Diffie-Hellman Assumption Research Articles

Hidden Issuer Anonymous Credential

Identity Management Systems (IMS) allow users to prove characteristics about themselves to multiple service providers. IMS evolved from impractical, site-by-site authentication, to versatile, privacyenhancing Self Sovereign Identity (SSI) Frameworks. SSI frameworks often use Anonymous Credential schemes to provide user privacy, and more precisely unlinkability between uses of these credentials. However, these schemes imply the disclosure of the identity of the Issuer of a given credential to any service provider. This can lead to information leaks. We deal with this problem by introducing a new Anonymous Credential scheme that allows a user to hide the Issuer of a credential, while being able to convince the service providers that they can trust the credential, in the absence of a trusted setup. We prove this new scheme secure under the Computational Diffie Hellman assumption, and Decisional Diffie Hellman assumption, in the Random Oracle Model. We show that this scheme is efficient enough to be used with laptops, and to be integrated into SSI frameworks or any other IMS.

Certificateless public auditing scheme with designated verifier and privacy-preserving property in cloud storage

In recent years, cloud storage has become an attractive service for data owners to store their personal data. Since they lose physical control of their data, it is necessary to regularly audit its integrity. The public auditing technique is very popular because it is suitable to outsource the auditing task to any third-party auditor, who has professional knowledge on auditing. However in many practical scenarios, the data owner may expect some designated verifier (instead of any) to audit its data. Thus, the public auditing scheme with designated verifier was proposed. In order to further reduce the cost of managing certificates, and to avoid the dependence on public key infrastructure , identity-based auditing scheme with designated verifier was recently proposed. Nevertheless, the proposed identity-based auditing scheme still suffers from the key escrow attack the risk of privacy leakage . In this paper, for the first time, we propose a certificateless public auditing protocol with designated verifier privacy-preserving property. More concretely, it can not only protect the privacy of the stored data against the designated verifier, but also resolve key escrow problem existed in identity-based technique. Its security is based on the Computational Diffie–Hellman and Weil Diffie–Hellman assumptions. Finally, the performance analysis experimental results of the proposed protocol show that our auditing scheme is efficient feasible to applications in real life.

Some analysis on conjugacy search problem for Diffie-Hellman protocol

The field in nonabelian group-based cryptosystem have gain attention of the researchers as it expected to offers higher security when confronted with quantum computational due to more complex algebraic structures. Hence, this paper intents to give an overview on Diffie-Hellman protocol considering the mathematically hard problem such as the conjugacy search problem in a group G. In this paper we provide examples for G of non abelian group particularly the group of SL(2,3).

HSC-MET: Heterogeneous signcryption scheme supporting multi-ciphertext equality test for Internet of Drones.

Internet of Drones (IoD) is considered as a network and management architecture, which can enable unmanned aerial vehicles (UAVs) to collect data in controlled areas and conduct access control for UAVs. However, the current cloud-assisted IoD scheme cannot efficiently achieve secure communication between heterogeneous cryptosystems, and does not support multi-ciphertext equality tests. To improve the security and performance of traditional schemes, we propose a heterogeneous signcryption scheme (HSC-MET) that supports multi-ciphertext equality test. In this paper, we use a multi-ciphertext equality test technique to achieve multi-user simultaneous retrieval of multiple ciphertexts safely and efficiently. In addition, we adopt heterogeneous signcryption technology to realize secure data communication from public key infrastructure (PKI) to certificateless cryptography (CLC). At the same time, the proposed scheme based on the computation without bilinear pairing, which greatly reduces the computational cost. According to the security and performance analysis, under the random oracle model (ROM), the confidentiality, unforgeability and number security of HSC-MET are proved based on the computational Diffie-Hellman (CDH) problem.

Signed (Group) Diffie–Hellman Key Exchange with Tight Security

We propose the first tight security proof for the ordinary two-message signed Diffie–Hellman key exchange protocol in the random oracle model. Our proof is based on the strong computational Diffie–Hellman assumption and the multiuser security of a digital signature scheme. With our security proof, the signed DH protocol can be deployed with optimal parameters, independent of the number of users or sessions, without the need to compensate any security loss. We abstract our approach with a new notion called verifiable key exchange. In contrast to a known tight three-message variant of the signed Diffie–Hellman protocol (Gjøsteen and Jager, in: Shacham, Boldyreva (eds) CRYPTO 2018, Part II. LNCS, Springer, Heidelberg, 2018), we do not require any modification to the original protocol, and our tightness result is proven in the “Single-Bit-Guess” model which we know can be tightly composed with symmetric cryptographic primitives to establish a secure channel. Finally, we extend our approach to the group setting and construct the first tightly secure group authenticated key exchange protocol.

