Iranian Society of Cryptology The ISC International Journal of Information Security 2008-2045 17 1 2025 01 01 Enhancing Lattice-Based Attribute-Based Encryption with Robust Fine-Grained Access Policies 13 23 201899 10.22042/isecure.2024.436486.1082 EN Sedigheh Khajouei-Nejad Department of Engineering, North Tehran Branch, Islamic Azad University, Tehran, Iran Sam Jabbehdari Department of Engineering, North Tehran Branch, Islamic Azad University, Tehran, Iran Hamid Haj Seyyed Javadi Department of Computer Engineering, Shahed University, Tehran, Iran Seyed Mohammad Hossein Moattar Department of Computer engineering, Mashhad branch, Islamic Azad University, Mashhad, Iran Journal Article 2024 01 18 Protecting sensitive data is crucial in various fields, including Information Technologies, Network Security, and healthcare records. Implementing precise access policies for encrypted data is vital in large networks. Attribute-Based Encryption (ABE) emerges as a solution to this challenge, enabling encryption and access control simultaneously. With the increasing significance of quantum-safe measures due to advancements in quantum computing, there is a growing need for quantum-resistant access control mechanisms for encrypted data, as addressed by Lattice-Based Attribute-Based Encryption.<br />However, some existing Lattice-Based ABE schemes lack robust support for fine-grained access policies. In this paper, we present an enhancement to a Key Policy Attribute-Based Encryption (ABE) scheme to not only accommodate threshold gates but also any boolean circuits. Our proposed scheme's security is grounded in the Learning with Errors (LWE) assumption within the selective security model under the Indistinguishable CPA game. Importantly, the scheme is well-suited for the Disjunctive Normal Form (DNF) representation of boolean functions, offering enhanced flexibility and security in access control mechanisms for encrypted data. https://www.isecure-journal.com/article_201899_87ccc790bc0c23cc28cea7742631768c.pdf