Privacy-Preserving Multi-Party Transaction Auditing for Social Financial Technology

Social financial technology is an emerging technology that integrates social networks with financial technology, leveraging distributed and intelligent technologies such as blockchain, big data, and artificial intelligence to provide users with diverse and flexible services. However, the flexibility and diversity of transaction services imply that transactions occur among multiple parties, who are often mutually untrusting. As such, arbitration and verification of transactions are essential to ensure the proper functioning of social financial technology. Relying on government or other authoritative entities to endorse and provide real-time verification services for transactions poses significant challenges. Beyond the immense storage and computational overhead of auditing a large volume of transactions, government entities cannot provide round-the-clock auditing services. To address these challenges, we propose the Privacy-Preserving Multi-Party Transaction Auditing Scheme for Social Financial Technology (PMTA). PMTA first designs a two-round negotiation process to establish consistent transaction information and secret values among untrusting transaction parties. Subsequently, the authority generates transaction backups and auditing metadata, with the transaction backups stored by multiple service providers and the auditing metadata stored on the blockchain. The authority can then delete the generated information. The transaction backups created by the authority do not expose the details of the transactions, thereby protecting user privacy. Finally, based on the provable data possession (PDP) framework, PMTA constructs a periodic auditing process for transaction information. We analyze the security of PMTA and evaluate its performance through experiments. The results demonstrate that PMTA not only achieves secure auditing of transaction information and protects user privacy but also outperforms comparison schemes in terms of computational overhead.