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Blockchain-Based Fine-Grained Data Sharing for Multiple Groups in Internet of Things

Cloud-based Internet of Things, which is considered as a promising paradigm these days, can provide various applications for our society. However, as massive sensitive and private data in IoT devices are collected and outsourced to cloud for data storage, processing, or sharing for cost saving, the data security has become a bottleneck for its further development. Moreover, in many large-scale IoT systems, multiple group data sharing is practical for users. Thus, how to ensure data security in multiple group data sharing remains an open problem, especially the fine-grained access control and data integrity verification with public auditing. Therefore, in this paper, we propose a blockchain-based fine-grained data sharing scheme for multiple groups in cloud-based IoT systems. In particular, we design a novel multiauthority large universe CP-ABE scheme to guarantee the fine-grained access control and data integrity across multiple groups by integrating group signature into our scheme. Moreover, to ease the need for a trusted third auditor in traditional data public auditing schemes, we introduce blockchain technique to enable a distributed data public auditing. In addition, with the group signature, our scheme also realizes anonymity and traitor tracing. The security analysis and performance evaluation show that our scheme is practical for large-scale IoT systems.