2 research outputs found
FastPay: High-Performance Byzantine Fault Tolerant Settlement
FastPay allows a set of distributed authorities, some of which are Byzantine,
to maintain a high-integrity and availability settlement system for pre-funded
payments. It can be used to settle payments in a native unit of value
(crypto-currency), or as a financial side-infrastructure to support retail
payments in fiat currencies. FastPay is based on Byzantine Consistent Broadcast
as its core primitive, foregoing the expenses of full atomic commit channels
(consensus). The resulting system has low-latency for both confirmation and
payment finality. Remarkably, each authority can be sharded across many
machines to allow unbounded horizontal scalability. Our experiments demonstrate
intra-continental confirmation latency of less than 100ms, making FastPay
applicable to point of sale payments. In laboratory environments, we achieve
over 80,000 transactions per second with 20 authorities---surpassing the
requirements of current retail card payment networks, while significantly
increasing their robustness
Narwhal and Tusk: A DAG-based Mempool and Efficient BFT Consensus
We propose separating the task of reliable transaction dissemination from
transaction ordering, to enable high-performance Byzantine fault-tolerant
quorum-based consensus. We design and evaluate a mempool protocol, Narwhal,
specializing in high-throughput reliable dissemination and storage of causal
histories of transactions. Narwhal tolerates an asynchronous network and
maintains high performance despite failures. Narwhal is designed to easily
scale-out using multiple workers at each validator, and we demonstrate that
there is no foreseeable limit to the throughput we can achieve. Composing
Narwhal with a partially synchronous consensus protocol (Narwhal-HotStuff)
yields significantly better throughput even in the presence of faults or
intermittent loss of liveness due to asynchrony. However, loss of liveness can
result in higher latency. To achieve overall good performance when faults occur
we design Tusk, a zero-message overhead asynchronous consensus protocol, to
work with Narwhal. We demonstrate its high performance under a variety of
configurations and faults. As a summary of results, on a WAN, Narwhal-Hotstuff
achieves over 130,000 tx/sec at less than 2-sec latency compared with 1,800
tx/sec at 1-sec latency for Hotstuff. Additional workers increase throughput
linearly to 600,000 tx/sec without any latency increase. Tusk achieves 160,000
tx/sec with about 3 seconds latency. Under faults, both protocols maintain high
throughput, but Narwhal-HotStuff suffers from increased latency