Scalable Multi-Chain Coordination via the Hierarchical Longest Chain Rule

TL;DR

This paper presents BlockReduce, a hierarchical PoW blockchain system that enables high throughput and seamless cross-chain state transitions by merging multiple parallel blockchains, scaling superlinearly with the number of chains.

Contribution

It introduces a novel hierarchical multi-chain protocol that leverages merged mining and cross-chain state transitions to significantly improve scalability.

Findings

Achieves superlinear scaling of transaction throughput with the number of blockchains.

Enables seamless cross-blockchain state transitions within the core protocol.

Utilizes full PoW security across all merged chains.

Abstract

This paper introduces BlockReduce, a Proof-of-Work (PoW) based blockchain system which achieves high transaction throughput through a hierarchy of merged mined blockchains, each operating in parallel on a partition the overall application state. Most notably, the full PoW available within the network is applied to all blockchains in BlockReduce, and cross-blockchain state transitions are enabled seamlessly within the core protocol. This paper shows that, given a hierarchy of blockchains and its associated security model, the protocol scales superlinearly in transaction throughput with the number of blockchains operated by the protocol.