Cloud-assisted verifiable and traceable multi-party threshold private set intersection protocol for ride-sharing scheme

In recent years, ride-sharing services have experienced widespread adoption due to their ability to significantly reduce travel costs and carbon emissions. However, as the demand for ride-sharing increases, users are faced with growing challenges related to privacy protection and data security during the process of sharing transportation resources. In particular, there is a pressing need for effective solutions to mitigate the risks of the leakage of personally sensitive information and insufficient security verification. To address these challenges, a cloud-assisted, traceable ride-sharing scheme is proposed, leveraging a multi-party threshold private set intersection (MP-TPSI) protocol integrated with a digital signature verification mechanism. The proposed framework comprises an innovative MP-TPSI protocol, which includes two primary components: a multi-party cardinality testing phase that employs a secure comparison protocol (SCP) to determine if the intersection size surpasses a predefined threshold, coupled with a Proof of Ownership protocol to trace malicious users; and a PSI phase that securely computes the intersection using cloud-assisted computation. Furthermore, digital signature technology is incorporated to establish a robust verification framework, which ensures the authenticity of user identities and effectively mitigates the risks associated with ride mismatches and privacy leakage. Finally, comparative evaluation results demonstrate that the proposed MP-TPSI protocol achieves effective privacy protection with lower communication and computational overhead compared to existing schemes.