NI-DKG: Non-Interactive Distributed Key Generation Using Blockchain and Zero-Knowledge Proofs

Alex Kampa; Pau Escrich; Marta Bellés-Muñoz; Roger Baig

Paper 2026/552

NI-DKG: Non-Interactive Distributed Key Generation Using Blockchain and Zero-Knowledge Proofs

Alex Kampa

, Vocdoni Association

Pau Escrich, Vocdoni Association

Marta Bellés-Muñoz

, Pompeu Fabra University

Roger Baig

, Polytechnic University of Catalonia

Abstract

We present a non-interactive DKG protocol that eliminates complaint procedures through the systematic use of ZK proofs. The protocol requires a timed public bulletin board with adjoined computing capacity as its coordination layer, a capability realized in practice by smart-contract-enabled blockchains. Existing smart-contract DKGs detect invalid contributions only after submission, requiring dispute phases that introduce timing constraints and attack surfaces. In our protocol, each participant submits a single zk-SNARK proving the correctness of their contribution: polynomial commitment consistency, Feldman verification equations, and correct share encryption. The smart contract rejects any invalid proof, simplifying the protocol to non-interactive phases delimited by block numbers. The protocol relies on standard primitives: Shamir's secret sharing, Feldman commitments, hashed ElGamal encryption, and Chaum-Pedersen discrete-log equality proofs, with on-chain verification via zk-SNARKs. We provide an implementation outline for EVM-compatible chains, including circuit specifications for key generation, threshold decryption, and optional secret key disclosure. We also discuss EVM verifier constraints on the number of public inputs and sketch approaches to address them.

Metadata

Available format(s): PDF
Category: Cryptographic protocols
Publication info: Preprint.
Keywords: Distributed key generation Threshold cryptography Verifiable secret sharing Zero-knowledge proofs Blockchain
Contact author(s): alex @ vocdoni org
pau @ vocdoni org
marta belles @ upf edu
roger baig @ upc edu
History: 2026-03-22: approved; 2026-03-19: received; See all versions
Short URL: https://ia.cr/2026/552
License: CC BY

BibTeX

@misc{cryptoeprint:2026/552,
      author = {Alex Kampa and Pau Escrich and Marta Bellés-Muñoz and Roger Baig},
      title = {{NI}-{DKG}: Non-Interactive Distributed Key Generation Using Blockchain and Zero-Knowledge Proofs},
      howpublished = {Cryptology {ePrint} Archive, Paper 2026/552},
      year = {2026},
      url = {https://eprint.iacr.org/2026/552}
}