sedigheh khajouei-nejad

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.

Applying access control to encrypted data is a crucial aspect of network security. Although Attribute-Based Encryption (ABE) provides a suitable solution, it comes with limitations, primarily its high computational complexity due to the use of pairing operations. In this paper, we propose the first attribute-based encryption scheme based on RSA encryption, which is pairing-free and more efficient than previous pairing-based approaches. This scheme is particularly well-suited for lightweight applications such as those in the Internet of Things (IoT).
The proposed encryption scheme is a Key-Policy Attribute-Based Encryption (KP-ABE) that allows its access policy to be any Boolean function in disjunctive normal form (DNF). Our scheme also addresses the challenge of key revocation, which is often problematic in ABE schemes. The key advantages of our scheme are its efficiency and simplicity compared to other ABE schemes, which typically rely on complex pairing operations. Additionally, we present an Attribute-Based Signature (ABS) scheme based on RSA.

In recent years, the problem of online data and information security has been increasingly serious and prevalent. Security issues are resolved via cryptography. Access control over the encrypted messages is necessary for some applications, therefore message encryption cannot simply achieve the stated aims. To achieve these requirements, attribute-based encryption (ABE) is used. This type of encryption provides both security and access structure for the network users simultaneously. Fuzzy Identity-Based Encryption (FIBE) is a special mode of ABE that provides a threshold access structure for the users. This threshold value is set by the authority for users, which is always fixed and cannot be changed. So, the sender (encryptor) will not play a role in determining the threshold value. The mentioned issue exists also in Key Policy Attribute Based Encryption (KP-ABE) schemes. In this paper, we present a FIBE scheme in addition to the authority, the sender also plays a role in determining the threshold value. Thus, the policy will be more flexible than previous FIBE schemes in that the threshold value is selected only by the authority. We can call the proposed scheme a dual-policy ABE. The proposed technique for flexibility of threshold value can be applied in most of exist KP-ABE schemes. We use the (indistinguishable) selective security model for a security proof. The hardness assumption that we use is the modified bilinear decision Diffie-Hellman problem.

—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.