Searchable Public Key Encryption Scheme Research Articles

Fast Keyword Search over Encrypted Data with Ciphertext in Cloud

At present times , it's accessible for people to store their data on clouds. To secure the privacy, people tend to encode their data before uploading them to clouds. Due to the wide use of cloud services, public key searchable encryption is necessary for users to search the encrypted files efficiently and rightly. still, the being public key searchable encryption schemes supporting monotonic queries suffer from either infeasibility in keyword testing or inefficiency similar as heavy computing cost of testing, large size of ciphertext or lattice, and so on. In this work, we first propose a novel and effective anonymous key- policy attribute- based encryption( KP- ABE). also by applying Shen etal.’s general construction to the proposed anonymous KP- ABE, we capture an effective and suggestive public key searchable encryption, which to the best of our knowledge achieves the best performance in testing among the existing similar schemes

Scan-free verifiable public-key searchable encryption supporting efficient user updates in distributed systems

Searchable encryption (SE) is a promising technology that provides search functions while preserving information privacy. A small number of SE schemes can be applied to a distributed system. In such systems, multiple owners provide data that is encrypted by their secret keys to the system for retrieval by users. In this setup, however, users need to scan a searchable index for retrievals, which leads to linear search complexity. Moreover, updates of users (e.g., revoking an expired user from the system) generally incur substantial overhead to re-build the index. Accordingly, we propose a scan-free verifiable public-key searchable encryption scheme with an efficient user update function in a distributed system (i.e., in a multi-owner multi-user model). First, owners self-select secret keys to encrypt keywords. A master secret key is designed to support keyword searches among these keys. Additionally, a searchable index with an implicit relationship between the same keyword is proposed. There is no need to scan the index for keyword retrieval, which achieves sub-linear search complexity. It is also important that the updates of owners do not exert an influence on users and the other owners in our proposed scheme. As the key revocation mechanism, the master secret key is split into more partial secret keys that are distributed to users. Accordingly, the system only needs to re-split and re-distribute the key rather than re-building the index for updates of users. When making queries, not only are the content of queries and the master secret key concealed, but collusion between some users and the cloud server is resisted. The proposed scheme also supports an efficient result verification mechanism. The security and utility of our scheme were confirmed thru analysis and evaluation.

A Public Key Searchable Encryption Method Based on Multiple Keywords

In recent years, the secure search of encrypted cloud data has become a hot research topic and a challenging task. Several secure search schemes have been proposed to address this challenge. However, existing public-key searchable encryption schemes still face many problems. Among these schemes, most of them are based on single-key searchable encryption schemes, and although some schemes are designed for multi-key search, they still disclose the secret information of the encrypted index. Based on this, this paper proposes a multi-key public-key searchable encryption scheme without a secure channel, which uses a random element padding method to construct an encrypted index to ensure the security of the index information, and then improves the efficiency of the search by aggregating the query keyword information to generate query trapdoors. The simulation results of the algorithm show that the algorithm improves the query efficiency and query accuracy under the condition that the index and trapdoor are secure.

An enhanced heterogeneous public key searchable encryption scheme supporting multiple keywords

Searchable encryption (SE) technology allows users to use keywords to retrieve encrypted data and ensure that useful plaintext information about encrypted data will not be disclosed. For a secure SE scheme, if it is able to meet the multi-trapdoor privacy (MTP), the security will be improved compared with the traditional SE scheme. However, there are few searchable encryption schemes that can meet the requirements of MTP. In addition to the security of the SE scheme, we should also strive to improve its practicability. Nowadays, many existing SE schemes use a single keyword to generate the keyword ciphertext and trapdoor for retrieving ciphertext, which will greatly reduce the accuracy of the search result. Another phenomenon deserves our attention. In recent years, public key cryptosystems such as certificateless cryptography (CLC) and public key infrastructure (PKI) have been widely used. If a SE scheme satisfies heterogeneity means that both sides of communication parties do not need to restrict the use of the same cryptosystems, the practicability of this scheme will be improved. Therefore, we propose a heterogeneous SE scheme that provides MTP. The new scheme supports multi-keyword search and allows the sender and receiver to be worked in different cryptosystems. Furthermore, it would obviously be impractical to use the same cryptographic system parameters between heterogeneous systems, so the communication parties in our scheme operate in different cryptosystems with different cryptographic system parameters. With the use of the random oracle model (ROM), we demonstrate the security of the proposed scheme, and we show the excellent performance of the proposed scheme at the end of the article.