A New Certificateless Signcryption Scheme for Securing Internet of Vehicles in the 5G Era

The application of digital signature technology to the Internet of vehicles (IoV) is affected by its network and communication environment. In the 5G era, the influx of a large number of intelligent devices into the mobile Internet requires a low transmission delay and power consumption as well as high-security requirements. To the best of our knowledge, a well-designed solution in which signcryption technology is used has not been proposed in the IoV research area. Motivated by the fact, a certificateless signcryption scheme based on the elliptic curve digital signature algorithm, in which pseudonym and timestamp mechanism are also considered, has been designed in this paper. We prove that the scheme proposed by us can be reduced to solving the difficulty of the computational Diffie–Hellman problem with a standard model, showing that the scheme meets requirements on both security and efficiency, which provides a comparative analysis with the state-of-the-art schemes in terms of security analysis, computational cost, and communication cost, demonstrating that the scheme proposed by us is suitable to be deployed in the IoV environment, which is of the characteristics of high-speed vehicle movement.

Breaking the Decisional Diffie–Hellman Problem for Class Group Actions Using Genus Theory: Extended Version

Breaking the Decisional Diffie–Hellman Problem for Class Group Actions Using Genus Theory: Extended Version

RMA-CPABE : A multi-authority CPABE scheme with reduced ciphertext size for IoT devices

Internet of Things (IoT) generates a massive amount of data, which can be prone to huge data and privacy leaks unless given a proper access control. Ciphertext-policy attribute-based encryption (CP-ABE) is a well-known cryptographic mechanism that provides confidentiality and fine-grained access to stored data. In CP-ABE, a single trusted authority primarily handles attribute management and its revocation. However, in an environment like IoT, due to its heterogeneous nature, the attributes from multiple domains are evidently inherited by IoT devices and hence develop a need for a multi-authority scheme. Therefore, this paper proposes a novel multi-authority CP-ABE scheme with reduced-size ciphertext (RMA-CPABE) to provide secure access in fog-enabled IoT applications with attributes from multiple domains. This scheme considers the resource-constrained nature of IoT devices and reduces the ciphertext size in the sense that the ciphertext size does not increase linearly with the number of attributes; instead, it increases linearly with the number of multi-domain attribute authorities involved in the policy building. RMA-CPABE supports highly required functionalities like attribute update and outsourced decryption to reduce the computation load on the end devices. Further, the proposed scheme is the first to eliminate the most expensive ciphertext update operation during attribute revocation and addition, which is the biggest drawback of most of the existing schemes. The end-user in RMA-CPABE requires holding only a constant size key to access the ciphertexts securely. The security analysis proves that the proposed scheme is secure against Chosen-Ciphertext Attack (CCA) under multiple augmented Multi-Sequence of Exponents Decisional Diffie Hellman (maMSE-DDH) assumptions. The performance analysis shows that RMA-CPABE is suitable for IoT applications.

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.

Dynamic permission access control model based on privacy protection

Access control technology is one of the key technologies to ensure safe resource sharing. Identity authentication and authority distribution are two key technologies for access control technology to restrict unauthorized users from accessing resources, and only authorised legal users can access resources. However, user privacy protection and frequent permission changes are two thorny issues that need to be solved urgently by access control technology. In this paper, a dynamic access control model based on privacy protection is proposed to deal with these problems. Compared with existing access control technologies, the main advantages of this paper are as follows: (1) Encrypt and hide the attributes of entities, and use attribute-based identity authentication technology for identity authentication, which not only achieves the purpose of traditional identity authentication, but also ensures the attributes and privacy of entities are not leaked; (2) Binding resource access permissions with entity attributes, dynamically assigning and adjusting resource access control permissions through changes in entity attributes, making resource access control more fine-grained and more flexible. Security proof and performance analysis show that the proposed protocol is secure under the hardness assumption of the discrete logarithm problem and the decision bilinear Diffie–Hellman problem. Compared with the cited references, this model has the advantages of low computational complexity, short computational time, and low communication overhead.

