Lattice-based Attribute-based encryption is a well-known cryptographic mechanism that can resist quantum attacks and has the ability of fine-grained access control, and it has a wide range of application scenarios in current Internet of Thing (IoT) era. However, lack of efficiency and existing the problem of large ciphertext expansion rate are the main disadvantages impede the applications of this mechanism. Thus, we propose an efficient and practical ciphertext policy attribute-based encryption (CP-ABE) scheme from lattices in the paper. In this scheme, to make the secret key reusable, we adjust access tree and propose a basic access tree structure, which can be converted from disjunctive normal form, and combine it with a light post-quantum scheme of Kyber. In addition, the compression method and plaintext expansion method are introduced to optimize the scheme. Our CP-ABE scheme is secure against chosen plaintext attack under the hardness of module learning with errors problem. We implement our scheme and compare it with three recent related schemes in terms of security, function and communication cost. Experiments and comparisons show that our CP-ABE scheme has advantages in high encryption efficiency, small matrix dimension, small key sizes, and low ciphertext expansion rate, which has some merit in practice.
Ciphertext policy attribute-based encryption (CP-ABE) is a promising cryptographic technology that provides fine-grained access control as well as data confidentiality. It enables one sender to encrypt the data for more receivers, and to specify a policy on who can decrypt the ciphertext using his/her attributes alone. However, most existing ABE schemes are constructed on bilinear maps and they cannot resist quantum attacks. In this paper, we propose a multi-authority CP-ABE (MA-CPABE) scheme on ideal lattices which is still secure in post-quantum era. On one hand, multiple attribute authorities are required when user's attributes cannot be managed by a central authority. On the other hand, compared with generic lattice, the ideal lattice has extra algebraic structure and can be used to construct more efficient cryptographic applications. By adding some virtual attributes for each authority, our scheme can support flexible threshold access policy. Security analysis shows that the proposed scheme is secure against chosen plaintext attack (CPA) in the standard model under the ring learning with errors (R-LWE) assumption.
In Ciphertext Policy Attribute-Based Encryption (CP-ABE) system, a set of attributes is associated with the private keys of each user. Also, the ciphertext is attached with a policy which is defined over that set of attributes. A user can decrypt the ciphertext if the ciphertext’s policy is satisfied by the attributes associated hith her private key. Traditional CP-ABE schemes, based on number theoretic problems, rely on a trustworthy central authority. But in many distributed applications it is expected that such authorities should be decentralized to avoid the risks of single-point failure. While the number theory-based hardness problems are prone to quantum attacks, lattice-based hardness problems can resist such attacks. In this paper, we construct a Decentralized Ciphertext-Policy Attribute-Based Encryption (DCP-ABE) scheme. Under this scheme, any participating entity can act as an authority by creating a public key. The athority utilizes the users’ attributes to generate the private keys for them. Any user can encrypt data in terms of any monotone access structure over attributes issued from any chosen set of authorities. Hence the protocol does not depend on any central authority. We utilize Learning With Errors over Rings (R-LWE) as the underlying hardness assumption for te protocol. The proposed post-quantum protocol achieves security under selective-set model whereby adversaries are allowed to corrupt any authority only statically through adaptive key queries.
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.
Abstract We address the problem of user fast revocation in the lattice-based Ciphertext Policy Attribute-Based Encryption (CP-ABE) by extending the scheme originally introduced by Zhang and Zhang [Zhang J, Zhang Z. A ciphertext policy attribute-based encryption scheme without pairings . In: International Conference on Information Security and Cryptology. Springer; 2011. p. 324–40. doi: https://doi.org/10.1007/978-3-642-34704-7_23 .]. While a lot of work exists on the construction of revocable schemes for CP-ABE based on pairings, works based on lattices are not so common, and – to the best of our knowledge – we introduce the first server-aided revocation scheme in a lattice-based CP-ABE scheme, hence being embedded in a post-quantum secure environment. In particular, we rely on semi-trusted “mediators” to provide a multi-step decryption capable of handling mediation without re-encryption. We comment on the scheme and its application, and we provide performance experiments on a prototype implementation in the Attribute-Based Encryption spin-off library of Palisade to evaluate the overhead compared with the original scheme.
In recent years, the research on ciphertext-policy attribute-based encryption (CP-ABE) scheme design based on learning with errors (LWE) has been a challenging problem, and many researchers have made a lot of attempts at it. At EUROCRYPT 2021, Datta, Komargodski, and Waters proposed the first provably secure direct CP-ABE construction that supports NC1 circuit access structures. Improving on their work, we propose a CP-ABE scheme. Technically, we use the new lattice two-stage sampling technique of Lai, Liu, and Wang (EUROCRYPT 2021) in the key generation phase instead of the extended trapdoor sampling technique. In this way, we obtain a CP-ABE scheme, which is at least as secure as the original scheme under the same conditions, and has a shorter ciphertext; we provide an innovative design idea for designing CP-ABE schemes only based on LWE, although this is only a partial theoretical work.