CrowdChain: A privacy-preserving crowdfunding system based on blockchain and PUF

Crowdfunding refers to the online collection of certain capital from a vast number of individuals or groups that each contribute a relatively small amount. Recently, the credibility of crowdfunding platforms has been undermined by fraudulent projects, inadequate fund management, and other forms of disorder. The decentralization and anti-tampering features of blockchain provide the possibility to solve the above problems, and many studies have proposed blockchain-based crowdfunding schemes. However, the existing state-of-the-art methods do not provide user authentication, transaction auditing, and identity management in a privacy-preserving way. Accordingly, this paper presents a novel blockchain-based crowdfunding system called CrowdChain. Initially, the distributed identity and BLS signature are employed to establish a user authentication mechanism, enabling CrowdChain to withstand Sybil attacks while preserving the non-linkability of user identities. Secondly, the physically unclonable function (PUF) is used to generate keys associated with digital identities that are not stored in external devices to resist physical attacks. Subsequently, a crowdfunding mechanism is constructed utilizing zero-knowledge proofs to facilitate streamlined auditing procedures while safeguarding the confidentiality of transactions. Additionally, the formal security analysis proves the security of the CrowdChain scheme. The system prototype is implemented on the Hyperledger Fabric. Empirical evidence indicates the viable efficiency of CrowdChain.