Safety (Consensus)
A consensus property guaranteeing the network never finalizes two conflicting, contradictory versions of the truth.
Safety is a consensus property guaranteeing that a network never finalizes two conflicting, contradictory versions of its history or state — once something is genuinely finalized, it stays finalized, and the network never ends up in a state where two different, incompatible outcomes are both treated as settled truth.
Safety is one of two core properties consensus researchers generally evaluate a system against, alongside liveness (see Kaavon's "Liveness (Consensus)" glossary definition) — a consensus design that sacrifices safety under adverse conditions risks a genuinely serious outcome (a chain split into two conflicting "true" versions), which is why most designs prioritize preserving safety even at the cost of temporarily halting progress.
Examples
- A network maintaining safety never finalizes two conflicting versions of its history, even under adverse conditions.
- Most consensus designs prioritize preserving safety over liveness under extreme adverse conditions, since a safety failure risks a genuinely serious, conflicting chain split.