Multi-keyword Searchable Encryption Research Articles

Implementation of A Blockchain-based Searchable Encryption for Securing Contact Tracing Data

<p>We developed a blockchain-based multi-keyword searchable encryption scheme for securing COVID-19 contact tracing data. In this scheme, we used AES-GCM to encrypt the contact tracing data, guaranteeing that only authorized users can perform decryption. Our scheme employed a Ciphertext-Policy Attribute-based searchable encryption to encrypt the search index, ensuring only users with appropriate attributes can perform search operations. The scheme supports dynamic updates of the search index. The blockchain-based storage with smart contract ensures immutability and non-repudiation of storage and retrieval. Overall, the evaluation of the scheme shows that it works efficiently without compromising the security goals. This is one of the first works to implement a solution for secure storage and search of contact tracing data with blockchain-based searchable encryption. Compared to the existing searchable contact tracing schemes, it provides more features and maintains efficiency even if a large search index is used.</p> <p> </p>

BMSE: Blockchain-based multi-keyword searchable encryption for electronic medical records

The storage of electronic medical records (EMRs) is an area of extensive research, and healthcare systems often delegate this task to cloud service providers (CSP). Typically, CSP transmits the encrypted EMRs to a cloud server with a searchable encryption scheme for easy retrieval. However, the enormous power held by centralized CSP poses a potential threat to patients’ personal privacy, as it can lead to unauthorized access and misuse of medical data by both CSP and data users, such as doctors. This paper proposes a blockchain-based multi-keyword searchable encryption (BMSE) electronic medical record solution. The scheme consists of two parts. On the one hand, our solution involves the integration of blockchain technology and the utilization of advanced encryption standard (AES) for symmetric data encryption. Additionally, we employ attribute-based encryption (ABE) to encrypt the search index. This approach aims to address the issue of excessive power held by centralized CSP, which can potentially result in the compromise of patients’ privacy. On the other hand, we use the K-means algorithm to cluster the documents, and use the relevance score of keywords and documents as the search index to solve the problem of low efficiency of the existing multi-keyword searchable encryption schemes. Finally, we verify the safety of BMSE through safety analysis, and the experimental analysis shows that BMSE improves the search efficiency.

A multi-keyword searchable encryption sensitive data trusted sharing scheme in multi-user scenario

Searchable encryption technology provides a solution for the trusted sharing of sensitive data. A large amount of encrypted data stored in data sharing servers can support keyword search without exposing data privacy, which has attracted more and more scholars’ attentions and researches. However, some multi-keyword searchable encryption schemes that deal with multi-semantic data still have security problems or low efficiency. To improve the security and efficiency of trusted sharing of sensitive data, we propose a multi-keyword searchable encryption scheme. The scheme designs a sensitive data sharing architecture based on blockchain technology, and the tamper-proof of distributed ledgers ensures the authenticity of encrypted data and indexes, as well as the supervision of sharing behaviors. On this basis, we improved the inverted index structure to achieve efficient multi-keyword searchable encryption while avoiding keyword-pair result pattern leakage. Our proposed scheme has passed formal security analysis, and simulation results show that the multi-keyword searchable encryption scheme is efficient.

Multi-Keyword Searchable Identity-Based Proxy Re-Encryption from Lattices

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.

VMSE: Verifiable multi-keyword searchable encryption in multi-user setting supporting keywords updating

Since the powerful storage capacity of the cloud platform, more and more people are willing to store their files on the cloud service provider (CSP). In order to prevent the privacy of outsourced files from being leaked, data owners will encrypt files before uploading. However, encryption will significantly limit the accurate location of the files. Therefore, this paper mainly introduces a verifiable multi-keyword searchable encryption scheme supporting keywords updating (VMSE). First of all, our proposed VMSE scheme can achieve multiple keywords search while protecting the privacy of the outsourced files and users. Then, our VMSE scheme can also implement the integrity verification and decryption of search results, which are not considered in many existing multi-keyword searchable encryption schemes. Currently, the dynamics in search schemes mostly refer to the dynamic update of outsourced files or user’s search permissions. We consider the keyword dynamic update of outsourced files in this paper, which is a design challenge for searchable encryption schemes and achieved by few searchable encryption schemes. Finally, performance evaluation shows our scheme is efficient and feasible in practical application.

A remote sensing encrypted data search method based on a novel double-chain

Remote sensing is considered to be a key technology for the development of smart cities. By analysing the data obtained by remote sensing, it is effective to manage and develop smart cities. However, with the rapid urbanisation and the increase in data capacity, how to store and retrieve remote sensing data which have more potential value and privacy with a more effective and safe method has become an imminent issue. In this paper, we propose an efficient verifiable and dynamic multi-keyword searchable encryption scheme for remote sensing data in smart cities. Moreover, we construct a double-chain index to support a multi-keyword search, where the Verification Index Chain is used to identify the users and the Keyword Index Chain is used to store the information of keywords. In addition, we adopt extended bitmap technology to realise update operations and verify the correctness and integrity of the search results. Experiments show that compared to the related existing schemes, the search time of the proposed scheme is reduced by 35% at most, the verification time is reduced by 14% at most and the update time is reduced by 57% at most.

