Cerberus (BFT) Algorithm | cryptocurrencies, blockchains & live prices

Cerberus is a Byzantine Fault Tolerant consensus protocol developed for the Radix DLT network, designed specifically to support atomic transactions across a massively sharded state space. Cerberus uses a braided approach to consensus where each shard (corresponding to a portion of the global state) has its own local consensus process. When a transaction touches multiple shards, Cerberus braids the consensus of those specific shards together, creating a temporary cross-shard consensus group for just that transaction. This avoids the need for a global ordering of all transactions while still ensuring atomicity — either the entire cross-shard transaction commits across all involved shards, or it is entirely aborted.

The braided consensus approach gives Cerberus theoretically unlimited parallelism for non-overlapping transactions, since transactions touching different state subsets can be processed concurrently without any coordination. This is in contrast to sharding designs that use sequential cross-shard messaging or require all shards to periodically synchronize. Each individual consensus instance uses a three-phase BFT commit protocol. The protocol is designed to maintain both safety and liveness under partial synchrony assumptions, tolerating up to one-third Byzantine validators within each consensus group. The key innovation is that the cross-shard coordination happens at the transaction level rather than the block level, enabling fine-grained parallelism.

Cerberus powers the Radix network, which launched its Babylon mainnet upgrade in September 2023 with smart contract capabilities via Scrypto (a Rust-based language). Radix was founded by Dan Hughes and positions itself as a DeFi-focused Layer 1 blockchain. The Cerberus consensus design was published in a whitepaper and represents Radix's approach to the scalability trilemma — achieving parallelism through fine-grained sharding while maintaining atomic composability, which is particularly important for DeFi applications where transactions frequently interact with multiple smart contracts. The full vision of Cerberus with dynamic, transaction-level sharding is being implemented progressively as the network matures.