Paper 2018/319

HydRand: Practical Continuous Distributed Randomness

Philipp Schindler, Aljosha Judmayer, Nicholas Stifter, and Edgar Weippl


A reliable source of randomness is not only an essential building block in various cryptographic, security, and distributed systems protocols, but also plays an integral part in the design of many new blockchain proposals. Consequently, the topic of publicly-verifiable, bias-resistant and unpredictable randomness has recently enjoyed increased attention. In particular random beacon protocols, aimed at continuous operation, can be a vital component for current Proof-of-Stake based distributed ledger proposals. We improve upon previous random beacon approaches with HydRand, a novel distributed protocol based on publicly-verifiable secret sharing (PVSS) to ensure unpredictability, bias-resistance, and public-verifiability of a continuous sequence of random beacon values. Furthermore, HydRand provides guaranteed output delivery of randomness at regular and predictable intervals in the presence of adversarial behavior and does not rely on a trusted dealer for the initial setup. Compared to existing PVSS based approaches that strive to achieve similar properties, our solution improves scalability by lowering the communication complexity from $ \mathcal{O}(n^3) $ to $ \mathcal{O}(n^2) $. Furthermore, we are the first to present a detailed comparison of recently described schemes and protocols that can be used for implementing random beacons.

Available format(s)
Cryptographic protocols
Publication info
Published elsewhere. Minor revision. to appear in: Proceedings of the 2020 IEEE Symposium on Security and Privacy
distributed randomnessrandomness beaconByzantine agreement
Contact author(s)
pschindler @ sba-research org
2019-07-30: last of 4 revisions
2018-04-04: received
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Creative Commons Attribution


      author = {Philipp Schindler and Aljosha Judmayer and Nicholas Stifter and Edgar Weippl},
      title = {{HydRand}: Practical Continuous Distributed Randomness},
      howpublished = {Cryptology ePrint Archive, Paper 2018/319},
      year = {2018},
      note = {\url{}},
      url = {}
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