Classically verifiable quantum advantage from a computational Bell test

Existing experimental demonstrations of quantum computational advantage have had the limitation that verifying the correctness of the quantum device requires exponentially costly classical computations. Here we propose and analyse an interactive protocol for demonstrating quantum computational advantage, which is efficiently classically verifiable. Our protocol relies on a class of cryptographic tools called trapdoor claw-free functions. Although this type of function has been applied to quantum advantage protocols before, our protocol employs a surprising connection to Bell’s inequality to avoid the need for a demanding cryptographic property called the adaptive hardcore bit, while maintaining essentially no increase in the quantum circuit complexity and no extra assumptions. Leveraging the relaxed cryptographic requirements of the protocol, we present two trapdoor claw-free function constructions, based on Rabin’s function and the Diffie–Hellman problem, which have not been used in this context before. We also present two independent innovations that improve the efficiency of our implementation and can be applied to other quantum cryptographic protocols. First, we give a scheme to discard so-called garbage bits, removing the need for reversibility in the quantum circuits. Second, we show a natural way of performing postselection that reduces the fidelity needed to demonstrate quantum advantage. Combining these results, we describe a blueprint for implementing our protocol on Rydberg atom-based quantum devices, using hardware-native operations that have already been demonstrated experimentally.

Provably Secure Linearly Homomorphic Aggregate Signature Scheme for Electronic Healthcare System

In recent years, deploying Internet of Things (IoT) in electronic healthcare systems (EHS) has made great progress in healthcare detection. It is extremely important to reduce the cost of communication and ensure the authenticity and integrity of data. A linearly homomorphic signature scheme can solve the above problems. However, when the scale of EHS is too large, the transmission, storage and verification of signatures need a high cost. An aggregate signature can combine many signatures generated by many different users into a short one. Therefore, only one aggregate signature needs to be processed during verification, transmission and storage. Combining the advantages of aggregate signature and linearly homomorphic signature, this paper proposes an aggregate signature scheme based on a linearly homomorphic signature for EHS, which has both linear homomorphism and aggregation, and realizes double data compression. Moreover, our scheme can resist a potential real attack, named a coalition attack. The security of this scheme is rigorously demonstrated based on the computational Diffie–Hellman assumption in the random oracle model.

ID-based sanitizable signature data integrity auditing scheme with privacy-preserving

More and more companies, institutions and organizations are choosing to put vast amounts of data on the cloud. However, applications such as multimedia office, e-government and e-health systems need to withhold some data in order to hide highly confidential information when uploading to the cloud. A new data integrity auditing scheme is proposed to protect the privacy information and share the data. The idea of sanitizable signature is used to sanitize the private data to protect the privacy and generate effective signatures to verify the integrity of the data. At the same time, the identity-based encryption auditing mechanism simplifies the complex certificate management and improves the audit efficiency. The stability of the scheme is verified by calculating the Computational Diffie-Hellman Problem (CDHP) and Discrete Logarithm Problem (DLP) in the stochastic prediction model. The performance of the proposed scheme is evaluated by simulation experiments, which proves that the proposed scheme is safe and effective.

Multicopy and Multiserver Provable Data Possession for Cloud-Based IoT

Provable data possession (PDP) is widely considered to be an efficient method in verifying the integrity of remote data. While earlier PDP schemes are generally designed to check the integrity of data copies on a single cloud server (CS), there have been attempts to design multicopy and multiserver PDP (MCMS-PDP) schemes in recent years. However, it is known that MCMS-PDP schemes may be vulnerable to copy-summation attacks or do not support dynamic operations. The former enables a (dishonest) CS to only store a summation of copies for successful verification, while the latter does not allow the data owner to update the stored data. In this article, we propose a new MCMS-PDP scheme based on homomorphic verifiable tags. Specifically, our proposed scheme is designed to check the integrity of all copies in one challenge–response and resist copy-summation attacks. The scheme also supports public verification and block-level dynamic operations, such as modification, insertion, and deletion using the divide-and-conquer table. We then prove the security of our scheme, assuming the intractability of the computational Diffie–Hellman problem, in the random oracle model. We also evaluate the performance of the scheme to demonstrate its efficiency.

Torsion point attacks on ‘SIDH‐like’ cryptosystems

AbstractIsogeny‐based cryptography is a promising approach for post‐quantum cryptography. The best‐known protocol following that approach is the supersingular isogeny Diffie–Hellman protocol (SIDH); this protocol was turned into the CCA‐secure key encapsulation mechanism SIKE, which was submitted to and remains in the third round of NIST's post‐quantum standardisation process as an ‘alternate’ candidate. Isogeny‐based cryptography generally relies on the conjectured hardness of computing an isogeny between two isogenous elliptic curves, and most cryptanalytic work referenced on SIKE's webpage exclusively focusses on that problem. Interestingly, the hardness of this problem is sufficient for neither SIDH nor SIKE. In particular, these protocols reveal additional information on the secret isogeny, in the form of images of specific torsion points through the isogeny. This paper surveys existing cryptanalysis approaches exploiting this often called ‘torsion point information’, summarises their current impact on SIKE and related algorithms, and suggests some research directions that might lead to further impact.

