To ensure the privacy and security of the stored data, the data can be encrypted first and then stored on the cloud. However, it faces the problem that users cannot search keywords in a large amount of data, which limits the flexibility of file sharing in the cloud environment. Searchable encryption can effectively support users to retrieve encrypted data in the cloud. Public key searchable encryption (PEKS) is used to retrieve the target encrypted data by searching specific keywords. However, the development of quantum computers has led to attacks on conventional encryption algorithms, and it is necessary to design searchable encryption schemes that can resist quantum attacks. Therefore, we propose a lattice puncturable PEKS scheme. Besides resisting quantum attacks, the proposed scheme attains efficient and flexible user revocation. Firstly, identity-based encryption is employed to minimize the complexity of key management. Secondly, the puncturable encryption technology is integrated into the proposed encryption to revoke the decryption capability for selected messages, enabling authorized recipients to repeatedly update their decryption keys to retrieve the currently encrypted messages. Finally, we prove the security of our scheme under the indistinguishability against chosen keyword attack (IND-PUN-sID-CKA), and conduct a comparison with other schemes to emphasize its advantages. Although the scheme does not have an edge in size, it holds an advantage in key update after adding the puncture function and also realizes higher security.
To ensure the privacy and security of the stored data, the data can be encrypted first and then stored on the cloud. However, it faces the problem that users cannot search keywords in a large amount of data, which limits the flexibility of file sharing in the cloud environment. Searchable encryption can effectively support users to retrieve encrypted data in the cloud. Public key searchable encryption (PEKS) is used to retrieve the target encrypted data by searching specific keywords. However, the development of quantum computers has led to attacks on conventional encryption algorithms, and it is necessary to design searchable encryption schemes that can resist quantum attacks. Therefore, we propose a lattice puncturable PEKS scheme. Besides resisting quantum attacks, the proposed scheme attains efficient and flexible user revocation. Firstly, identity-based encryption is employed to minimize the complexity of key management. Secondly, the puncturable encryption technology is integrated into the proposed encryption to revoke the decryption capability for selected messages, enabling authorized recipients to repeatedly update their decryption keys to retrieve the currently encrypted messages. Finally, we prove the security of our scheme under the indistinguishability against chosen keyword attack (IND-PUN-sID-CKA), and conduct a comparison with other schemes to emphasize its advantages. Although the scheme does not have an edge in size, it holds an advantage in key update after adding the puncture function and also realizes higher security.
With the improvement of awareness of data privacy, the user's sensitive data are usually encrypted before uploading them to cloud. Searchable encryption is a critical technique on promoting secure and efficient cloud storage. In particular, publickey encryption with keyword search (PEKS) provides an elegant approach to achieve data retrieval in encrypted storage. All existing searchable publickey encryption schemes only provide the security based on classical cryptography hardness assumption. With the development of quantum computers, these schemes will be insecure. Based on the lattice hardness assumptions, we propose a new searchable publickey encryption scheme with a designated tester (dPEKS). Our scheme has advantages: First, our scheme is the first searchable publickey encryption scheme that is considered to be secure even if quantum computers are ever developed. Second, our scheme achieves the trapdoor indistinguishability. The trapdoor indistinguishability implies the security against outside offline keyword guessing attacks (KGAs). Last, our scheme can achieve the trapdoor anonymity for server.
With the improvement of awareness of data privacy, the user's sensitive data are usually encrypted before uploading them to cloud. Searchable encryption is a critical technique on promoting secure and efficient cloud storage. In particular, publickey encryption with keyword search (PEKS) provides an elegant approach to achieve data retrieval in encrypted storage. All existing searchable publickey encryption schemes only provide the security based on classical cryptography hardness assumption. With the development of quantum computers, these schemes will be insecure. Based on the lattice hardness assumptions, we propose a new searchable publickey encryption scheme with a designated tester (dPEKS). Our scheme has advantages: First, our scheme is the first searchable publickey encryption scheme that is considered to be secure even if quantum computers are ever developed. Second, our scheme achieves the trapdoor indistinguishability. The trapdoor indistinguishability implies the security against outside offline keyword guessing attacks (KGAs). Last, our scheme can achieve the trapdoor anonymity for server.
