Paper 2025/345

Publicly Verifiable Threshold Proxy Re-encryption and Its Application in Data Rights Confirmation

Abstract

Proxy re-encryption (PRE) has been regarded as an effective cryptographic primitive in data sharing systems with distributed proxies. However, no literature considers the honesty of data owners, which is critical in the age of big data. In this paper, we fill the gap by introducing a new proxy re-encryption scheme, called publicly verifiable threshold PRE (PVTPRE). Briefly speaking, we innovatively apply a slightly modified publicly verifiable secret sharing (PVSS) scheme to distribute the re-encryption keys to multiple proxies. Consequently, we achieve publicly verifiability of data owners non-interactively. Then, the correctness of data users in decryption and public verifiability of proxies in re-encryption are guaranteed seamlessly through execution of the PVSS reconstruction algorithms. We further prove that PVTPRE satisfies IND-CPA security. Besides, we put forward a privacy-preserving data rights confirmation framework by providing clear principles for data ownership and usage, based on the PVTPRE scheme and blockchain. Blockchain plays the role of data bank and smart contract engine, providing reliable storage and verification for all framework. To our knowledge, we are the first to systematically investigate data rights confirmation considering privacy as well as public verifiability, addressing the growing need for robust mechanisms to protect data rights and ensure transparency. Finally, we conduct comprehensive experiments to illustrate the correctness, feasibility and effectiveness. The experimental results show that our PVTPRE outperforms other PREs in many aspects.