Ouroboros praos: An adaptively-secure, semi-synchronous proof-of-stake blockchain
Advances in Cryptology–EUROCRYPT 2018: 37th Annual International Conference on …, 2018•Springer
Abstract We present “Ouroboros Praos”, a proof-of-stake blockchain protocol that, for the first
time, provides security against fully-adaptive corruption in the semi-synchronous setting:
Specifically, the adversary can corrupt any participant of a dynamically evolving population
of stakeholders at any moment as long the stakeholder distribution maintains an honest
majority of stake; furthermore, the protocol tolerates an adversarially-controlled message
delivery delay unknown to protocol participants. To achieve these guarantees we formalize …
time, provides security against fully-adaptive corruption in the semi-synchronous setting:
Specifically, the adversary can corrupt any participant of a dynamically evolving population
of stakeholders at any moment as long the stakeholder distribution maintains an honest
majority of stake; furthermore, the protocol tolerates an adversarially-controlled message
delivery delay unknown to protocol participants. To achieve these guarantees we formalize …
Abstract
We present “Ouroboros Praos”, a proof-of-stake blockchain protocol that, for the first time, provides security against fully-adaptive corruption in the semi-synchronous setting: Specifically, the adversary can corrupt any participant of a dynamically evolving population of stakeholders at any moment as long the stakeholder distribution maintains an honest majority of stake; furthermore, the protocol tolerates an adversarially-controlled message delivery delay unknown to protocol participants.
To achieve these guarantees we formalize and realize in the universal composition setting a suitable form of forward secure digital signatures and a new type of verifiable random function that maintains unpredictability under malicious key generation. Our security proof develops a general combinatorial framework for the analysis of semi-synchronous blockchains that may be of independent interest. We prove our protocol secure under standard cryptographic assumptions in the random oracle model.
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