Definition
Plain language
A classic recipe for getting many computers to agree on a value even when some of them fail or messages arrive out of order.
As stated in the literature
A foundational distributed-consensus protocol for agreeing on a single value under crash failures and message reordering; IronFleet provides a machine-checked verified implementation of it.
Why it matters: Reliable agreement among unreliable machines is the backbone of databases and cloud services that must stay consistent despite failures.
For example, several servers using Paxos can agree on which transaction came first even if one server crashes mid-vote and some messages arrive late.