VB-CP-ABE: An Improved CP-ABE Scheme Based on Blockchain Collaboration and Fine-Grained Version Control

Abstract

To address the shortcomings of data privacy protection in fruit traceability systems and the high revocation overhead of traditional CP-ABE schemes when personnel changes are frequent, this paper proposes an improved traceability system based on blockchain collaboration and version control. First, a two-layer "on-chain-off-chain" storage architecture is designed: IPFS is used to store AES-encrypted traceability data, while a consortium blockchain stores access policies, ciphertext indexes, and a global attribute version table, effectively alleviating on-chain storage pressure while ensuring data immutability. Second, a VB-CP-ABE algorithm based on version control is constructed. This algorithm cryptographically binds user attribute private keys to dynamic version numbers stored on the blockchain. When permission needs to be revoked, the version number of a specific attribute on the chain is updated via a smart contract, ensuring that the newly generated or published ciphertext cannot cancel the hash entries when decrypting with the old version private key, thus achieving immediate forward revocation. For users who still need to retain permissions, only incremental issuance of new version private key components for the affected attributes is required. Simulation results show that the proposed scheme outperforms comparative schemes in key generation, encryption, and decryption efficiency while ensuring access control security, demonstrating significant practical application value.