Cloud-based services have powerful storage functions and can provide accurate computation. However, the question of how to guarantee cloud-based services access control and achieve data sharing security has always been a research highlight. Although the attribute-based proxy re-encryption (ABPRE) schemes based on number theory can solve this problem, it is still difficult to resist quantum attacks and have limited expression capabilities. To address these issues, we present a novel linear secret sharing schemes (LSSS) matrix-based ABPRE scheme with the fine-grained policy on the lattice in the research. Additionally, to detect the activities of illegal proxies, homomorphic signature (HS) technology is introduced to realize the verifiability of re-encryption. Moreover, the non-interactivity, unidirectionality, proxy transparency, multi-use, and anti-quantum attack characteristics of our system are all advantageous. Besides, it can efficiently prevent the loss of processing power brought on by repetitive authorisation and can enable precise and safe data sharing in the cloud. Furthermore, under the standard model, the proposed learning with errors (LWE)-based scheme was proven to be IND-sCPA secure.
Cloud-based services have powerful storage functions and can provide accurate computation. However, the question of how to guarantee cloud-based services access control and achieve data sharing security has always been a research highlight. Although the attribute-based proxy re-encryption (ABPRE) schemes based on number theory can solve this problem, it is still difficult to resist quantum attacks and have limited expression capabilities. To address these issues, we present a novel linear secret sharing schemes (LSSS) matrix-based ABPRE scheme with the fine-grained policy on the lattice in the research. Additionally, to detect the activities of illegal proxies, homomorphic signature (HS) technology is introduced to realize the verifiability of re-encryption. Moreover, the non-interactivity, unidirectionality, proxy transparency, multi-use, and anti-quantum attack characteristics of our system are all advantageous. Besides, it can efficiently prevent the loss of processing power brought on by repetitive authorisation and can enable precise and safe data sharing in the cloud. Furthermore, under the standard model, the proposed learning with errors (LWE)-based scheme was proven to be IND-sCPA secure.
The ciphertext-policy attribute-based proxy re-encryption (CP-ABPRE) scheme supports access control and can transform a ciphertext under an access policy to a ciphertext under another access policy without decrypting the ciphertexts, which is flexible and efficient for cloud sharing. The existing CP-ABPRE schemes are constructed by bilinear pairing or multi-linear maps which are fragile when the post-quantum future comes. This paper presents an efficient unidirectional single-hop CP-ABPRE scheme with small public parameters from a lattice. For the transformation between two access structures, they are required to be disjoint. This paper uses the trapdoor sampling technique to generate the decryption key and the re-encryption key in constructing the scheme, and uses the decompose vectors technique to produce the re-encrypted ciphertexts in order to control their noise. Finally, we extended the scheme to a unidirectional single-hop CP-ABPRE scheme with keyword search for searching the encrypted data. Both schemes were proved secure under the learning with errors assumption, which is widely believed to be secure in quantum computer attacks. To the best of our knowledge, our scheme is the first CP-ABPRE scheme based on the learning with errors assumption.
With the rapid development of quantum computing technology, data sharing systems in cloud storage may suffer from quantum computing attacks. Recently, many researchers have proposed encryption schemes to achieve quantum attack resistance and fine-grained data access control. However, single point of failure and secure attribute revocation are two critical problems for quantum-resistant encryption scheme in cloud storage environments. In order to deal with these problems, in this paper, we propose a revocable multi-authority attribute-based encryption from lattice (RMA-ABE-L) in cloud storage. Firstly, RMA-ABE-L scheme can achieve fine-grained data access control with quantum computing attack resistance. We design efficient anti-quantum algorithms based on R-LWE problem and merge them with ciphertext-policy attribute-based encryption (CP-ABE) structure. Secondly, RMA-ABE-L scheme can solve the single point of failure problem. We design the multi-authority structure to so that the compromise of some authorities does not affect the functioning of the whole data sharing system. Moreover, RMA-ABE-L scheme can realize secure attribute revocation. We design a secure attribute revocation mechanism and set special identity construction. The performance analysis shows that RMA-ABE-L scheme is more efficient than other related schemes.
