Authors: Cong Peng, Rongmao Chen, Yi Wang, Debiao He, Xinyi Huang

 

Title: Parameter-Hiding Order-Revealing Encryption without Pairings

 

Conference: The 27th International Conference on Practice and Theory of Public-Key Cryptography (PKC)

 

Abstract: Order-Revealing Encryption (ORE) provides a practical solution for conducting range queries over encrypted data. Achieving a desirable privacy-efficiency tradeoff in designing ORE schemes has posed a significant challenge. At Asiacrypt 2018, Cash et al. proposed Parameterhiding ORE (pORE), which specifically targets scenarios where the data distribution shape is known, but the underlying parameters (such as mean and variance) need to be protected. However, existing pORE constructions rely on impractical bilinear maps, limiting their real-world applicability. In this work, we propose an alternative and efficient method for constructing pORE using identification schemes. By leveraging the map-invariance property of identification schemes, we eliminate the need for pairing computations during ciphertext comparison. Specifically, we instantiate our framework with the pairing-free Schnorr identification scheme and demonstrate that our proposed pORE scheme reduces ciphertext size by approximately 31.25% and improves encryption and comparison efficiency by over two times compared to the current stateof-the-art pORE construction. Our work provides a more efficient alternative to existing pORE constructions and could be viewed as a step towards making pORE a viable choice for practical applications.