## 1 Introduction  
In recent years, the Internet of Things (IoT) has been widely used in industry, especially manufacturing, realizing intelligent industrial Internet of Things (IIoT) applications. It is estimated that by 2025, there will be 4.16 billion IoT devices worldwide, which are expected to generate 79.4 ZB of data [1]. How to manage and use IoT data to realize intelligence in an efficient, safe, and economical way has become an important research issue.  
As a cutting-edge technology, the emergence of the IIoT enables more industrial entities to achieve interconnection. This has attracted widespread attention from many industries, such as industrial manufacturing, retail, logistics, environmental governance, energy, and medical care. In different industries, the IIoT can facilitate life and improve production efficiency by connecting different types of entities. The IIoT collects real-time data onto connected entities based on different requirements. The data can be used to describe the performance, attributes, and status of the entities to control and monitor different operations on the entities. In the IIoT, uninterrupted manufacturing production is bound to generate a large amount of data, which is collected by the sensors of thousands of entities connected to the IIoT. The obtained data is a precious resource, the security of which needs to ensured in the process of transmission and sharing. It is therefore increasingly important to ensure data privacy and security in the IIoT [2]. At the same time, trust in the exchange of data that has arisen in accounting for the consumption of water, gas, oil, and metering readings in production systems is an essential part of the relationships in the supply chain.  
Blockchain is regarded as a reasonable solution to the above problems. Blockchain can reduce the need for audits and inspections in data transmission in operational technology (OT) environments. Blockchain was originally designed to be applied to the Bitcoin system to provide secure and reliable transactions [3]. However, blockchain still has great challenges in terms of high throughput and scalability, which hinder its development into a general platform suitable for different application scenarios [4]. If the blockchain-based IIoT is used in different scenarios, there are high requirements for TPS (transactions per second). At present, there are different solutions for solving the blockchain scalability problems--off-chain payment networks, BitCoin-NG, and the sharding mechanism, etc. For off-chain payment networks, the typical solution is the Lightning Network, which solves the scalability problem by reducing on-chain redundancy. Bitcoin Cash handles scalability issues by adjusting the block size and block generation speed; Bitcoin-NG [5] divides the block into KeyBlock for leader election and MicroBlock for recording transactions, shortening the time of mining and block confirmation. The sharding technology only allows some nodes in the network to process a certain transaction, the network is divided into many shards, and each shard can process different transactions at the same time, which improves the scalability. However, there are mutual constraints between the scalability, centralization, security, and latency of the blockchain. Therefore, when using blockchain as a means of data storage in the IIoT, the scalability cannot be improved blindly, and the balance between these four needs to be considered [6].