Efficient Traceable Attribute-Based Encryption Scheme with Dynamic Access Control Based on Blockchain

The features of decentralization and tamper-proof enable blockchain to be an emerging technology for integrity protection of important data  stored on it. Blockchains are also used to combine with cloud storage for access control and sharing of private data. To protect the confidentiality of the private data, attribute-based encryption (ABE) schemes that can provide one-to-many encryption are commonly used as the solutions. However, there are problems, such as inefficiency, key abuse, and inflexibility of access control policy, when adopting ABE solutions. This paper proposes an efficient traceable attribute-based encryption with dynamic access control (TABE-DAC) scheme based on blockchain for fine-grained sharing of encrypted private data on cloud. The proposed TABE-DAC scheme supports traceability for the accountability of malicious users who leak the private key. The proposed solution also realizes dynamic access control where data owners have the flexibility to update access control policy. We also prove the security of the proposed TABE-DAC scheme. Finally, through theoretical comparison and experimental analysis, we verify the efficiency of the proposed solution.

INDEX TERMS: Access control, key abuse, private data, cloud storage, attribute-based encryption, confidentiality, blockchain.