SI-CP-ABE: an isogeny-based ciphertext-policy attribute-based encryption scheme
Xiwen Chen, Jinrong Chen, Xu Zheng, Zhou Zijian
Abstract
Ciphertext-policy attribute-based encryption (CP-ABE) serves as a fundamental cryptographic primitive for fine-grained data access control. However, existing schemes, primarily based on bilinear maps or lattice hardness assumptions, generally suffer from large system parameters, key sizes, and ciphertext sizes, which severely restrict their deployment in resource-constrained scenarios. To address this challenge, a novel CP-ABE scheme based on supersingular elliptic curve isogeny (SI-CP-ABE) is proposed. This scheme integrates the action of isogeny ideal class group with linear secret sharing schemes, achieving efficient fine-grained access control in a post-quantum security setting. Regarding security, two new hardness assumptions—P+-CSSCDH and P+-CSSDDH—are proposed, based on which the scheme is rigorously proven to satisfy indistinguishability under chosen plaintext attack in the selective security model. To further enhance performance, an optimized scheme is designed based on SI-CP-ABE. Furthermore, based on the core algebraic structure of SI-CP-ABE, a post-quantum Naor-Reingold-type pseudo-random function with authentication capability is constructed, thereby enriching the building blocks for post-quantum cryptographic protocols.