Fast keyword search over encrypted data with short ciphertext in clouds

Nowadays, it is convenient for people to store their data on clouds. To protect the privacy, people tend to encrypt their data before uploading them to clouds. Due to the widespread use of cloud services, public key searchable encryption is necessary for users to search the encrypted files efficiently and correctly. However, the existing public key searchable encryption schemes supporting monotonic queries suffer from either infeasibility in keyword testing or inefficiency such as heavy computing cost of testing, large size of ciphertext or trapdoor, and so on. In this work, we first propose a novel and efficient anonymous key-policy attribute-based encryption (KP-ABE). Then by applying Shen et al.’s generic construction to the proposed anonymous KP-ABE, we obtain an efficient and expressive public key searchable encryption, which to the best of our knowledge achieves the best performance in testing among the existing such schemes. Only 2 pairings are needed in testing. By applying our searchable encryption, one is able to expressively and efficiently search their encrypted data on clouds, without leaking the keyword information. Besides, we also implement our scheme and others with Python for comparing the performance. From the implementation results, our scheme owns the best performance on testing, and the size of ciphertexts and trapdoors are smaller than most of the existing schemes.

An improved secure designated server public key searchable encryption scheme with multi-ciphertext indistinguishability

In the cloud, users prefer to store their sensitive data in encrypted form. Searching keywords over encrypted data without loss of data confidentiality is an important issue. In 2004, Boneh et al. proposed the first public-key searchable encryption scheme which allows users to search by the private key. However, most existing public-key searchable encryption schemes are vulnerable to keyword guessing attack and can not satisfy multi-ciphertext indistinguishability. In this paper, we construct a secure designated server public-key searchable encryption based on Diffie-Hellman problem. Our security analysis shows that our proposed scheme can resist against keyword guessing attack and provide multi-ciphertext indistinguishability for any adversity. Furthermore, the proposed scheme can achieve multi-trapdoor privacy for external attackers. Moreover, the simulation results between our scheme and previous schemes demonstrate our new scheme is suitable for practical application.

PPSEB: A Postquantum Public-Key Searchable Encryption Scheme on Blockchain for E-Healthcare Scenarios

In the current E-healthcare scenarios, medical institutions are used to encrypt the information and store it in an Electronic Health Record (EHR) system in order to ensure the privacy of medical information. To realize data sharing, a Public-key Encryption with Keyword Search (PEKS) scheme is indispensable, ensuring doctors search for medical information in the state of ciphertext. However, the traditional PEKS scheme cannot resist the keyword guessing quantum computing attacks, and its security depends on the confidentiality of the secret key. In addition, classical PEKS hand over the search process to a third party, affecting the search results’ accuracy. Therefore, we proposed a postquantum Public-key Searchable Encryption scheme on Blockchain (PPSEB) for E-healthcare scenarios. Firstly, we utilized a lattice-based cryptographic primitive to ensure the security of the search process and achieve forward security to avoid key leakage of medical information. Secondly, we introduced blockchain technology to solve the problem of third-party untrustworthiness in the search process. Finally, through security analysis, we prove the correctness and forward security of the solution in the E-healthcare scenarios, and the comprehensive performance evaluation demonstrates the efficiency of our scheme compared with other existing schemes.

Forward Secure Public Key Encryption with Keyword Search for Outsourced Cloud Storage

Cloud storage has become a primary industry in remote data management service but also attracts security concerns, where the best available approach for preventing data disclosure is encryption. Among them the public key encryption with keyword search (PKSE) is considered to be a promising technique, since clients can efficiently search over encrypted data files. That is, a client first generates a search token when to query data files, the cloud server uses the search token to proceed the query over encrypted data files. However, a serious attack is raised when PKSE meets cloud. Formally speaking, the cloud server can learn the information of a newly added encrypted data file containing the keyword that previously queried by using the search tokens it has received, and can further discover the privacy information. To address this issue, we propose a forward secure public key searchable encryption scheme, in which a cloud server cannot learn any information about a newly added encrypted data file containing the keyword that previously queried. To better understand the design principle, we introduce a framework for constructing forward secure public key searchable encryption schemes based on attribute-based searchable encryption. Finally, the experiments show our scheme is efficient.

