# Online Payments by Merely Broadcasting Messages (Extended Version)

arXiv: https://arxiv.org/abs/2004.13184 · HTML: https://mlsanity.com/paper/2004.13184/

## Key facts

- Cited by 1 papers in the map (data through 14 Oct 2026).
- First posted on arXiv 27 Apr 2020.

## Built on by (most cited first, 1 of 1)

- [Foundations for Grassroots Democratic Metaverse](https://mlsanity.com/paper/2203.04090/) (2022)

## Abstract (arXiv)

We address the problem of online payments, where users can transfer funds among themselves. We introduce Astro, a system solving this problem efficiently in a decentralized, deterministic, and completely asynchronous manner. Astro builds on the insight that consensus is unnecessary to prevent double-spending. Instead of consensus, Astro relies on a weaker primitive---Byzantine reliable broadcast---enabling a simpler and more efficient implementation than consensus-based payment systems. In terms of efficiency, Astro executes a payment by merely broadcasting a message. The distinguishing feature of Astro is that it can maintain performance robustly, i.e., remain unaffected by a fraction of replicas being compromised or slowed down by an adversary. Our experiments on a public cloud network show that Astro can achieve near-linear scalability in a sharded setup, going from 10K payments/sec (2 shards) to 20K payments/sec (4 shards). In a nutshell, Astro can match VISA-level average payment throughput, and achieves a 5× improvement over a state-of-the-art consensus-based solution, while exhibiting sub-second 95th percentile latency.