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.

An Efficient Certificateless Ring Signcryption Scheme With Conditional Privacy-Preserving in VANETs

As an ever-increasing ingredient of intelligent transportation systems, vehicular ad hoc networks (VANETs) can be leveraged to improve road safety and driving convenience. However, the extreme mobility and volatility of VANETs can arouse serious concerns about vehicle identity privacy leakages as well as the authenticity and confidentiality of safety messages in vehicular communication. To cope with these issues, we propose a certificateless ring signcryption scheme with conditional privacy-preserving based on elliptic curve cryptography, which can provide secure vehicular communication with low transmission latency and communication overhead. Besides, by integrating a tracking mark into the safety message, we design a tracking algorithm that enables the trusted party to distinguish malicious vehicles from the ring member list. It realizes conditional privacy while avoiding the huge cost of vehicular storage resources. Through security analysis, this scheme is proven to be secure under the Elliptic curve discrete logarithm and Elliptic curve computational Diffie–Hellman assumptions in the random oracle model. Finally, we implement the performance evaluations in terms of the computational overhead, the communication bandwidth and the packet loss rate. By utilizing the MIRACL cryptography library and the Veins simulation framework, the results illustrate that the proposed scheme can support an efficient and highly reliable communication protocol for safety-related applications in VANETs environment.

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.

Application of Digital Twin Combined with Artificial Intelligence and 5G Technology in the Art Design of Digital Museums

More and more museums are being established or restored as people’s cultural levels grow. A digital twin is a computerized representation of the physical object or phenomenon, which acts as its real-time digital equivalent. Artificial intelligence (AI) is becoming increasingly widespread, and museums and art shows will need to change their old working and thinking processes to fully fulfill their potential. In an increasingly digital world, combining AI technologies and wearable devices into digital museums could assist in boosting involvement. It is necessary to investigate AI’s strategic function and application in affecting tourist experiences at art galleries and museums, as well as its potential to improve education. Also, digital twin (DT) paves the way to alleviate difficulties or might improve access to digital museums via digital experiences. The historical report recommends that digital museum items be represented in a way that poses the fewest threats to its legitimacy. Owing to its uniqueness and vulnerability to substantial environmental dangers, the safeguarding of art and cultural heritage in digital museums is a serious issue. There are many approaches for assessing the state of artistic heritage and protecting it from extreme acts. The current study offers a framework for digitized museum art design based on the utilization of digital twin (DT), artificial intelligence (AI), and fifth-generation (5G) technologies. Further to enhance the security of the system, we employ the improved blowfish encryption algorithm (IBEA). Also, the authentication is done using the Diffie-Hellman protocol. The proposed system is simulated using MATLAB, and its performance is analyzed and compared with conventional systems. From the result obtained, it was revealed that the suggested methodology express high range of security level (95%) than the existing mechanisms. This study is very important in two directions: (1) it presents an analytical structure for having to adapt digital information to complicated systems in museums and (2) it explains the artistic obstacles for heritage properties, such as accessibility, execution time, security level, and the efficiency of 3-dimensional designs.

Certificateless Elliptic Curve Aggregate Signcryption Scheme

Driven by new situation of “Internet +,” Internet has achieved the integrated development with all walks of life. Among them, the fifth generation is a key technology to promote the deep integration of Internet-of-Things equipment, cloud computing, blockchain and other trades. Hence, it is necessary for IoTs to consider the cost and efficiency of authentication and confidentiality of the communication. For effectively solving the above problems, we devise certificateless elliptic curve aggregate signcryption (CL-ECASC) scheme for IoTs that can improve the authentication efficiency, realize data confidentiality, and avoid the problems of complex certificate management and key escrow. Under the hardness of discrete logarithm and computational DiffieHellman problems on elliptic curve, CL-ECASC is proved to has the IND-CCA2 security (indistinguishability under the adaptive chosen-ciphertext attacks) and UF-CMA security (existentially unforgeable under the adaptive chosen-message attacks). CL-ECASC has relatively faster computation efficiency and lower communication cost, and so it is suitable for secure transmission of the information in the previously mentioned environments.