Bilinear Diffie-Hellman Assumption Research Articles

Public-Key Authenticated Encryption with Keyword Search Made Easy

Public-key searchable encryption allows keyword-associated tokens to be used to test if a ciphertext contains specific keywords. Due to the low entropies of keywords, the token holder can create ciphertexts from candidate keywords and test them using the token in hand to recover the keywords, known as inside keyword guessing attacks (IKGA). Public-key authenticated encryption with keyword search is a searchable encryption proposed to defend against such attacks. It ensures the sender's private key protects the ciphertexts from the IKGA. PAEKS schemes with reasonable security and practical efficiency remain elusive despite many proposals. This work provides a simple generic PAEKS scheme from non-interactive key exchange (NIKE) and symmetric-key equality-predicate encryption with three new constructions for the latter, respectively from pseudorandom functions (PRFs), the decision bilinear Diffie-Hellman assumption, and the learning-with-errors assumption. Instantiating our generic scheme, we derive several PAEKS schemes from the most well-known assumptions, with some of them achieving full cipher-keyword indistinguishability and full token indistinguishability in the standard model, for the first time. Our instantiated schemes allow practical implementations and outperform the existing PAEKS schemes under the same assumptions.

Secure personal-health-records searching in edge-based Internet of Medical Things through plaintext checkable encryption

The security of Personal Health Records (PHRs) within the Internet of Medical Things (IoMT) infrastructure is a pressing issue in the healthcare sector. Edge-based IoMT devices like smart wearables and implantables often acquire PHRs. Cloud computing plays a vital role in handling computing and storage tasks for edge-based IoMT devices. However, concerns about trust with cloud servers require the use of encryption, which may complicate the retrieval of encrypted PHRs from the cloud. This paper presents certificateless public key encryption with plaintext-checkable encryption (CL-PKE-PCE). CL-PKE-PCE enables searching for encrypted data using plaintext keywords while eliminating key escrow and certificate management issues. The CL-PKE-PCE scheme facilitates the verification of ciphertexts against plaintexts without the need for decryption, thereby maintaining data privacy. Furthermore, the security of the proposed CL-PKE-PCE scheme has been substantiated under the bilinear Diffie–Hellman assumption. Compared to similar work, it efficiently lowers calculation costs for encryption, decryption, and search algorithms by 63.66%, 51.17%, and 61.62%, respectively. The findings demonstrate that the CL-PKE-PCE is simultaneously secure and efficient, affirming its suitability for edge-based IoMT scenarios.

Proxy re-encryption with plaintext checkable encryption for integrating digital twins into IIoT

Digital Twin (DT) technology has emerged as a robust mechanism for overseeing and improving the lifecycle processes of the Industrial Internet of Things (IIoT) by creating their virtual counterparts. The widespread employment of cloud computing is apparent in delivering computational and storage services for the DT within the IIoT environment. Ensuring the confidentiality of DT data is crucial since data owners, cloud service providers, and users operate across separate trust domains. Accordingly, public key encryption is a viable solution for managing access. However, traditional public key encryption encounters challenges in achieving effective search and secure sharing of encrypted DT data in the cloud. This paper introduces a proxy re-encryption scheme with plaintext checkable encryption for data access control (PRE-IBSC-PCE), which addresses the challenges associated with searching for and sharing encrypted digital twin data in the cloud. The PRE-IBSC-PCE achieves efficient data search and sharing while ensuring privacy, integrity, non-repudiation, and authenticity. Meanwhile, we prove that PRE-IBSC-PCE is secure under the decisional bilinear Diffie–Hellman assumption in the random oracle model. Lastly, when compared to similar schemes, the performance analysis of the PRE-IBSC-PCE is more efficient and suitable for DT applications in IIoT.

