Dynamic Searchable Encryption Research Articles

SEDCPT: A secure and efficient Dynamic Searchable Encryption scheme with cluster padding assisted by TEE

Dynamic Searchable Symmetric Encryption (DSSE), which enables users to search and update encrypted data on an untrusted server without decryption, is a proven method when dealing with availability issues for outsourced data. However, the existing DSSE schemes suffer from forward and backward privacy problems. Although forward and backward privacy DSSE schemes can prevent these attacks, they still suffer from other challenges, such as count attacks, high communication overhead, and low computing efficiency. To solve the above problems simultaneously, we propose a secure and efficient dynamic searchable encryption scheme, which integrates a clustering algorithm, padding strategy, and trusted execution environments (TEE). The purpose of the scheme is to prevent count attacks while ensuring forward and backward privacy security. Our scheme also reduces the computing overhead and storage cost of the client by using TEE (e.g. Intel Software Guard Extension, Intel SGX) while maximizing the protection of client privacy. Furthermore, the scheme provides a secure hardware isolation environment for the cluster padding and search/update process to prevent malicious attacks from external software or super administrators. Finally, we provide corresponding security proofs and experimental evaluation which demonstrate both the security and efficiency of our scheme, respectively.

Efficient keyword search on encrypted dynamic cloud data

Sensitive information is increasingly being outsourced to the cloud. In order to protect the privacy of such sensitive data, cloud users (clients) encrypt their data before outsourcing. However, this poses a difficulty to later perform search operations on the encrypted data. Searchable encryption schemes enable a client to search and retrieve the cloud data (based on the keywords present in the data) when the data is encrypted. Dynamic searchable encryption schemes allow the client to search over the encrypted cloud data even when new documents are added to or deleted from the encrypted data. There is a trade-off between security (that is measured in terms of information leaked to the cloud) and the efficiency of dynamic searchable encryption schemes. Stronger security guarantees often come at a cost of less efficiency.In this work, we propose a new dynamic searchable encryption scheme for cloud data that achieves better security guarantees and improved efficiency compared to popular dynamic searchable encryption schemes. Our scheme uses an efficient data structure that reduces storage, lookup (search) time, and database modification time. We build a prototype of our scheme and experiment on large real-life datasets. We show our scheme performs better than the existing schemes, which provide similar (or weaker) security.

Block verifiable dynamic searchable encryption using redactable blockchain

To solve the problems of low efficiency, inflexible updates and the high storage cost of existing result verifiable searchable encryption schemes, we propose a dynamic searchable encryption scheme with block verification using redactable blockchain. First, the inverted index is divided into blocks, the verification tag corresponding to the block index is uploaded to the redactable blockchain, and smart contracts are used to perform block verification of the query results to improve the query and verification performance. Furthermore, we use the blockchain rewriting technology to update the tags in the result checklist, improving the data update performance and scalability of the blockchain, and ensuring the constant storage overhead of the blockchain. Security analysis confirms that our proposals guarantee the correctness and completeness of the query results. Experimental results show that our proposed approach can improve the query efficiency and result verification efficiency under the premise of the low-speed growth of the blockchain data scale. In particular, the advantages become more significant as the data collection scale grows.

A Searchable Encryption with Forward/Backward Security and Constant Storage

Dynamic searchable encryption satisfies users’ needs for ciphertext retrieval on semi-trusted servers, while allowing users to update server-side data. However, cloud servers with dynamically updatable data are vulnerable to information abuse and file injection attacks, and current public key-based dynamic searchable encryption algorithms are often complicated in construction and high in computational overhead, which is not efficient for practical applications. In addition, the client’s storage costs grow linearly with the number of keywords in the database, creating a new bottleneck when the size of the keyword set is large. To solve the above problems, a dynamic searchable encryption scheme that uses a double-layer structure, while satisfying forward and backward security, is proposed. The double-layer structure maintains a constant client-side storage cost while guaranteeing forward and backward security and further reduces the algorithm overhead by avoiding bilinear pairings in the encryption and decryption operations. The analysis results show that the scheme is more advantageous in terms of security and computational efficiency than the existing dynamic searchable encryption scheme under the public key cryptosystem. It is also suitable for the big data communication environment.

SEOT: Secure dynamic searchable encryption with outsourced ownership transfer

SEOT: Secure dynamic searchable encryption with outsourced ownership transfer

A Secure Personal Health Record Sharing System with Key Aggregate Dynamic Searchable Encryption

Recently, as interest in individualized health has increased, the Personal Health Record (PHR) has attracted a lot of attention for prognosis predictions and accurate diagnoses. Cloud servers have been used to manage the PHR system, but privacy concerns are evident since cloud servers process the entire PHR, which contains the sensitive information of patients. In addition, cloud servers centrally manage the PHR system so patients lose direct control over their own PHR and cloud servers can be an attractive target for malicious users. Therefore, ensuring the integrity and privacy of the PHR and allocating authorization to users are important issues. In this paper, we propose a secure PHR sharing system using a blockchain, InterPlanetary File System (IPFS), and smart contract to ensure PHR integrity and secure verification. To guarantee the patient’s authority over the management of his/her own PHR, as well as provide convenient access, we suggest a key aggregate dynamic searchable encryption. We prove the security of the proposed scheme through informal and formal analyses including an Automated Verification of Internet Security Protocols and Applications (AVISPA) simulation, Burrows–Abadi–Needham (BAN) logic, and security-model-based games. Furthermore, we estimate the computational costs of the proposed scheme using a Multiprecision Integer and Rational Arithmetic Cryptographic Library (MIRACL) and compare the results with those of previous works.

