Reinshard: An optimally sharded dual-blockchain for concurrency resolution

TL;DR

Reinshard introduces a dual-blockchain architecture utilizing hybrid PoW/PoS consensus and Verifiable Delay Functions to enable secure, efficient, and concurrent cross-shard operations, improving blockchain scalability and performance.

Contribution

The paper proposes Reinshard, a novel dual-blockchain system that resolves cross-shard concurrency issues using hybrid consensus and VDF, advancing sharding techniques for scalable blockchains.

Findings

Reinshard effectively resolves cross-shard concurrency conflicts.

Experimental results demonstrate improved scalability and security.

The architecture supports parallel operations with reduced node burden.

Abstract

Decentralized control, low-complexity, flexible and efficient communications are the requirements of an architecture that aims to scale blockchains beyond the current state. Such properties are attainable by reducing ledger size and providing parallel operations in the blockchain. Sharding is one of the approaches that lower the burden of the nodes and enhance performance. However, the current solutions lack the features for resolving concurrency during cross-shard communications. With multiple participants belonging to different shards, handling concurrent operations is essential for optimal sharding. This issue becomes prominent due to the lack of architectural support and requires additional consensus for cross-shard communications. Inspired by hybrid Proof-of-Work/Proof-of-Stake (PoW/PoS), like Ethereum, hybrid consensus and 2-hop blockchain, we propose Reinshard, a new blockchain that inherits the properties of hybrid consensus for optimal sharding. Reinshard uses PoW and PoS chain-pairs with PoS sub-chains for all the valid chain-pairs where the hybrid consensus is attained through Verifiable Delay Function (VDF). Our architecture provides a secure method of arranging nodes in shards and resolves concurrency conflicts using the delay factor of VDF. The applicability of Reinshard is demonstrated through security and experimental evaluations. A practical concurrency problem is considered to show the efficacy of Reinshard in providing optimal sharding.