Multi-keyword searchable encryption for smart grid edge computing

Searchable encryption scheme allows users to search for encrypted data containing some keywords without decrypting data. It protects the data privacy of data owners while promoting efficient data access. The searchable encryption scheme only supports a single keyword, which is easy to cause the problem of data redundancy. It makes users have to filter again in a large amount of data. In order to achieve the search goal more accurately, researchers proposed multi-keyword searchable encryption scheme. In addition, searchable encryption schemes that only support a single keyword are vulnerable to the disclosure of user access and search pattern. Based on these two reasons, we propose a searchable encryption scheme based on multi- keyword, which supports users to input more complex retrieval requests, and users can get a better sense of search experience. At the same time, it reduces the possibility of leakage of user access and search pattern to a certain extent. We also define the security model and prove that the scheme can resist the internal keyword guessing attack under the standard model. Finally, we also compare theoretical performance with other schemes and evaluate the experimental performance of our scheme.

A Lattice-Based Semantic Aware Multi-Keyword Searchable Encryption for Multi-User Environments

A Lattice-Based Semantic Aware Multi-Keyword Searchable Encryption for Multi-User Environments

Practical Multi-Keyword and Boolean Search Over Encrypted E-mail in Cloud Server

With the outbreak of e-mail message leakage events, such as the Hillary Clinton’s Email Controversy, privacy and security of sensitive e-mail information have become users’ primary concern. Encrypted email seems to be a viable solution for providing security, but it will greatly limit their operations. Public encryption with keyword search (PEKS) scheme is a popular technology to incorporate security protection and favorable operability functions together, which can play an important role in searching over encrypted email in a cloud server. In this paper, we propose a practical PEKS scheme named as public-key multi-keyword searchable encryption with hidden structures (PMSEHS). It could enable e-mail receivers to do the multi-keyword and boolean search in the large encrypted email database as fast as possible, without revealing more information to the cloud server. We also give comparative experiments, which demonstrate that our scheme has a higher efficiency in multi-keyword search for encrypted emails.

DMSE: Dynamic Multi-keyword Search Encryption based on inverted index

With the popularity of cloud storage, increasing people are willing to upload their files to cloud services. They will encrypt these files before uploading to protect the privacy of files. However, encryption makes effective search very difficult and inefficient. In this paper, we design a dynamic multi-keyword searchable encryption scheme on the encrypted cloud files, called DMSE. Firstly, the outsourced files in DMSE are pre-classified and preprocessed according to their privacy to achieve classified search. Secondly, based on the inverted index, DMSE realizes multiple keywords search, which protects the privacy of outsourced files and users and greatly improves the search efficiency. In addition, our DMSE extends the inverted index to the multi-DO/multi-DU scenario, which is the distinguishable difference between DMSE and other existing multi-keyword search schemes. Thirdly, our DMSE can further support the update of keywords to cope with the mismatch dilemma between the first extracted keywords and outsourced files, thus improving the practicality of DMSE scheme. Finally, comprehensive performance evaluation shows our DMSE scheme is effective and feasible in practical application.

Verifiable Multikeyword Search Encryption Scheme With Anonymous Key Generation for Medical Internet of Things

The development of the Internet of Things (IoT) has given birth to new applications and services. Accordingly, because the IoT application system collects a large amount of data containing sensitive information, there are also new challenges in data security and privacy preservation. To locate the medical IoT (mIoT), this article proposes a multikeyword searchable encryption scheme based on attributes supporting the data privacy preservation and integrity verification of the electronic health files stored on the IoT cloud platform on the basis of ensuring the application business functions of mIoT: 1) to ensure data confidentiality and fine-grained search authorization, the attribute-based encryption mechanism is introduced to encrypt the symmetric key. Moreover, anonymous key generation tampers semitrusted center authority’s (CA) decryption of all ciphertexts of users and access policy is hidden to prevent access policy from leaking; 2) the convergence key is adopted to encrypt electronic health records (EHRs), thereby providing double verification of the correctness of the search results and partial decryption results; 3) a time-division mechanism is also established to provide the access validity of shared EHRs; and 4) fixed length ciphertext and outsourcing decryption mechanisms are used to reduce the calculation on the user side, in which the majority of the decryption calculations are done by the cloud server. Formal proofs and performance evaluation show that the proposed scheme can achieve data security, keyword security, integrity verification, hidden policy, and collusion resistance, and has high computational efficiency and search efficiency.

