learning with errors(lwe)

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.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.

—In order to provide access control on encrypted data, Attribute-based encryption (ABE) defines each user using a set of attributes. Fuzzy identity-based encryption (FIBE) is a variant of ABE that allows for a threshold access structure for users. To address the potential threat posed by future quantum computers, this paper presents a postquantum fuzzy IBE scheme based on lattices. However, current lattice-based ABE schemes face challenges related to computational complexity and the length of ciphertext and keys. This paper aims to improve the performance of an existing fuzzy IBE scheme by reducing key length and computational complexity during the encryption phase. While negative attributes are not utilized in our scheme, we prove its security under the learning with error (LWE) hard problem assumption in the selective security model. These improvements have significant implications for the field of ABE.