SoK: Privacy-preserving smart contract

Abstract

The privacy concern in smart contract applications continues to grow, leading to the proposal of various schemes aimed at developing comprehensive and universally applicable privacy-preserving smart contract (PPSC) schemes. However, the existing research in this area is fragmented and lacks a comprehensive system overview. This paper aims to bridge the existing research gap on PPSC schemes by systematizing previous studies in this field. The primary focus is on two categories: PPSC schemes based on cryptographic tools like zero-knowledge proofs, as well as schemes based on trusted execution environments. In doing so, we aim to provide a condensed summary of the different approaches taken in constructing PPSC schemes. Additionally, we also offer a comparative analysis of these approaches, highlighting the similarities and differences between them. Furthermore, we shed light on the challenges that developers face when designing and implementing PPSC schemes. Finally, we delve into potential future directions for improving and advancing these schemes, discussing possible avenues for further research and development.

Keywords

Privacy / Smart contract / Zero-knowledge proof / Trusted execution environment / Blockchain

Declaration of competing interest

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

Acknowledgments

This study was partially supported by the National Key R&D Program of China (2022YFB4501000), the National Natural Science Foundation of China (62232010 and 62302266), Shandong Science Fund for Excellent Young Scholars, China (2023HWYQ-008), Shandong Science Fund for Key Fundamental Research Project, China (ZR2022ZD02), and the Fundamental Research Funds for the Central Universities, China.

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