Paper 2023/1554

Cornucopia: Distributed randomness beacons at scale

Miranda Christ, Columbia University
Kevin Choi, New York University
Joseph Bonneau, New York University, a16z crypto research

We propose Cornucopia, a distributed randomness beacon protocol combining accumulators and verifiable delay functions. Cornucopia extends the Unicorn protocol of Lenstra and Wesolowski, utilizing an accumulator to enable efficient verification by each participant that their randomness contribution has been included in the beacon output. The output is unpredictable as long as at least one participant is honest, yielding a highly scalable distributed randomness beacon with strong security properties. The security of this construction reduces to a novel property of accumulators, insertion security. We first show that not all accumulators are insertion-secure. We then prove that common constructions (Merkle trees, RSA accumulators, and bilinear accumulators) are either naturally insertion-secure or can be made so with trivial modifications. Finally, we give two generic constructions for insertion-secure accumulators, from universal accumulators and vector commitments respectively.

Available format(s)
Cryptographic protocols
Publication info
randomness beacondistributed randomnessblockchainverifiable delay functionaccumulator
Contact author(s)
mchrist @ cs columbia edu
kevin choi @ nyu edu
jcb @ cs nyu edu
2024-01-31: revised
2023-10-10: received
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Creative Commons Attribution


      author = {Miranda Christ and Kevin Choi and Joseph Bonneau},
      title = {Cornucopia: Distributed randomness beacons at scale},
      howpublished = {Cryptology ePrint Archive, Paper 2023/1554},
      year = {2023},
      note = {\url{}},
      url = {}
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