Forward privacy multikeyword ranked search over encrypted database

Dynamic searchable encryption (SE) aims at achieving varied search function over encrypted database in dynamic setting, which is a trade-off in efficiency, security, and functionality. Recent work proposes a file-injection attack which can successfully attack by utilizing some information leaked in the update process. To mitigate this attack, some SE schemes with forward privacy are proposed. However, these schemes are designed to achieve single keyword or conjunctive keyword search, which cannot support multikeyword search. Moreover, these schemes do not consider the function of results ranking. In this paper, we propose a forward privacy multikeyword ranked search scheme over encrypted database. We design a forward privacy multikeyword search scheme based on the classic MRSE scheme. Our scheme makes the cloud cannot obtain the actual match results of the past query with the newly updated files by adding the well-chosen dummy elements to the original index and query vectors. We rank the search results based on the matched keyword number and the T F × I D F $TF\times IDF$ rule in the dynamic setting. Our scheme uses only the symmetric encryption primitive. We implement our scheme for COVID-19 data set and the experimental evaluation results show that the proposed scheme is secure and efficient.

A Multi-User Forward Secure Dynamic Symmetric Searchable Encryption with Enhanced Security

A Multi-User Forward Secure Dynamic Symmetric Searchable Encryption with Enhanced Security

An Efficient Two-Server Ranked Dynamic Searchable Encryption Scheme

Searchable encryption (SE) allows users to search over encrypted data without decrypting. In most existing SE schemes, server returns all matched files without relevance ranking, and the update mechanism are suffering with high communication and computation cost, which are not efficient enough to satisfy the real-life dynamic scenario. Addressing the above issues, we proposed TS-RDSE—a Two-Server Ranked Dynamic Searchable Encryption scheme. We integrate orthogonal vector and efficient homomorphic encryption cryptosystems to build a vector-level dynamic secure index, which simultaneously supports efficient dynamic update operations like deletion and insertion of files flexibly. Moreover, in order to rank the search results by relevance without decryption, we build a secure sorting protocol based on the widely-used tf-idf weighting formula and addition property of partial homomorphic encryption, which achieves accurate sorting for the search results while protecting the privacy of relevance scores. We give a comprehensive analysis of the correctness of TS-RDSE in the aspect of searching and sorting with mathematical proofs. The security analysis shows that TS-RDSE is secure against adaptive dynamic chosen-keyword attacks (CKA2) by honest-but-curious adversaries in random oracle model. The performance analysis shows that TS-RDSE has both a very light user workload and a moderate server workload, and it is superior to the existing approaches in terms of functionalities and expansibility. Extensive experiments on the real-world dataset validate our analysis and show that TS-RDSE is suitable for the real world cloud storage environment.

Building a dynamic searchable encrypted medical database for multi-client

E-medical record is an emerging health information exchange model based on cloud computing. As cloud computing allows companies and individuals to outsource their data and computation, the medical data is always stored at a third party such as cloud, which brings a variety of risks, such as data leakage to the untrusted cloud server, unauthorized access or modification operations. To assure the confidentiality of the data, the data owner needs to encrypt the sensitive data before uploading to the third party. Yet, issues like encrypted data search, flexible access and control on sensitive data have also remained the most significant challenges. In this paper, we investigate a novel searchable encrypted e-medical framework for multi-client which provides both confidentiality and searchability. Different from previous privacy protecting works in secure data outsourcing, we focus on providing a fine-grained access control encrypted data search scheme including clients and data. Our scheme also enables secure data update of the encrypted database by leveraging a secure dynamic searchable encryption. Furthermore, we implement the proposed scheme based on some existed cryptography library, and conduct several experiments on a selected dataset to evaluate its performance. The results demonstrate that our scheme provides a balance between security and efficiency.

ID-based deletion searchable encryption scheme

Searchable encryption technology frees up user’s local storage resources and also facilitates user’s search on files in the server. At present, general searchable encryption schemes are merely static searches and cannot dynamically manipulate data already stored in server. In order to solve this problem, this paper proposes a dynamic searchable encryption scheme based on bilinear pairing, which can delete the specified identity file. When delete operation is performed, rights authentication is performed on user who issues delete request, and malicious deletion of illegal users is effectively prevented. At the same time, the security of the scheme is proved. Based on the implementation of delete function, the scheme achieves security against the choose plaintext attack.

Dynamic searchable encryption with privacy protection for cloud computing

SummaryThe dynamic searchable encryption schemes generate search tokens for the encrypted data on a cloud server periodically or on a demand. With such search tokens, a user can query the encrypted data whiles preserving the data's privacy; ie, the cloud server can retrieve the query results to the user but do not know the content of the encrypted data. A framework DSSE with Forward Privacy (dynamic symmetric searchable encryption [DSSE] with forward privacy), which consists of Internet of Things and Cloud storage, with the attributes of the searchable encryption and the privacy preserving are proposed. Compared with the known DSSE schemes, our approach supports the multiusers query. Furthermore, our approach successfully patched most of the security flaws related to the sensitive information's leakage in the DSSE schemes. Both security analysis and simulations show that our approach outperforms other DSSE schemes with respect to both effectiveness and efficiency.