CONTROL CLOUD DATA ACESS PRIVELAGE AND ANONYMITY WITH FULLY ANONYMOUS ATTRIBUTE BASED ENCRYPTION

Cloud computing is a revolutionary computing paradigm, which enables flexible, ondemand, and low-cost usage of computing resources, but the data is outsourced to some cloud servers, and various privacy concerns emerge from it. Various schemes based on the attribute-based encryption have been proposed to secure the cloud storage. However, most work focuses on the data contents privacy and the access control, while less attention is paid to the privilege control and the identity privacy. In this paper, we present a semi-anonymous privilege control scheme AnonyControl to address not only the data privacy, but also the user identity privacy in existing access control schemes. AnonyControl decentralizes the central authority to limit the identity leakage and thus achieves semianonymity. Besides, it also generalizes the file access control to the privilege control, by which privileges of all operations on the cloud data can be managed in a fine-grained manner. Subsequently, we present the AnonyControl-F, which fully prevents the identity leakage and achieve the full anonymity. Our security analysis shows that both AnonyControl and AnonyControl-F are secure under the decisional bilinear Diffie–Hellman assumption, and our performance evaluation exhibits the feasibility of our schemes.

Multiauthority Attribute-Based Encryption for Assuring Data Deletion

In order to alleviate key escrow issue, the notion of multiauthority attribute-based encryption (MA-ABE) was presented, which was widely applied in cloud storage environment. In data sharing environment, secure data deletion is very crucial and challenging issue. Hence, in this article, we concentrate on verification of data deletion operation, i.e., assuring data deletion. To solve this problem, we put forward a system model, formal definition and security model of MA-ABE for assuring data deletion. Furthermore, we design a MA-ABE scheme for assuring data deletion, which is more practicable than the single authority ABE scheme. The designed scheme not only overcomes key escrow issue, but also resists collusion attack between malicious user and unauthorized user. In addition, our scheme utilizes merkle hash tree to obtain verifiable data deletion. Based on decisional bilinear Diffie-Hellman (DBDH) assumption, the scheme is proven to be secure under the selective-policy model. The experimental result indicates that the designed scheme is efficient for practical application.

Authenticated Key Exchange Protocol in the Standard Model under Weaker Assumptions

A two-party authenticated key exchange (AKE) protocol allows each of the two parties to share a common secret key over insecure channels, even in the presence of active adversaries who can actively control and modify the exchanged messages. To capture the malicious behaviors of the adversaries, there have been many efforts to define security models. Amongst them, the extended Canetti–Krawczyk (eCK) security model is considered one of the strongest security models and has been widely adopted. In this paper, we present a simple construction of a pairing-based eCK-secure AKE protocol in the standard model. Our protocol can be instantiated with a suitable signature scheme (i.e., an existentially unforgeable signature scheme against adaptive chosen message attacks). The underlying assumptions of our construction are the decisional bilinear Diffie–Hellman assumption and the existence of a pseudorandom function. Note that the previous eCK-secure protocol constructions either relied on random oracles for their security or used somewhat strong assumptions, such as the existence of strong-pseudorandom functions, target collision-resistant functions, etc., while our protocol construction uses fewer and more-standard assumptions in the standard model. Furthermore, preserving the same security argument, our protocol can be instantiated with any appropriate signature scheme that comes in the future with better efficiency.

Revocable Certificateless Public Key Encryption with Equality Test

Traditional public key cryptography requires certificates as a link between each user’s identity and her/his public key. Typically, public key infrastructures (PKI) are used to manage and maintain certificates. However, it takes a lot of resources to build PKI which includes many roles and complex policies. The concept of certificateless public key encryption (CL-PKC) was introduced to eliminate the need for certificates. Based on this concept, a mechanism called certificateless public key encryption with equality test (CL-PKEET) was proposed to ensure the confidentiality of private data and provide an equality test of different ciphertexts. The mechanism is suitable for cloud applications where users cannot only protect personal private data but also enjoy cloud services which test the equality of different ciphertexts. More specifically, any two ciphertexts can be tested to determine whether they are encrypted from the same plaintext. Indeed, any practical system needs to provide a solution to revoke compromised users. However, these existing CL-PKEET schemes do not address the revocation problem, and the related research is scant. Therefore, the aim of this article is to propose the first revocable CL-PKEET scheme called RCL-PKEET which can effectively remove illegal users from the system while maintaining the effectiveness of existing CL-PKEET schemes in encryption, decryption, and equality testing processes. Additionally, we formally demonstrate the security of the proposed scheme under the bilinear Diffie-Hellman assumption.

