[[2308.16902] Accountable Safety Implies Finality](https://arxiv.org/abs/2308.16902) ## Abstract Two desired traits are studied for BFT SMR consensus protocols: 1. *Finality:* the protocol retains consistency as long as less than a certain fraction of validators are malicious 1. Even in partially synchronous environments that allow for temporary violations of assumed network delay bounds 2. *Accountable Safety:* In any case of inconsistency, a certain fraction of validators can be identified to have provably violated the protocol ## Intro ### Consensus Purpose of consensus is for a set of parties to reach agreement on how to sequence incoming txs into a linear order called aledger ### Finality Extended in twodirections Some early consensus protocls assume network comms always obey a known delay upper-bound Later construction added temporary network delay-bound violations (partial synchrony) We want to know who violates rule so they can be punished Some protocols provide finality but not accountable safety ### Main Result Accountable safety implies finality If there exists a strat that leads to a safety violation under partial synchrony, then there exists a strat that leads to a safety violation but not enough adversary parties can be identified as protocol violations The more constraints there are on network delays, the easier it is for a protocol to guarantee accountable safety