Key Features

• Evolution and Background: AptosBFT evolved from the DiemBFT protocol, originally developed for the Diem project, and has undergone several iterations. The current version, AptosBFTv4, is based on Jolteon, which improves upon the HotStuff protocol by reducing latency by 50% through a pBFT-style quadratic view change 3.
• Modular Architecture: Aptos employs a modular approach to transaction processing, which includes transaction dissemination, block metadata ordering, parallel transaction execution, batch storage, and ledger certification. This architecture supports frequent and instant protocol upgrades with minimal interruption .
• Quorum Store: This intermediary phase between the mempool and consensus protocols helps increase transaction throughput by 12x in a consensus-only test and 3x in an end-to-end test. It orders transactions into batches based on gas fees and broadcasts them to validators, ensuring availability and uniqueness 3.
• Parallel Execution: Aptos uses a parallel execution engine called Block-STM, which allows for optimistic concurrency control and dynamic parallelism, enhancing performance and scalability 3.
• Future Developments: Aptos is exploring new consensus mechanisms like Shoal, which combines Directed Acyclic Graph (DAG) and BFT qualities to further reduce latency and increase throughput 56.

Recent Developments

• Consensus Observer (CO): A new data dissemination technique called Consensus Observer has been implemented to enhance block synchronization and reduce transaction latencies. This allows for immediate block propagation, enabling full nodes to process blocks in parallel with validators 78.