Proxy re-encryption plays an important role for data security in cloud computing and big data, but the traditional re-encryption scheme based on the classical number theory problem cannot resist quantum attack, and the lattice-based cryptosystem has been proved to have the ability to resist quantum attack, so the lattice-based re-encryption scheme has always been a research hotspot. In view of the problem that collusion-resistance and multi-hop cannot be satisfied at the same time in existing schemes, this paper proposes a new identity-based proxy re-encryption scheme on lattice. Firstly, the scheme uses trapdoors as private keys to achieve one-way anti-collusion. In addition, we construct a variant of Learning with Errors (LWE), which uses a convert algorithm to transform the user matrix and replace the vector with a uniform matrix, so that the scheme can meet the requirements of multi-hop and encrypt multiple bits of messages at one time. Theoretical analysis and experimental simulation prove that the security of the new scheme can be reduced to a decision LWE problem, which can reach the IND-sID-CPA security in the standard model and can improve the encryption efficiency while ensuring the security.
To protect the privacy of cloud data, encryption before uploading provides a solution. However, searching for target data in ciphertext takes effort. Therefore, searchable encryption has become an important research topic. On the other hand, since the advancement of quantum computers will lead to the crisis of cracking traditional encryption algorithms, it is necessary to design encryption schemes that can resist quantum attacks. Therefore, we propose a multi-keyword searchable identity-based proxy re-encryption scheme from lattices. In addition to resisting quantum attacks, the proposed scheme uses several cryptographic techniques to improve encryption efficiency. First, identity-based encryption is used to reduce the computation and transmission costs caused by certificates. Second, the proposed scheme uses proxy re-encryption to achieve the purpose of outsourced computing, allowing the proxy server to reduce the computation and transmission costs of the users. Third, the proposed multi-keyword searchable encryption can provide AND and OR operators to increase the flexibility of searchability. Moreover, the access structure of the proposed scheme is not based on a linear secret sharing scheme (LSSS), avoiding the errors caused by an LSSS-based structure in decryption or search results. Finally, we also give formal security proof of the proposed scheme under the decisional learning with errors assumption.
Data is typically encrypted before transmission to a cloud server to safeguard user privacy. However, such encryption prevents the server from performing searches on the data, necessitating the introduction of novel cryptographic primitives, such as public key encryption with multi-ciphertext equality test (PKEMET). PKEMET allows the cloud server to execute a single equality test on multiple ciphertexts, determining if the underlying messages are identical disclosing any extra information. Ciphertext-policy attribute-based encryption (CP-ABE) facilitates secure and efficient data sharing in cloud computing environments by supporting fine-grained access control and flexible encryption. In this work, we integrate the concepts of PKEMET and CP-ABE, introducing a novel cryptographic primitive of CP-ABE with multi-ciphertext equality test (CP-ABEMET). We present the first quantum-resistant CP-ABEMET scheme based on the learning with errors (LWE) problem. This scheme enables the receiver to delegate the cloud server to perform a single equality test among multiple messages encrypted under distinct access policies. Importantly, during the multi-ciphertexts equality test, the server gains no knowledge of the encrypted messages. Furthermore, our proposed scheme not only achieves traditional indistinguishability against chosen plaintext attack (IND-CPA) and one-way against chosen plaintext attack (OW-CPA) security but is also proven to be number secure and resilient against collusion attacks. Finally, a comparative performance analysis between our CP-ABEMET and existing equality test schemes demonstrates that our approach is more practical, efficient, and secure.
The advent of quantum computing poses a significant threat to traditional cryptographic algorithms, including RSA, Diffie-Hellman, and Elliptic Curve Cryptography, due to the capabilities of quantum algorithms like Shor’s algorithm. Post-quantum cryptography (PQC) has emerged to address these challenges, with lattice-based cryptography (LBC) being a prominent candidate. LBC, underpinned by hard mathematical problems like Learning with Errors (LWE) and Ring-LWE (RLWE), offers robust security against quantum and classical adversaries. In parallel, Ciphertext-Policy Attribute-Based Encryption (CPABE) has become a critical tool for enabling fine-grained access control in data-sharing scenarios, such as secure cloud storage and IoT. While existing CP-ABE implementations rely on bilinear pairings vulnerable to quantum attacks, lattice-based CPABE schemes provide a quantum-resistant alternative. Despite their potential, these schemes face challenges in computational efficiency, collusion resistance, and implementation correctness. Our contributions include a detailed mathematical breakdown of one of the state-of-the-art (SOTA) lattice-based CP-ABE schemes and a novel correctness proof for the same scheme.