—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.
—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.
Abstract—Sahai and Waters introduced a fuzzy id-based encryption (FIBE) scheme in which an identity was viewed as a set of descriptive attributes, and any user with a private key for an identity ID was allowed to decrypt a ciphertext encrypted with an identity ID ′ , if and only if the identity ID and ID ′ were close to each other as measured by the “set overlap ” distance metric. After that, Shweta Agrawal, Xavier Boyen, Vinod Vaikuntanathan, Panagiotis Voulgaris and Hoeteck Weeto constructed a fuzzy id-based encryption scheme from the hardness of the Learning With Errors ( LWE) problem. The two schemes both had more longer public and private keys, and it was not very efficient. This paper gives more efficient fuzzy id-based encryption scheme from lattice, in which the public keys are greatly reduced, and there are two vectors corresponding to each bit of the identity by using of the algorithm Sampleleft introduced by Shweta Agrawal, Dan Boneh and Xavier Boyen, and only a trapdoor basis is the secret key. Furthermore, the scheme is dealing with N bit − information and is also secure from the hardness of the Learning With Errors ( LWE) problem, and all these greatly raise efficiency.
Access control can selectively restrict access to sensitive information stored by third-party sites on the Internet. Attribute-based encryption (ABE) schemes can strengthen the effective combination of flexibility and operability of access control. They allow one sender to encrypt a message for more than one recipient, and to specify who should be able to decrypt, using attributes alone. Since 2005, many powerful ABE schemes have been presented, but there are two types of problem that haven't be efficiently resolved so far. On the one hand, as practical extension of identity-based encryption (IBE) schemes, ABE schemes are also confronted with key escrow problem. On the other hand, attribute set belonging to one user is usually monitored by different authorities in this era of collaboration. Multi-authority ABE (MA-ABE) schemes can simultaneously resolve these problems, but now they have not been thoroughly investigated yet. More precisely, MA-ABE schemes against quantum attack are the main barrier of the development of ABE schemes in a 'post-quantum' world. In this paper, we firstly present a MA-ABE scheme from lattices, in which identities of users are authenticated by a central authority, which improves the efficiency of authentication. Furthermore, different attribute private keys are still distributed by different authorities, and the central authority cannot obtain any secret information of other attribute authorities, which resolves key escrow problem to some extent. In MAABE, attribute private keys belonging to one user are generated by different authorities, and how to ensure correct decryption is one of the crux of schemes. Our scheme gives a simple solution, and each user's attribute private keys are combined using sharing of common public information to automatically realize correct decryption. To our best knowledge, this is the first MA-ABE scheme from lattices, and it is more efficient than the MA-ABE presented by Melissa Chase. Finally, we present a multi-authority large universe ABE scheme, in which the sizes of the public key and the ciphertext are only relative to the number of the attribute authorities, and a user will be able to decrypt a ciphertext if and only if he has at least tK attributes from each authority K.
With quantum computing, traditional methods of encryption have become insufficient. This has led to the need for a transition to more reliable and flexible encryption systems. In this context, we examine the latest approaches to attribute-based encryption ABE schemes based on lattice cryptography and hybrid ones that combine symmetric encryption with public key ABE. These systems give post-quantum security in addition to fine-grained control, adaptive policy dynamic enforcement, and multi-level hierarchical control. We examine the most significant gaps regarding revocation, multi-authority frameworks, and ciphertext-controlled policies using LWE and Ring-LWE. Text length, key management complexity, and system interoperability are practical concerns too. A comparative analysis of five schemes shows each one's strengths and weaknesses. Designating the encryption phase speeds up the key generation process, so we implemented a multithreaded structure to address some of the identified performance constraints. This worked with other researchers designing robust quantum-access-controlled systems.
Attribute-based encryption (ABE) has been an active research area in cryptography due to its attractive applications. But almost all attribute-based encryption schemes are based on bilinear maps, which leave them vulnerable to quantum cryptanalysis. The lattice-based ABE schemes from the Learning with errors (LWE) have appeared, but they are not efficient enough for practical applications. Thus we propose an efficient attribute-based encryption based on the Learning with errors over Rings (R-LWE), which is called ABER-LWE. The security analysis shows that ABER-LWEscheme is secure in the selective-set model under the R-LWE assumption, whose security can reduce to the hardness of the shortest vector problem in the worst case on ideal lattices. The efficiency analysis indicates that ABER-LWEis more efficient than previous ABE cryptosystems on lattices.
The recent promising results on the hardness of lattice problems have inspired the construction of several Attribute-based Encryption (ABE) schemes from the quantum resistant perspective. However, these schemes are insufficient enough for supporting real-world applications due to inherent quadratic overhead problem in the use of Learning With Error (LWE). To solve this problem, this paper proposed a Ciphertext-Policy Attribute-Based Encryption (CP-ABE) scheme from a more lightweight ideal lattice classes- Ring-Learning with Errors (Ring-LWE), that further called as CP-ABER-LWEscheme. Compared to existing R-LWE based ABE scheme, the proposed CP-ABER-LWEis capable to handle a monotone access structure and enjoys collusion resistance properties. We exploited Linear Secret Scheme (LSSS) to express a monotone access structure. For resist to collusion attack, we applied the private key randomization technique to blind the user's private key. The proposed scheme CP-ABER-LWEis further proven to be secure under the Decision Ring-LWEd,q,χproblem in the selective set model.
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.