An improved secure certificateless public-key searchable encryption scheme with multi-trapdoor privacy

An improved secure certificateless public-key searchable encryption scheme with multi-trapdoor privacy

Lightweight Searchable Public-Key Encryption with Forward Privacy over IIoT Outsourced Data

As more data from Industrial Internet of Things (IIoT) devices are been outsourced to the cloud, the need to ensure/achieve data privacy will be increasingly pressing. Searchable public-key encryption is a promising tool to achieve data privacy without sacrificing data usability. However, most existing searchable public-key encryption schemes are either inefficient (e.g., expensive in terms of encryption and searching keywords) or lack the required (security) features such as forward privacy. To address these limitations, we propose a lightweight searchable public-key encryption with forward privacy. Specifically, the scheme allows us to achieve forward privacy in a public-key cryptography (i.e., asymmetric) setting, and has the same search performance as a number of practical searchable symmetric encryption schemes. The formal security analysis shows that the proposed scheme is chosen-keyword attack resilient and achieves forward privacy. Finally, the experimental results on a real-world dataset demonstrate that the proposed scheme is highly efficient and scalable in IIoT applications.

An Efficient and Secure Public Key Authenticated Encryption With Keyword Search in the Logarithmic Time

Searchable encryption is an important cryptographic technique that achieves data security and keyword retrieval over encrypted data in cloud. In 2004, Boneh et.al proposed the first searchable encryption scheme based on asymmetric cryptography. Since then, many variants of public key searchable encryption schemes were proposed. However, most previous works are vulnerable to multi-ciphertext attack, and they cannot provide trapdoor indistinguishability. Another problem is how to improve the searching efficiency. To deal with two issues, we construct a fast and secure public key authenticated searchable encryption scheme with designed server. Our scheme can resist keyword guessing attacks, chosen multi-keyword attacks and multi-trapdoor attacks. The search function in our scheme achieves the logarithmic search time in number of keywords while most existing schemes required the linear time. By comparison with previous schemes in computational complexity, our scheme is very fast in keyword search.

An Efficient Pairing-Free Certificateless Searchable Public Key Encryption for Cloud-Based IIoT

The Industrial Internet of Things (IIoT), as a special form of Internet of Things (IoT), has great potential in realizing intelligent transformation and industrial resource utilization. However, there are security and privacy concerns about industrial data, which is shared on an open channel via sensor devices. To address these issues, many searchable encryption schemes have been presented to provide both data privacy-protection and data searchability. However, due to the use of expensive pairing operations, most previous schemes were inefficient. Recently, a certificateless searchable public-key encryption (CLSPE) scheme was designed by Lu et al. to remove the pairing operation. Unfortunately, we find that Lu et al.’s scheme is vulnerable to user impersonation attacks. To enhance the security, a new pairing-free dual-server CLSPE (DS-CLSPE) scheme for cloud-based IIoT deployment is designed in this paper. In addition, we provide security and efficiency analysis for DS-CLSPE. The analysis results show that DS-CLSPE can resist chosen keyword attacks (CKA) and has better efficiency than other related schemes.

A Blockchain-Based Searchable Public-Key Encryption With Forward and Backward Privacy for Cloud-Assisted Vehicular Social Networks

As the integration of the Internet of Vehicles and social networks, vehicular social networks (VSN) not only improves the efficiency and reliability of vehicular communication environment, but also provide more comprehensive social services for users. However, with the emergence of advanced communication and computing technologies, more and more data can be fast and conveniently collected from heterogeneous devices, and VSN has to meet new security challenges such as data security and privacy protection. Searchable encryption (SE) as a promising cryptographic primitive is devoted to data confidentiality without sacrificing data searchability. However, most existing schemes are vulnerable to the adaptive leakage-exploiting attacks or can not meet the efficiency requirements of practical applications, especially the searchable public-key encryption schemes (SPE). To achieve secure and efficient keyword search in VSN, we design a new blockchain-based searchable public-key encryption scheme with forward and backward privacy (BSPEFB). BSPEFB is a decentralized searchable public-key encryption scheme since the central search cloud server is replaced by the smart contract. Meanwhile, BSPEFB supports forward and backward privacy to achieve privacy protection. Finally, we implement a prototype of our basic construction and demonstrate the practicability of the proposed scheme in applications.

