Attribute-based encryption is useful for one-to-many encrypted message sending. However, most attribute-based encryption schemes authorize and issue attributes to users by a single authority. Such a scenario conflicts with practical requirements and may cause the key-escrow problem. Hence, decentralization of authority is a critical issue in attribute-based encryption. Besides, dynamic membership management is another important issue in attribute-based encryption. With dynamic membership management, a system may update the user’s attributes without affecting other users, making the system more flexible and practical. On the other hand, with the rapid development of quantum computers nowadays, encryption schemes based on traditional mathematical problems are at the risk of quantum attacks. Among the existing quantum-resistant mathematical architectures, lattice-based cryptography is the most widely studied. Thus, we propose a multi-authority attribute-based encryption scheme with dynamic membership from lattices to solve the above problems. Moreover, we also formally prove the security of the proposed scheme under the decisional learning with errors assumption.
Attribute-based encryption is useful for one-to-many encrypted message sending. However, most attribute-based encryption schemes authorize and issue attributes to users by a single authority. Such a scenario conflicts with practical requirements and may cause the key-escrow problem. Hence, decentralization of authority is a critical issue in attribute-based encryption. Besides, dynamic membership management is another important issue in attribute-based encryption. With dynamic membership management, a system may update the user’s attributes without affecting other users, making the system more flexible and practical. On the other hand, with the rapid development of quantum computers nowadays, encryption schemes based on traditional mathematical problems are at the risk of quantum attacks. Among the existing quantum-resistant mathematical architectures, lattice-based cryptography is the most widely studied. Thus, we propose a multi-authority attribute-based encryption scheme with dynamic membership from lattices to solve the above problems. Moreover, we also formally prove the security of the proposed scheme under the decisional learning with errors assumption.
With the growing need for secure cloud storage and the threat of quantum attacks, we propose a post-quantum secure lattice-based multi-authority attribute-based multi-keyword searchable encryption scheme with dynamic membership. Based on the decisional learning with errors assumption, the proposed scheme resists quantum adversaries while supporting flexible multi-keyword search, decentralized authority to avoid key escrow, and dynamic attribute updates without affecting other users. It enables users to independently generate search tokens, allowing offline authorities and reducing communication overhead. Despite higher encryption costs, experimental results demonstrate that search and decryption remain efficient compared to existing post-quantum lattice-based solutions. The proposed scheme achieves strong data confidentiality and keyword privacy in the post-quantum setting.
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.
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.
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.
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.
Nowadays, emerging technologies such as smart terminals, cloud computing, and the Internet of Things are developing rapidly. The "One-to-one" encrypted transmission method is difficult to meet the communication needs in complex network environments due to high computational costs. Broadcast encryption technology can provide data encryption protection during information sharing among multiple users. However, most of the existing schemes are based on bilinear groups, which cannot resist quantum computing attacks. And these schemes also suffer from the key escrow problem. For this reason, a novel distributed broadcast encryption scheme is proposed based on the Learning with Errors (LWE) difficulty assumption on the lattice. The scheme avoids key interaction negotiation among users by introducing a public key bulletin board. Meanwhile, the scheme solves the security problem caused by the authoritative user's complete mastery of the user's private key.