Secure Off-chain Payment in Consortium Blockchain System

Abstract

Off-chain payment channel is a significant technology to improve transaction performance of blockchain by enabling two blockchain nodes to conduct micro-payments at high frequency without committing all of the transactions on the blockchain, ensuring the “instant finality” of transactions, reducing transaction costs and improving the scalability of the blockchain. Among different types of blockchains, the transaction performance of consortium blockchain is better than that of public blockchain, thus the application of state channel technology in consortium blockchain will further improve the transaction throughput. However, as far as we know, there seems to be seldom existing work in this aspect. A critical challenge is that the existing work applies the state channel technology only in the public blockchain system, and there are many differences between the consortium and public blockchain system in terms of architecture, application scenarios and privacy, etc., leading to certain technical thresholds for migration of the state channel technology. In this paper, we address this challenge by designing CBOP, an off-chain payment service that can interact with the consortium blockchain infrastructure of the Hyperledger Fabric. CBOP can carry out on-chain or off-chain transactions according to the demand of both parties, and provide strong security to protect against malicious attacks. It implements these benefits through two novel designs, dynamic partitioning algorithm for transactions and trusted security guarantee for off-chain payments. Experimental results show that CBOP can provide 300 % more transaction throughput than original design.