A hierarchical access control and sharing model for healthcare data with on-chain-off-chain collaboration

Abstract

Healthcare data is growing rapidly and data sharing is becoming increasingly important among hospitals. However, traditional methods are prone to data leakage and threaten patient privacy. To ensure data security and realize sharing and access control, combining blockchain technology, attribute-based encryption and ciphertext policy (CP-ABE) and AES symmetric encryption algorithm, this paper proposes a hierarchical attribute-based encryption algorithm based on master-sidechain (MSC-CP-ABE) and a collaborative access control and sharing model with on-chain and off-chain (AC-CSS). The algorithm encrypts hierarchically based on data sensitivity, the ciphertext is stored in the interplanetary file system (IPFS), and the encrypted address and key are stored in the side chain, which is convenient for indexing in the main chain. The vectorized access policy implements policy hiding, combines on-chain and off-chain, saves blockchain space, achieves hierarchical access control, and improves security and efficiency. Simulation experiments show that the main sidechain model proposed in this paper has better performance in terms of transaction delay and throughput. Compared with existing models, the algorithm proposed in this paper has certain advantages in data encryption and decryption time and key generation time.