EFFICIENT AND EXPRESSIVE KEYWORD SEARCH OVER ENCRYPTED DATA IN CLOUD

Searchable encryption allows a cloud server to conduct keyword search over encrypted data on behalf of the data users without learning the underlying plaintexts. However, most existing searchable encryption schemes only support single or conjunctive keyword search, while a few other schemes that can perform expressive keyword search are computationally inefficient since they are built from bilinear pairings over the composite-order groups. In this paper, we propose an expressive public-key searchable encryption scheme in the prime-order groups, which allows keyword search policies i.e., predicates, access structures to be expressed in conjunctive, disjunctive or any monotonic Boolean formulas and achieves significant performance improvement over existing schemes. We formally define its security and prove that it is selectively secure in the standard model. Also, we implement the proposed scheme using a rapid prototyping tool called Charm and conduct several experiments to evaluate it performance. The results demonstrate that our scheme is much more efficient than the ones built over the composite-order groups. INDEX TERMS - Searchable encryption, cloud computing, expressiveness, attribute-based encryption

VCLPKES: Verifiable Certificateless Public Key Searchable Encryption Scheme for Industrial Internet of Things

Nowadays the data of the industrial Internet of Things (IIOT) have been stored in cloud servers. The security and privacy of stored data have been hot research topics. The technique of public key searchable encryption (PKSE) may contribute to protect the privacy of industrial data. It is extremely significant how to use PKSE to encrypted data and retrieve the encrypted data without revealing users’ private information. Meanwhile, most of the existing PKSE schemes do not consider the identity verification of the data owner who may upload bad ciphertext if he is malicious. In this paper, we firstly analyze the security of a certificateless searchable encryption scheme in the IIOT environment (Ma et al. scheme), and propose a feasible attack to demonstrate that their scheme is not secure. Through this attack, Type I adversary $A_{\mathrm {I}}$ can forge the trapdoor value for all keywords. Then we proposed a verifiable certificateless public key searchable encryption (VCLPKSE) scheme. The scheme not only overcomes the security issue of Ma et al. scheme, but also offers the authentications of data owners and data users. Via the authentication mechanism, data owners could not repudiate the fact they uploaded the ciphertext. Finally, we proved that the VCLPKSE scheme satisfies the ciphertext indistinguishability, trapdoor indistinguishability and unforgeability in the random oracle model. Meanwhile, we also do the simulation experiment to demonstrate the scheme’s efficiency.

Certificateless searchable public key encryption scheme secure against keyword guessing attacks for smart healthcare

The smart healthcare system (SHS) provides a new information service mode. It greatly improves the diagnostic efficiency by monitoring patients’ signs information via various wearable devices. To ensure the confidentiality of sensitive information, the security and privacy issues have drawn wide attention. The searchable encryption technology is suitable for addressing these issues, because it supports search over encrypted data and provides data privacy protection. Recently, many searchable public-key encryption (SPE) schemes have been designed to balance security and efficiency. However, these SPE schemes face the challenge of certificate management or key escrow. This is because they are constructed based on public key infrastructure (PKI) or identity (ID) cryptosystem. Meanwhile, most of SPE schemes are subject to great security threats, such as keyword guessing attacks (KGA). To resolve the above problems, this paper designs a secure certificateless SPE scheme for SHS, and this scheme does not require the use of secure channels, i.e., a SCF-CLSPE scheme. We prove that this SCF-CLSPE scheme can resist KGA and chosen keyword attacks (CKA) under standard model. In addition, the results of performance analysis indicate that this SCF-CLSPE scheme can achieve better efficiency.

