IoT data exchange services are emerging to connect various and distributed IoT data sources, which facilitate data owners exchange their IoT data flexibly. Traditional IoT data exchange services rely on a centralized third-party to negotiate the settlement of trades between data consumers and providers. Such settlement model suffers from issues including single point of failure, extra settlement fee, un-transparency of settlement details, to name a few. New settlement model is imperative to overcome such limitations. Blockchain is an innovative technology that is competent in governing the decentralized network, which poses great opportunity to implement fair settlement in decentralized manner. In this paper, we propose a Blockchain-enabled settlement model for decentralized IoT data exchange services. Firstly, Bitcoin-based time commitment scheme is adopted to build fair and autonomous settlement model. Furthermore, to enhance the accountability of all transactions, an optimized practical Byzantine fault tolerant consensus protocol named ReBFT, is proposed to enable all members involved in the IoT data exchange application achieve identical shared ledger recording all transactions. Finally, experiments are conducted to verify the feasibility of our proposal.

物联网数据交换服务正在兴起，以连接各种分布式物联网数据源，从而方便数据所有者灵活地交换其物联网数据。传统的物联网数据交换服务依赖于一个集中的第三方来协商数据消费者和提供商之间的交易结算。这样的结算模型存在包括单点故障，额外的结算费用，结算细节不透明等问题。必须采用新的结算模型来克服这些限制。区块链是一项创新技术，能够胜任管理去中心化网络，这为以去中心化方式实施公平结算提供了巨大的机会。在本文中，我们为分散式物联网数据交换服务提出了启用区块链的结算模型。首先，采用基于比特币的时间承诺方案，建立公平，自主的结算模型。此外，为了增强所有交易的责任性，提出了一种优化的实用的拜占庭容错共识协议ReBFT，以使IoT数据交换应用程序中涉及的所有成员实现记录所有交易的相同共享账本。最后，进行实验以验证我们建议的可行性。