Non-interactive Boolean Searchable Asymmetric Encryption With Bilateral Access Control

Abstract Searchable asymmetric encryption (SAE) enables a client to search over a data owner’s encrypted data. Nevertheless, state-of-the-art SAE schemes allow a data owner to specify access control policy for a client, while they have not considered the threat case of a malicious data owner. To address the problem, this work presents a non-interactive SAE scheme with bilateral access control: (i) allowing data owner and client to both specify policies toward the other party; (ii) allowing client to perform arbitrary boolean queries with sub-linear search complexity. Technically, we extend Cash et al.’s highly scalable SSE into an asymmetric setting and introduce the property of data owner authenticity. By refining identity-based matchmaking encryption, we formalize the syntax and security definition of our SAE with identity-based bilateral access control. Moreover, the security of the proposed SAE can be reduced to discrete logistic assumption and decisional bilinear Diffie–Hellman assumption. As an enhanced extension, we present a non-interactive multi-client SAE scheme with fuzzy identity-based bilateral access control. In addition, we implement the proposed schemes in real cloud platform and evaluate their performance on a real-world dataset. The result confirms that our SAE schemes achieve bilateral access control for both data owner and client with highly acceptable efficiency.

Outsourcing multiauthority access control revocation and computations over medical data to mobile cloud

With recent advances in cloud computing, mobile devices are increasingly being used to record patient physiological parameters, and transfer them to a cloud-based hospital information system, for access control mediation over a variety of stakeholders. In such a cloud-based architecture, the patient must specify an access policy for a group of authorized parties towards its outsourced data. Multiauthority ciphertext-policy attribute-based encryption (CP-ABE) was provided as an innovative cloud-based access control cryptographic primitive to tackle the key escrow issue in a centralized architecture, and boost flexibility through cross-domain attributes management. Existing works, however, still have glaring drawbacks. First, they still rely on a trusted authority to generate and distribute user secret keys. Second, they do not simultaneously provide encryption, decryption, or revocation outsourcing, resulting in high processing and communication cost for both the data sender and the data receiver. Third, they do not support both user and attribute revocation, and the integrity of ciphertext downloaded from the cloud is not always verified at the user end. As a result, this paper exploits the dummy attribute technique and introduces a novel, efficient, and secure multiauthority ciphertext-policy ABE method for mediating access control over medical data, in the mobile cloud. The ciphertext access policy enforcement, partial ciphertext decryption, and both the user and attribute indirect revocation updates are safely outsourced to the cloud server in this study. Theoretical analysis demonstrates that our scheme is efficient and verifiable, and we prove that our construction is secure under the decisional bilinear Diffie-Hellman assumption.

Identity-Certifying Authority-Aided Identity-Based Searchable Encryption Framework in Cloud Systems

In the era of cloud computing, massive quantities of data are encrypted and uploaded to the cloud to realize a variety of applications and services while protecting user confidentiality. Accordingly, the formulation of methods for efficiently searching encrypted data has become a critical problem. Public-key encryption with keyword search is an efficient solution that allows the data owner to generate encrypted keywords for a given document while also allowing the data user to generate the corresponding trapdoor for searching. Huang and Li proposed a public-key authenticated encryption with keyword search (PAEKS) scheme to resist keyword guessing attacks, where the data owner not only encrypts keywords but also authenticates them. However, existing PAEKS-related schemes carry a tradeoff between efficiency, storage cost, and security. In this article, we introduce a novel framework called identity-certifying authority-aided identity-based searchable encryption, which has the advantage of reducing storage space while remaining the efficiency and security. We formally define the system model and desired security requirements to represent attacks in a real scenario. In addition, we propose a provably secure scheme based on the gap bilinear Diffie–Hellman assumption and experimentally evaluate our scheme in terms of its performance and theoretical features against its state-of-the-art counterparts.

