Privacy-Preserving Blockchain-Based Traceability System with Decentralized Ciphertext-Policy Attribute-Based Encryption

Traceability, being the ability to access information of an item throughout its lifecycle, plays an important part in current supply chain, facilitating prompt response in case of incidents. In recent years, blockchain-based traceability systems are proposed to address the multi-party data exchange issue with the emerging technology while achieving external traceability. To tackle the privacy issues that arose in blockchain-based traceability system, we propose and implement an architecture of privacy-preserving blockchain-based traceability system. We propose a statically-secure decentralized ciphertext-policy attribute-based encryption (DCP-ABE) scheme with delegation and hidden access policy, which is integrated together with zero-knowledge succinct non-interactive arguments of knowledge (zk-SNARK) into the proposed system. The proposed system is implemented with Quorum, InterPlanetary File System (IPFS), Dgraph and hierarchical deterministic key generation. These components and cryptographic algorithms help the implemented system achieve data confidentiality and improve the identity anonymity, which are important to safeguard trade secrets. A case study of product recall, in collaboration with a company in Hong Kong, is also conducted to demonstrate how the implemented system can assist.