Cerberus vs Other BFT Protocols

Overview

This page compares a specification against deployed protocols, which is the first thing to hold in mind: Cerberus's distinguishing feature – atomic consensus across arbitrary sets of shards – is specified in a peer-reviewed paper but has never run in production.

Traditional BFT (PBFT, HotStuff, Tendermint)

These protocols achieve consensus within a single group of validators. They do not natively support cross-shard atomicity – any sharded system using them requires additional coordination layers that compromise either composability or performance.

Cerberus Braiding, as Specified

Cerberus forms dynamic consensus groups per transaction, braiding across exactly the shards each transaction touches, with a 3-phase commit protocol (pre-prepare, prepare, commit) ensuring atomicity. The whitepaper provides formal safety proofs for this design.

What the Xi'an Candidate Does Instead

Braiding has never run in production. Babylon runs Cerberus unsharded, where there is nothing to braid; the Radix Foundation's Hyperscale implementation, according to the lead developer of the Xi'an candidate, "never really used Cerberus"; and on 2 August 2026 he added that the original Java Hyperscale did not braid either – Dan Hughes having replaced it with an execution process asynchronous to consensus, which hyperscale-rs continues. The stated objection is liveness contagion: braiding makes shards co-dependent for liveness, so a single stalled shard can impede others, whereas asynchronous execution lets a down counterparty shard time out only the transactions that touch it.

The hyperscale-rs candidate reaches cross-shard atomicity differently: one HotStuff-2–derived two-chain commit per shard, a leaderless beacon chain as the control plane, and settlement by exchanged proofs of execution rather than by any vote between shards. A transaction commits only if every participating shard reports success; one abort anywhere is terminal. On its own account this is closer to the deterministic-database tradition than to either braiding or two-phase commit.

The 500k TPS test is often cited as validating braiding in practice. It measured the Radix Foundation's Hyperscale implementation, which per the Xi'an candidate's lead developer "never really used Cerberus".