An Efficient Revocable Identity-Based Encryption with Equality Test Scheme for the Wireless Body Area Network

With the rapid development and popularization of cloud computing, people are willing to upload their own data to the cloud to enjoy the services. However, some personal and private data are not suitable for uploading directly to the cloud. Therefore, these data must be encrypted before uploading to the cloud to ensure the confidentiality. To achieve the confidentiality of data and enjoy cloud services, a notion of identity-based encryption with equality test (IBEET) was proposed. Using IBEET, two ciphertexts encrypted under different public keys can be tested to confirm whether they contain the same plaintext. The equality test can be applied to the wireless body area network system in which the cloud can utilize ciphertexts from patients and medical institutions to perform equality tests to determine whether which patient’s status is abnormal. Indeed, revoking illegal or expired users on any cryptosystem is an important issue. To the best of our knowledge, there is little research on the design mechanism of user revocation in the IBEET. In this paper, we propose a novel notion of revocable identity-based encryption with an equality test, called RIBEET. Based on the notion, we present the first RIBEET scheme. Meanwhile, the proposed scheme will be proven to be secure under the bilinear Diffie-Hellman (BDH) assumption.

Attribute-Based Private Data Sharing With Script-Driven Programmable Ciphertext and Decentralized Key Management in Blockchain Internet of Things

In this article, we address the problem of secure sensitive data sharing for the specified recipients in Blockchain Internet of Things (BIoT). To do it, we present a cryptographic solution to meet the requirements of decentralization and convenience through key management and programmable ciphertext. First, we design a new ciphertext-policy decentralized-key attribute-based encryption (CP-DK-ABE) scheme. After the master secret key is shared into all full nodes in the form of threshold secret sharing, a decentralized multiparty computation protocol is used to generate the user’s private key in an interactive way. Meanwhile, the attribute subkeys associated with the private key can be reconstructed by obtaining a fragment from each of full nodes, so as to achieve the cooperative management of attribute key through all of full nodes. Furthermore, following the blockchain’s script system, we introduce five new opcodes to represent ciphertext in the programmable format. Such a mechanism provides flexible capability to represent the logical relationship of the access control policy among attribute subciphers in the CP-DK-ABE ciphertext by the scripting language. As a result, the processes of encryption and decryption are implemented entirely by the script interpreter on the blockchain node, thereby greatly improving the convenience of programming in BIoT devices. In addition, we prove that the proposed CP-DK-ABE scheme is key private and semantically secure for a limited number of corrupted full nodes under the decisional linear and bilinear Diffie–Hellman assumption, respectively.

Identity-Based Encryption With Continuous Leakage-Resilient CCA Security From Static Complexity Assumption

Abstract Although a large number of provably secure cryptographic primitives have been proposed in the literature, many of these schemes might be broken in practice because of various leakage attacks. Therefore, the leakage resilience should be considered in designing these primitives. However, in identity-based cryptography, most of the existing leakage-resilient identity-based encryption (IBE) schemes suffer some limitations: they either resist the leakage attacks in the selective identity security model or achieve the chosen-ciphertext attack (CCA) security based on a non-static assumption. In this paper, an IBE scheme with adaptive leakage-resilient CCA security is proposed, and its security is rigorously proved in the random oracle model under a classic static complexity assumption, e.g. decisional bilinear Diffie–Hellman assumption. In our construction, all elements of ciphertext are randomly distributed in the adversary’s view. Hence, the adversary cannot obtain any useful information of the user’s private key from the given ciphertexts. Moreover, a unique property of our construction is that the leakage parameter is independent of the plaintext space, which contributes a better leakage rate.