NormaChain: A Blockchain-Based Normalized Autonomous Transaction Settlement System for IoT-Based E-Commerce

Internet of Things (IoT)-based E-commerce is a new business model that relies on autonomous transaction management on IoT-devices. The management system toward IoT-based E-commerce demands autonomy, lightweight, and legitimacy. As blockchain is an innovative technology that is competent in governing the decentralized network, we adopt it to design the autonomous transaction management system on IoT E-commerce. However, current blockchain solutions, most namely cryptocurrencies, have fatal drawbacks of nonsupervisability and huge computational overhead, and hence cannot be directly applied on IoT-based E-commerce. In this paper, we propose NormaChain, a blockchain-based normalized autonomous transaction settlement system for IoT-based E-commerce. By designing a special three-layer sharding blockchain network, we can significantly increase transaction efficiency and system scalability. Additionally, by designing an innovative decentralized public key searchable encryption scheme (decentralized public key encryption with keyword search (PEKS) scheme), we can uncover illegal and criminal transactions and achieve crime traceability. Our new decentralized PEKS scheme cryptographically eliminates the dependence of a trusted central authority in the original PEKS scheme and instead expands it to a fully decentralized governance, which distributes the supervision power equally among all parties. More importantly, by proving NormaChain is secure against chosen ciphertext attacks and against the stealing of the secret key, we show that NormaChain prevents a legitimate user’s privacy from being violated by banks, supervisors or malicious adversaries. Finally, we deliver the NormaChain system with design details and full implementations. Experiments show that the average transaction-per-second on IoT devices is around 113, and the supervision accuracy is 100% when proper target illegal keywords are provided.

Secure and Efficient Searchable Public Key Encryption for Resource Constrained Environment Based on Pairings under Prime Order Group

Searchable public key encryption scheme is a key technique for protecting data confidentiality in today’s cloud environment. Specifically, public key encryption with conjunctive and disjunctive keyword search (PECDK) can provide flexible search options without sacrificing keywords security and thus attracts a lot of attention nowadays. However, the most effective PECDK scheme is based on the inner product encryption (IPE), which needs more time and space cost. In this paper, by utilizing the bilinear pairing with a prime order group, we propose an efficient PECDK scheme needing less time and storage consumption. The proposed scheme is proven to be secure under a rigorous security definition. The theoretical analysis and experimental results demonstrate that our proposed scheme can significantly improve the time and space efficiency over the state-of-the-art scheme.

Security Analysis and Enhancement of a Certificateless Searchable Public Key Encryption Scheme for IIoT Environments

With the fast development of Industrial Internet of Things (IIoT), IIoT storage, which provides a lower cost, higher reliability of data, remote access services, and expandable storage space, is received much attention among enterprises and individual users. However, providing a secure IIoT storage service could be a challenging task for some situations, for example, how to search encrypted data in the IIoT. In this paper, we examine the security of a recent proposed certificateless searchable public key encryption scheme for IIoT environments by Ma et al. We find that their scheme is insecure against an off-line keyword guessing attack. Then, we propose an enhancement based on the scheme and prove the security of our enhancement with a formal model.

Searchable Public Key Encryption Supporting Semantic Multi-Keywords Search

Searchable public key encryption (SPE) that supports multi-keywords search, allows data users to retrieve encrypted files of interest efficiently, and thus it has been intensively studied during recent years. However, most existing SPE solutions focus on the exact keyword matching, which fails to capture the semantic information of documents. In this paper, we develop a novel SPE scheme supporting semantic multi-keywords search over the encrypted data. Our solution is mainly built on two techniques: one is a shallow neural network model called “word2vec” for capturing the semantic keywords from documents; the other is a keywords conversion method which can convert keywords into a set of vectors. We then utilize an efficient inner product encryption scheme to encrypt these converted vectors and develop the target SPE scheme, which is proven to be secure against chosen keywords attacks. Moreover, we also present both theoretical and experimental analysis to verify the efficiency and accuracy of this scheme. The experiments over a real-world dataset demonstrate that our scheme can obtain a practical performance in terms of time and space complexities. To the best of our knowledge, it is the first time to construct semantic keywords search scheme over encrypted data in the public key setting.