Blizzard: a Distributed Consensus Protocol for Mobile Devices

TL;DR

Blizzard is a Byzantine Fault Tolerant distributed ledger protocol designed for mobile devices, utilizing a two-tier architecture with online brokers to ensure safety, liveness, and high performance in terms of throughput and latency.

Contribution

It introduces a novel two-tier architecture with decentralized broker matching and provides mathematical safety guarantees for mobile device-based consensus.

Findings

Capable of several thousand transactions per second per shard

Achieves sub-second confirmation latency

Provides mathematical safety bounds for malicious node ratios

Abstract

We present Blizzard, a Byzantine Fault Tolerant (BFT) distributed ledger protocol that is aimed at making mobile devices first-class citizens in the consensus process. Blizzard introduces a novel two-tier architecture by having the mobile nodes communicate through online brokers, and includes a decentralized matching scheme to ensure each node connects to a certain number of random brokers. Through mathematical analysis, we derive a guaranteed safety region (i.e. the set of ratios of malicious nodes and malicious brokers for which the safety is assured) for the Blizzard protocol. Liveness is shown as well. We analyze the performance of Blizzard in terms of its throughput, latency and message complexity. Through experiments based on a software implementation, we show that Blizzard is capable of throughput on the order of several thousand transactions per second per shard, and sub-second confirmation latency.