Searchable encryption enables efficient retrieval of encrypted data stored in cloud environments while preserving data confidentiality. Within this context, Public Key Encryption with Keyword Search (PEKS) allows data users to perform keyword-based searches using their public-private key pairs. However, traditional PEKS schemes remain vulnerable to Inside Keyword Guessing Attacks (IKGA), which led to the introduction of the Public-Key Authenticated Encryption with Keyword Search (PAEKS) paradigm to enhance resilience against insider threats. Despite this advancement, most existing PAEKS schemes rely on number-theoretic assumptions, such as the discrete logarithm problem, thereby becoming insecure in the presence of against quantum adversaries. Consequently, recent research has focused on developing quantum-resistant, lattice-based PAEKS schemes. Although schemes based on the Learning with Errors (LWE) problem provide strong post-quantum security, they often incur high computational and communication costs, limiting their practicality in large-scale cloud environments. To overcome these limitations, this work presents an efficient and verifiable PAEKS scheme based on the Middle-Product LWE (MP-LWE) problem, which preserves the underlying security guarantees while significantly improving performance. Formal security analysis demonstrates resistance against Chosen Keyword Attack (CKA) and IKGA in the random oracle (RO) model. Experimental results confirm that the proposed scheme achieves substantially lower computational and communication overheads compared to existing schemes, while maintaining robust post-quantum security.
Searchable encryption is a powerful tool that enables secure and private searches of encrypted data. It allows users to outsource their data to cloud servers while maintaining the confidentiality and privacy of their data. Password-authenticated symmetric searchable encryption (PASE) can help users avoid the complexity and security risks associated with key management while maintaining the advantages of searchable encryption. To the best of our knowledge, none of the existing PASE schemes can resist security threats in the post-quantum era, and there is an urgent need to design quantum-resistant solutions. However, post-quantum cryptography (e.g., lattice-based cryptography) varies significantly from traditional cryptography, and it is challenging to design a quantum-resistant PASE for cloud storage. In this work, we take the first step towards this challenge by proposing QPASE, a quantum-resistant password-authenticated symmetric searchable encryption for cloud storage. We employ lattice-based threshold oblivious pseudorandom function (TOPRF) to achieve password re-randomization and formally prove that QPASE is authentication secure and indistinguishability against chosen keyword attacks (IND-CKA) secure under quantum computers. QPASE can be extended to multi-keyword search and allows servers to update keys without affecting the users. The comparison results show that QPASE outperforms its foremost counterparts in security and computation overhead.
With the widespread development of database systems, data security has become crucial when it comes to sharing among users and servers. A straightforward approach involves using searchable encryption to ensure the confidentiality of shared data. However, in certain scenarios, varying user tiers are granted disparate data searching privileges, and administrators need to restrict the searchability of ciphertexts to select users exclusively. To address this issue, public key encryption with authorized keyword search (PEAKS) was proposed, wherein solely authorized users possess the ability to conduct targeted keyword searches. Nonetheless, it is vulnerable to resist quantum computing attacks. As a result, research focusing on authorizing users to search for keywords while achieving quantum security is far-reaching. In this paper, we propose a lattice-based variant of PEAKS (L-PEAKS) that enables keyword dataset authorization for outsourced data management. Unlike existing schemes, our design incorporates identity-based encryption (IBE) to overcome the bottleneck of public key management. Besides, we utilize several lattice sampling algorithms to defend against attacks from quantum adversaries. Specifically, each authorized user must obtain a search privilege from an authority. The authority distributes an authorized token to the user within a specific time period, and the user generates a trapdoor for any authorized keywords. Our scheme is proven to be secure against IND-sID-CKA and T-EUF security in a quantum setting. We also conduct comprehensive evaluations on a commodity machine to assess completeness and provide theoretical complexity comparisons with existing state-of-the-art schemes.
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.