I. Introduction
As the production mode combining traditional industry and Internet technology, the Industrial Internet can fully interconnect people and machines through cloud storage, cloud computing, cloud Internet of Things (IoT), and other cloud service technologies, creating an open, efficient, scalable, expandable, intelligent, and highly integrated industrial environment. The Industrial Internet is the solution to industrial digitalization and networking in the 21st century [1]. Fig. 1 shows the architecture of the Industrial Internet [2]. The architecture consists of the industry layer, enterprise layer, edge layer, and device layer, embedded with the edge system, enterprise platform, and industry platform. The rapid development of the Industrial Internet has accelerated the growth and shaping of the industrial data element market. In the Industrial Internet, industrial data are mainly shared within or between enterprises: 1) data sharing within the enterprise, including between equipment and equipment, between equipment and people, and between people and people. For example, engineers at the equipment layer through the industrial equipment interface of the edge system (data flow ① in Fig. 1) store the field data in the private cloud servers (data flow ② in Fig. 1). The manager at the enterprise layer reads data (data flow ③ in Fig. 1) and 2) enterprise-to-enterprise data sharing, e.g., data sharing between enterprises (data flow ④ in Fig. 1), and enterprises storing the industrial data assets in the public cloud server (data flow ⑤ in Fig. 1). However, to use cloud service technologies, such as cloud storage, cloud computing, and cloud IoT, the industrial control system needs to be connected to the Internet. The originally closed data environment is transformed into the open environment [3]. In the general industrial control system, data are transferred in plaintext, so that data are vulnerable to theft and tampering in the open network environment. As in Fig. 1, an attacker intrudes from the public cloud server and steals plaintext data from public and private cloud servers. Encrypting industrial shared data is a simple means, but how to achieve precise and flexible access control for encrypted industrial data remains a challenge.
Industrial Internet architecture.