Paper 2025/675 Original: eprint.iacr.org/2025/675 ↗

Trilithium: Efficient and Universally Composable Distributed ML-DSA Signing

Abstract

In this paper, we present Trilithium: a protocol for distributed key generation and signing compliant with FIPS 204 (ML-DSA). Our protocol allows two parties, ``server'' and ``phone'' with assistance of correlated randomness provider (CRP) to produce a standard ML-DSA signature. We prove our protocol to be secure against a malicious server or phone in the universal composability model, introducing some novel techniques to argue the security of two-party secure computation protocols with active security against one party, but only active privacy against the other. We provide an implementation of our protocol in Rust and benchmark it, showing the practicality of the protocol. As additional contribution, we propose an actively secure generalization of Attrapadung et al. (ASIA CCS ’22) comparison protocol and a new rounding protocol for fractions with private numerator.