Permissioned Blockchain-Based Secure and Privacy-Preserving Data Sharing Protocol

In this Internet of Things era, privacy preserving is one of the most vital barriers for personal data sharing. In this article, we present a secure and privacy-preserving data sharing protocol over the permissioned blockchains which require to certificate the users before they submit the transactions. We use the structure-preserving Groth signature to construct the anonymous credentials for satisfying the requirement of permissioned blockchains, and the anonymous credentials does not disclose the real identities of data owners. We prove that the anonymous credential in our protocol achieves the ideal functionality. For the secure access control and privacy protection of the data accessors, we propose an efficiently anonymous authentication scheme which utilizes the ElGamal commitment and the one-out-of-many proof to ensure a data accessor is authorized, but any unauthorized entities cannot learn the real identity of the data accessor, and even the data owner does not know who (although in the access control list) and when downloads his/her data. The blockchain platform is used to record the data storing, access control list, and the storage addresses, which helps to enhance the security level of the protocol. We implement our protocol over the ThinkPad, the RaspBerry Pi, the Huawei cloud, and the Hyperledger Fabric, and the experiments show the good performances.