Safe Permissionless Consensus

Youer Pu, Lorenzo Alvisi, Ittay Eyal

Research output: Other contributionpeer-review


Nakamoto's consensus protocol works in a permissionless model, where nodes can join and leave without notice.
However, it guarantees agreement only probabilistically.
Is this weaker guarantee a necessary concession to the severe demands of supporting a permissionless model?
This paper shows that, at least in a benign failure model, it is not. It presents Sandglass, the first permissionless consensus algorithm that guarantees deterministic agreement and termination with probability 1 under general omission failures.
Like Nakamoto, Sandglass adopts a hybrid synchronous communication model, where, at all times, a majority of nodes (though their number is unknown) are correct and synchronously connected, and allows nodes to join and leave at any time.
Original languageEnglish
StatePublished - 2022


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