PPChain: A Privacy-Preserving Permissioned Blockchain Architecture for Cryptocurrency and Other Regulated Applications

Abstract

Existing (popular) blockchain architectures, including the widely used Ethereum and Hyperledger, are generally not designed to achieve conflicting properties such as anonymity and regulation, and transparency and confidentiality. In this article, we propose a privacy-preserving permissioned blockchain architecture (PPChain) that permits one to also introduce regulation, where PPChain's architecture is modified from that of Ethereum. Specifically, we integrate the cryptographic primitives (group signature and broadcast encryption), and adopt practical byzantine fault tolerance consensus protocol with a validate-record separation mechanism, as well as removing the transaction fee and mining reward. To show the utility of PPChain, we provide qualitative security and privacy analysis, and performance analysis. We also explain how PPChain can be deployed in regulation applications, using cryptocurrency, food supply chain, and sealed-bid auctions as examples.