zkBeacon: Proven Randomness Beacon based on Zero-knowledge Verifiable Computation

Thomas Lavaur, Thomas Lavaur, Jérôme Lacan

2022

Abstract

The generation of random numbers by a trusted third-party is essential to many cryptographic protocols. Recently, the NIST proposed the standardization of randomness beacons, which are hash-based chains of pulses. Each pulse contains a random number and is generated at regular time intervals. However, if the owner of the beacon generator is untrusted, several attacks allow the manipulation of the provided random numbers. In this paper, we firstly suggest protecting the first hash functions of the NIST scheme by adding a verifiable argument of knowledge. More precisely, we propose furnishing a zk-SNARK or a zk-STARK with the hash to make the system more transparent and resistant to randomness manipulation. Secondly, we propose a verifiable computation-based interactive protocol to allow a client, with the help of the beacon, to generate proven randomness. Then, we show that connecting this system to a blockchain could have several benefits. We provide a security analysis with a model allowing a malicious beacon generator. We prove that our first application improves the resilience of the system against randomness manipulation attacks and that the interactive protocol rules out timing attacks for the client and ensures the non-predictability of the random numbers. Finally, we evaluated the computation cost with zk-SNARKs.

Paper Citation

in Harvard Style

Lavaur T. and Lacan J. (2022). zkBeacon: Proven Randomness Beacon based on Zero-knowledge Verifiable Computation. In Proceedings of the 19th International Conference on Security and Cryptography - Volume 1: SECRYPT, ISBN 978-989-758-590-6, pages 406-414. DOI: 10.5220/0011327500003283

in Bibtex Style

@conference{secrypt22,
author={Thomas Lavaur and Jérôme Lacan},
title={zkBeacon: Proven Randomness Beacon based on Zero-knowledge Verifiable Computation},
booktitle={Proceedings of the 19th International Conference on Security and Cryptography - Volume 1: SECRYPT,},
year={2022},
pages={406-414},
publisher={SciTePress},
organization={INSTICC},
doi={10.5220/0011327500003283},
isbn={978-989-758-590-6},
}

in EndNote Style

TY - CONF

JO - Proceedings of the 19th International Conference on Security and Cryptography - Volume 1: SECRYPT,
TI - zkBeacon: Proven Randomness Beacon based on Zero-knowledge Verifiable Computation
SN - 978-989-758-590-6
AU - Lavaur T.
AU - Lacan J.
PY - 2022
SP - 406
EP - 414
DO - 10.5220/0011327500003283