The (Red)ETA project (η-project) presents a complete set of threshold cryptographic algorithms for Elliptic-Curve Digital Signature Schemes. The submission includes η-keygen, an enhanced decentralized key generation protocol with support for extensibility, refreshability, and general monotone access structures, along with threshold signing algorithms η-Schnorr, η-EdDSA, and η-ECDSA.

Resources

Specification

Team

Alessandro Barenghi
Polytechnic University of Milan

Michele Battagliola
Marche Polytechnic University

Riccardo Longo
Fondazione Bruno Kessler

Alessio Meneghetti
University of Bari Aldo Moro

Gerardo Pelosi
Polytechnic University of Milan

Edoardo Signorini
Telsy SpA

Literature

Tighter Control for Distributed Key Generation: Share Refreshing and Expressive Reconstruction Policies
Riccardo Longo, Alessio Meneghetti, Sara Montanari
Cryptology ePrint Archive, 2025

Extensible Decentralized Secret Sharing and Application to Schnorr Signatures
Michele Battagliola, Riccardo Longo, Alessio Meneghetti
Designs, Codes and Cryptography, 2025

Provably Unforgeable Threshold EdDSA with an Offline Participant and Trustless Setup
Michele Battagliola, Riccardo Longo, Alessio Meneghetti, Massimiliano Sala
Mediterranean Journal of Mathematics, 2023

A Provably-Unforgeable Threshold Schnorr Signature with an Offline Recovery Party
Michele Battagliola, Alessio Galli, Riccardo Longo, Alessio Meneghetti CEUR Workshop Proceedings, 2022

Threshold ECDSA with an Offline Recovery Party
Michele Battagliola, Riccardo Longo, Alessio Meneghetti, Massimiliano Sala
Mediterranean Journal of Mathematics, 2021