zkrpChain: Towards multi-party privacy-preserving data auditing for consortium blockchains based on zero-knowledge range proofs

Consortium blockchain has been widely used in different scenarios, where blockchain members demand that their uploaded data could be audited based on data range under their identities without exposing the data themselves. However, so far, current solutions only support simple (e.g., standard-range) privacy-preserving data auditing, and can not be used in multi-party scenarios. To address the problem, we propose zkrpChain, which focuses on protection of the integrity and privacy of the data uploaded by blockchain members while leaving their identities public. In zkrpChain, which is based on Hyperledger Fabric and Bulletproofs, both standard-range and arbitrary-range zero-knowledge range proofs generation and verification are supported. To improve the efficiency, the aggregation of multiple proofs and batch verification are developed. Furthermore, to broaden the application scenarios, we also develop multi-party proofs generation and verification. To support further development, we provide chaincodes, related APIs together with the client codes. Finally, we conduct experiments to evaluate the performance of zkrpChain, and the results show that as the total data size grows exponentially, the proof and verification time only grow linearly while the total on-chain storage grows logarithmically.