Self-Verifiable Attribute-Based Keyword Search Scheme for Distributed Data Storage in Fog Computing With Fast Decryption

Presently many searchable encryption schemes have been proposed for cloud and fog computing, which use fog nodes (or fog servers) to partly undertake some computational tasks. However, these related schemes still retain cloud servers to undertake most computational tasks, which result in large communication costs between edge devices and cloud servers. Therefore, in this paper we propose a self-verifiable attribute-based keyword search scheme for distributed data storage (SV-KSDS) in full fog computing, where each decryption operation on the data required by a user must meet the negotiated decryption rule between fog servers. Our SV-KSDS scheme first provides attribute-based distributed data storage among fog servers through the <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$(w, \sigma)$ </tex-math></inline-formula> threshold secret-sharing scheme, where fog servers can provide self-verifiable keyword search and data decryption for terminal users. Compared with the data storage in cloud computing, our scheme extends it to the distributed structure while providing fine-grained access control for distributed data storage through attribute-based encryption. The access control policy of our scheme is constructed on linear secret-sharing scheme, whose security is reduced to the decisional bilinear Diffie-Hellman assumption against chosen-keyword attack and the decisional <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${q}$ </tex-math></inline-formula> -parallel bilinear Diffie-Hellman assumption against chosen-plaintext attack in the standard model. Based on theoretical analysis and practical testing, our SV-KSDS scheme generates less computation and communication costs, which further unloads some computational tasks from terminal users to fog servers so as to reduce computing costs of terminal users.

Attribute-Based Hierarchical Access Control With Extendable Policy

Attribute-based encryption scheme is a promising mechanism to realize one-to-many fine-grained access control which strengthens the security in cloud computing. However, massive amounts of data and various data sharing requirements bring great challenges to the complex but isolated and fixed access structures in most of the existing attribute-based encryption schemes. In this paper, we propose an attribute-based hierarchical encryption scheme with extendable policy, called Extendable Hierarchical Ciphertext-Policy Attribute-Based Encryption (EH-CP-ABE), to improve the data sharing efficiency and security simultaneously. The scheme realizes the function of hierarchical encryption, in which, data with hierarchical access control relationships could be encrypted together flexibly to improve the efficiency. The scheme also achieves external and internal extension of the access structure to further encrypt newly added hierarchical data without updating the original ciphertexts or with only a minor update depending on the data sharing requirements, which simplifies the encryption process and greatly reduces the computation overhead. We formally prove the security of the scheme is IND-CCA secure in the random oracle model based on bilinear Diffie-Hellman assumption, and we also implement our scheme to demonstrate its efficiency and practicality.

Towards Secure and Privacy-Preserving Data Sharing for COVID-19 Medical Records: A Blockchain-Empowered Approach

COVID-19 is currently a major global public health challenge. In the battle against the outbreak of COVID-19, how to manage and share the COVID-19 Electric Medical Records (CEMRs) safely and effectively in the world, prevent malicious users from tampering with CEMRs, and protect the privacy of patients are very worthy of attention. In particular, the semi-trusted medical cloud platform has become the primary means of hospital medical data management and information services. Security and privacy issues in the medical cloud platform are more prominent and should be addressed with priority. To address these issues, on the basis of ciphertext policy attribute-based encryption, we propose a blockchain-empowered security and privacy protection scheme with traceable and direct revocation for COVID-19 medical records. In this scheme, we perform the blockchain for uniform identity authentication and all public keys, revocation lists, etc are stored on a blockchain. The system manager server is responsible for generating the system parameters and publishes the private keys for the COVID-19 medical practitioners and users. The cloud service provider (CSP) stores the CEMRs and generates the intermediate decryption parameters using policy matching. The user can calculate the decryption key if the user has private keys and intermediate decrypt parameters. Only when attributes are satisfied access policy and the user's identity is out of the revocation list, the user can get the intermediate parameters by CSP. The malicious users may track according to the tracking list and can be directly revoked. The security analysis demonstrates that the proposed scheme is indicated to be safe under the Decision Bilinear Diffie-Hellman (DBDH) assumption and can resist many attacks. The simulation experiment demonstrates that the communication and storage overhead is less than other schemes in the public-private key generation, CEMRs encryption, and decryption stages. Besides, we also verify that the proposed scheme works well in the blockchain in terms of both throughput and delay.

