Paper 2016/889

Ouroboros: A Provably Secure Proof-of-Stake Blockchain Protocol

Aggelos Kiayias, Alexander Russell, Bernardo David, and Roman Oliynykov


We present ``Ouroboros,'' the first blockchain protocol based on proof of stake with rigorous security guarantees. We establish security properties for the protocol comparable to those achieved by the bitcoin blockchain protocol. As the protocol provides a ``proof of stake'' blockchain discipline, it offers qualitative efficiency advantages over blockchains based on proof of physical resources (e.g., proof of work). We also present a novel reward mechanism for incentivizing proof of stake protocols and we prove that, given this mechanism, honest behavior is an approximate Nash equilibrium, thus neutralizing attacks such as selfish mining. We also present initial evidence of the practicality of our protocol in real world settings by providing experimental results on transaction confirmation and processing.

Note: various minor corrections in the previous major revision.

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Publication info
A major revision of an IACR publication in Crypto 2017
blockchainconsensusproof of stake.
Contact author(s)
akiayias @ inf ed ac uk
2019-07-20: last of 8 revisions
2016-09-14: received
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      author = {Aggelos Kiayias and Alexander Russell and Bernardo David and Roman Oliynykov},
      title = {Ouroboros: A Provably Secure Proof-of-Stake Blockchain Protocol},
      howpublished = {Cryptology ePrint Archive, Paper 2016/889},
      year = {2016},
      note = {\url{}},
      url = {}
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