A blockchain-based secure data sharing scheme with efficient attribute revocation

With the growth of interdisciplinary projects, cooperation among organizations and secure file sharing are increasingly crucial. The lead party manages these files and must ensure project participants can access them while preventing unauthorized access. CP-ABE(Ciphertext-Policy Attribute-Based Encryption) demonstrates advantages in achieving fine-grained access control through its unique encryption and decryption strategy. However, flawed permission management, lack of traceability and complex ciphertext updatings present challenges. To address these issues, we propose an enhanced CP-ABE scheme for secure data sharing and participant management, along with a tree-based searchable encryption for file index protection. The chameleon hash function assigns unique identities to participants, preventing unauthorized access. Smart contracts and blockchain ensure traceability, and a re-encryption scheme efficiently updates ciphertext without modifying ciphertext of project files. Our solution enhances data sharing efficiency, protects file confidentiality, and enables malicious activity traceability.