A Multi-Keyword Searchable Encryption Scheme Based on Probability Trapdoor over Encryption Cloud Data

With the rapid development of cloud computing, massive data are transferred to cloud servers for storage and management savings. For privacy concerns, data should be encrypted before being uploaded. In the encrypted-domain (ED), however, many data computing methods working in the plain-domain are no longer applicable. Data retrieval has become a significant obstacle to cloud storage services. To break through this limitation, we propose a multi-keyword searchable encryption scheme by introducing probability trapdoors. Firstly, a keywords probability trapdoor is established to ensure that the scheme can resist indistinguishable attacks. Based on the keywords trapdoor, we present the keywords vector to make the scheme realize multi-keyword search in the process of data retrieval in the ED. Both security and performance analysis confirm the advantages of the proposed scheme in terms of search functionality and complexity.

Paillier-based Fuzzy Multi-Keyword Searchable Encryption Scheme with Order-Preserving

Efficient multi-keyword fuzzy search over encrypted data is a desirable technology for data outsourcing in cloud storage. However, the current searchable encryption solutions still have deficiencies in search efficiency, accuracy and multiple data owner support. In this paper, we propose an encrypted data searching scheme that can support multiple keywords fuzzy search with order preserving (PMS). First, a new spelling correction algorithm-(Possibility-Levenshtein based Spelling Correction) is proposed to correct user input errors, so that fuzzy keywords input can be supported. Second, Paillier encryption is introduced to calculate encrypted relevance score of multiple keywords for order preserving. Then, a queue-based query method is also applied in this scheme to break the linkability between the query keywords and search results and protect the access pattern. Our proposed scheme achieves fuzzy matching without expanding the index table or sacrificing computational efficiency. The theoretical analysis and experiment results show that our scheme is secure, accurate, error-tolerant and very efficient.

Multi-Keyword Searchable and Data Verifiable Attribute-Based Encryption Scheme for Cloud Storage

In a data sharing system, it is a basic requirement for a user, who has an appropriate privilege to perform keyword retrieval for encrypted documents stored in the cloud. Although traditional searchable encryption technology can provide data protection and retrieval characteristic, there are some main issues should also be considered. First, most existing attribute-based searchable encryption schemes only support single-keyword search, which may return abundant irrelevant search results, resulting in a waste of computational and broadband resources. Second, the user often needs to seek some data related to some particular keywords but his attributes may be altered frequently. Third, the cloud server is not completely loyal which sometimes returns a fraction of erroneous search results. Focus on these issues, a practical multi-keyword searchable encryption scheme is proposed for data integrity verification and attribute revocation by combining the ciphertext policy attribute-based encryption (CP-ABE) and auditing ideas. The scheme on one hand supports multi-keyword search which avoids the cloud server yield ample irrelevant documents by narrowing the search scope, and the other hand can implement effectively attribute revocation by entrusting ciphertext updates to the powerful cloud server, thereby preventing access by illegal users. Furthermore, third-party audits use verification algorithms to ensure the correctness of search results and reduce the amount of computing by end users. The most critically, the scheme proved to be resistant to selective plaintext attacks and selective keyword attacks under the general group model. The extensive experimental results demonstrate that the scheme is more expressive, efficient, and feasible in the practical applications.

A Multi-keyword Searchable Encryption Based on B+ Tree

The increasing maturity of cloud computing promotes the development of searchable encryption technologies. In order to improve the retrieval efficiency, a Multi-keyword Searchable encryption technology based on the B+ tree is proposed in this paper. Establish indexes and retrieval trapdoor by using the space vector model and sort retrieved results according to the relevance score and the keyword matching. Experiments are carried out on real data sets, and the results show that the proposed scheme has high retrieval efficiency.

DMRS: an efficient dynamic multi-keyword ranked search over encrypted cloud data

With the rise of cloud computing, data owners outsource their data to public cloud servers while allowing users to search the data, aiming at greater flexibility and economic savings. For privacy considerations, private data must be encrypted before outsourcing, and this makes the method of plaintext keyword search infeasible. However, it is critical to enable encrypted data able to be searched. Considering the requirements of practical application scenarios, the function of efficient multi-keyword ranked search and similarity search based on relevance score is necessary for data users. There proposed a number of multi-keyword searchable encryption schemes to try to meet this demand. However, most existing schemes do not satisfy required dynamic update simultaneously. In this paper, a novel and efficient dynamic multi-keyword ranked search scheme improved from traditional secure kNN computation is proposed. The proposed scheme incorporates the similarity measure “coordinate matching” and “inner product similarity” to improve the relevance of search keywords to the relevant cloud files. A reverse data structure is introduced to allow users to perform dynamic operations on document collection, either inserting or deleting. The sparse matrix is used to replace the dense large-scale matrix in index encryption and query vector encryption to improve efficiency. Experiments show that the proposed scheme indeed reduces the overhead of computation and storage compared to MRSE scheme, concurrently guaranteeing privacy and efficiency.