SEPS: Efficient public-key based secure search over outsourced data

With the recent advancement of cloud storage services, many cloud customers (data owners) are migrating their data from local storage to cloud data storage to reduce maintenance cost. Once data is outsourced, the data owners loose control over their data, evolving various security and privacy issues. To resolve this issue, data encryption is an effective solution. Meanwhile, to increase the utilization of the encrypted outsourced data, searchable encryption would be an efficient tool capable enough to search over encrypted data. In this work, we propose a novel public-key based searchable encryption scheme (SEPS) using an inverted index data structure. We show that SEPS achieves better performance than previous efforts (both theoretically and experimentally). We prove the security of the proposed scheme using Bilinear Diffie–Hellman assumption. SEPS withstands keyword guessing attack and achieves trapdoor privacy. On the top, the index generation process of the proposed scheme is secure against chosen keyword attack. AVISPA tool is also used for the formal security verification of SEPS and found to be attack resistant.

PvCT: A Publicly Verifiable Contact Tracing Algorithm in Cloud Computing

Contact tracing is a critical tool in containing epidemics such as COVID-19. Researchers have carried out a lot of work on contact tracing. However, almost all of the existing works assume that their clients and authorities have large storage space and powerful computation capability and clients can implement contact tracing on their own mobile devices such as mobile phones, tablet computers, and wearable computers. With the widespread outbreaks of the epidemics, these approaches are of less robustness to a larger scale of datasets when it comes to resource-constrained clients. To address this limitation, we propose a publicly verifiable contact tracing algorithm in cloud computing (PvCT), which utilizes cloud services to provide storage and computation capability in contact tracing. To guarantee the integrity and accuracy of contact tracing results, PvCT applies a novel set accumulator-based authentication data structure whose computation is outsourced, and the client can check whether returned results are valid. Furthermore, we provide rigorous security proof of our algorithm based on the q -Strong Bilinear Diffie–Hellman assumption. Detailed experimental evaluation is also conducted on three real-world datasets. The results show that our algorithm is feasible within milliseconds of client CPU time and can significantly reduce the storage overhead from the size of datasets to a constant 128 bytes.

A new construction of leakage-resilient CCA secure IBE scheme

Leakage of private information has become a threat to the security of cryptography systems. It has become a common security requirement that a cryptography scheme should withstand various leakage attacks. The non-interactive zero-knowledge (NIZK) argument system, one-time lossy filter (OT-LF) and one-time signature were widely used to create the generic constructions of leakage-resilient identity-based encryption (IBE) scheme with chosen-ciphertext attack (CCA) security. However, the computational efficiency of the corresponding generic construction is low because the underlying cryptographic tool is low. Thus, to solve the above problem, a new cryptographic primitive, called identity-based hash proof system with two encapsulated-key (T-IB-HPS), is proposed. The new generic constructions of leakage resilient IBE scheme with CCA security is created from the T-IB-HPS and message authentication code (MAC), and the security of the above proposed scheme is proved from the security of the underlying cryptographic tool. To further show the practicability, an instantiation of T-IB-HPS is constructed, and the formal security proof of the above instantiation is shown based on the decisional bilinear Diffie-Hellman (DBDH) assumption. Compared with the previous generic constructions of leakage resilient IBE scheme with CCA security, since the underlying cryptographic tools with low computational efficiency are not used, our generic construction has high computational efficiency.

Reliable file transfer protocol with producer anonymity for Named Data Networking

Named Data Networking (NDN) is a transmutational construction for the Future Internet equipped toward approaching the Internet’s numerous problems, including content security, content caching, and administration complexity. Security policy in the NDN is based on the digital signatures appended to all the transmitted packets in the NDN. However, a digital signature leaks the identity of the actual producer. To hide the producer’s identity, this paper designs a secure data transmission protocol that ensures the producer’s anonymity in the NDN. The proposed protocol is based on the concepts of Shao et al.’s proxy re-signature and Fan et al.’s methods. Besides, it is formally secured under the intractability of the Decisional Bilinear Diffie–Hellman assumption. Feasibility analysis demonstrates that the proposed protocol not only inherits the benefits of data confidentiality, supporting unknown potential receivers, and lower storage cost, but also supports the producer’s anonymity with minimal overheads.