SBFT

SBFT stands for Scalable Byzantine Fault Tolerance. It is a consensus protocol designed for permissioned distributed systems and blockchain-like applications where some nodes may act maliciously. The protocol aims to deliver safety (agreement on the same sequence of operations) and liveness (progress despite faults) in networks that can be partially synchronous and contain Byzantine faults.

Key features of SBFT include the use of threshold cryptography to reduce the size of inter-node communications, batching of multiple transactions to improve throughput, and view changes with leader rotation to maintain progress when a leader misbehaves. SBFT is designed to scale beyond traditional Byzantine fault-tolerant schemes by optimizing communication patterns and enabling efficient reconfiguration to accommodate larger networks.

In terms of operation, SBFT coordinates a group of nodes to agree on a sequence of requests. It employs a multi-round exchange that produces certificates or commits for decided batches, often leveraging threshold signatures to compress the final proofs that attest to agreement. The protocol supports dynamic membership to handle node additions or removals and is typically implemented in a partially synchronous network model, where time bounds are not guaranteed but eventual agreement is possible under reasonable delays.

SBFT is commonly used in permissioned blockchain environments and enterprise-grade distributed ledgers that require strong resilience to Byzantine faults while maintaining high throughput. It is related to other BFT protocols such as PBFT but emphasizes scalability and efficiency for larger node sets. Limitations include added cryptographic complexity and the need for careful deployment to ensure optimal performance.