciously-Secure Post-Quantum OPRF from Crypto Dark Matter

We construct protocols for oblivious pseudorandom functions (OPRFs) based on alternating moduli assumptions in the 'Crypto Dark Matter' paradigm (Boneh et al, TCC 2016). Prior OPRFs based on this type of assumption were only secure against a semi-honest adversary. We show how to obtain maliciously secure protocols, by leveraging new cut-and-choose techniques for generating correlated randomness based on vector oblivious linear evaluation (VOLE), which allow efficient conversions between different moduli in zero-knowledge and secure two-party computation. Compared with the state-of-the-art GOLD OPRF (Yang et al, S&P 2025), our construction has a faster online phase in all settings, as well as overall better efficiency in the small-batch setting. Furthermore, our construction supports obtaining a secret-shared output, and can be extended to handle secretshared inputs. This opens up additional applications in variants of private set intersection and secure database operations.