Improved Secure Efficient Delegated Private Set Intersection
This work addresses security and efficiency issues in cloud-based private set intersection for parties needing to compute common data without disclosing private information, representing an incremental improvement over prior schemes.
The paper tackles the vulnerability of the EO-PSI delegated private set intersection scheme to eavesdropping attacks without secure channels, proposing an improved protocol that eliminates the need for secure channels while reducing computational complexity and enhancing fairness.
Private Set Intersection (PSI) is a vital cryptographic technique used for securely computing common data of different sets. In PSI protocols, often two parties hope to find their common set elements without needing to disclose their uncommon ones. In recent years, the cloud has been playing an influential role in PSI protocols which often need huge computational tasks. In 2017, Abadi et al. introduced a scheme named EO-PSI which uses a cloud to pass on the main computations to it and does not include any public-key operations. In EO-PSI, parties need to set up secure channels beforehand; otherwise, an attacker can easily eavesdrop on communications between honest parties and find private information. This paper presents an improved EO-PSI scheme which has the edge on the previous scheme in terms of privacy and complexity. By providing possible attacks on the prior scheme, we show the necessity of using secure channels between parties. Also, our proposed protocol is secure against passive attacks without having to have any secure channels. We measure the protocol's overhead and show that computational complexity is considerably reduced and also is fairer compared to the previous scheme.