PrivChain: Provenance and Privacy Preservation in Blockchain enabled Supply Chains

TL;DR

PrivChain is a blockchain framework that uses zero knowledge proofs to ensure provenance and traceability of supply chain data while preserving trade secrets and minimizing overhead.

Contribution

It introduces PrivChain, a novel privacy-preservation framework employing zero knowledge range proofs and an incentive mechanism for secure, efficient supply chain data management.

Findings

Minimal overhead observed in Hyperledger Fabric implementation

Effective protection of trade secrets with provable provenance

Automated verification and incentive processes using smart contracts

Abstract

Blockchain offers traceability and transparency to supply chain event data and hence can help overcome many challenges in supply chain management such as: data integrity, provenance and traceability. However, data privacy concerns such as the protection of trade secrets have hindered adoption of blockchain technology. Although consortium blockchains only allow authorised supply chain entities to read/write to the ledger, privacy preservation of trade secrets cannot be ascertained. In this work, we propose a privacy-preservation framework, PrivChain, to protect sensitive data on blockchain using zero knowledge proofs. PrivChain provides provenance and traceability without revealing any sensitive information to end-consumers or supply chain entities. Its novelty stems from: a) its ability to allow data owners to protect trade related information and instead provide proofs on the data, and b) an integrated incentive mechanism for entities providing valid proofs over provenance data. In particular, PrivChain uses Zero Knowledge Range Proofs (ZKRPs), an efficient variant of ZKPs, to provide origin information without disclosing the exact location of a supply chain product. Furthermore, the framework allows to compute proofs and commitments off-line, decoupling the computational overhead from blockchain. The proof verification process and incentive payment initiation are automated using blockchain transactions, smart contracts, and events. A proof of concept implementation on Hyperledger Fabric reveals a minimal overhead of using PrivChain for blockchain enabled supply chains.