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The article "Demystifying Quantum" discusses two key quantum developments in cybersecurity: post-quantum cryptography (PQC) and quantum key distribution (QKD). PQC addresses the threat posed by quantum computing to classical algorithms like RSA, while QKD ensures secure key exchange. The article highlights the differences between PQC and QKD in mitigating the risk of quantum computers breaking RSA encryption. It also discusses the challenges and implications of implementing quantum-based solutions in cryptographic systems. [Extracted from the article]

A nanocomposite with a unique satellite dish-like structure, termed arsenic (III) oxide iodide (AsO2I)/polypyrrole (Ppy) intercalated with iodide ions (AsO2I/Ppy-I), has been meticulously developed via a two-step process. It features natural satellite dish-like nanostructures, potentially serving as nanoresonators for efficient single photon absorption. With a bandgap of 2.8 eV, the AsO2I/Ppy-I nanocomposite efficiently absorbs photons in the UV and visible light regions, making it suitable for single photon detection. Impressive performance is seen in photocurrent sensitivity measurements, recording values of 0.017 mA.cm−2 under white light and 0.009 mA.cm−2 under monochromatic light at 340 nm. Additionally, it exhibits high responsivity and detectivity, with peak values at wavelengths of 340 nm and 440 nm associated with the diameter of the Satellite dish nanostructure. Cost-effectiveness and simple synthesis methods make it attractive for industrial applications, while its unique structural characteristics and enhanced optical properties position it as a valuable asset in optoelectronic technologies. It holds promise as a leading material in advanced quantum technology, marking a significant leap forward in optoelectronic technologies, with potential applications in quantum cryptography, communication, and computing. [ABSTRACT FROM AUTHOR]

Optical communications providing huge capacity and low latency remain vulnerable to a range of attacks. In consequence, encryption at the optical layer is needed to ensure secure data transmission. In our previous work, we proposed LightPath SECurity (LPSec), a secure cryptographic solution for optical transmission that leverages stream ciphers and Diffie–Hellman (DH) key exchange for high-speed optical encryption. Still, LPSec faces limitations related to key generation and key distribution. To address these limitations, in this paper, we rely on Quantum Random Number Generators (QRNG) and Quantum Key Distribution (QKD) networks. Specifically, we focus on three meaningful scenarios: In Scenario A, the two optical transponders (Tp) involved in the optical transmission are within the security perimeter of the QKD network. In Scenario B, only one Tp is within the QKD network, so keys are retrieved from a QRNG and distributed using LPSec. Finally, Scenario C extends Scenario B by employing Post-Quantum Cryptography (PQC) by implementing a Key Encapsulation Mechanism (KEM) to secure key exchanges. The scenarios are analyzed based on their security, efficiency, and applicability, demonstrating the potential of quantum-enhanced LPSec to provide secure, low-latency encryption for current optical communications. The experimental assessment, conducted on the Madrid Quantum Infrastructure, validates the feasibility of the proposed solutions. [ABSTRACT FROM AUTHOR]

Quantum secret sharing (QSS) is a fundamental primitive in quantum cryptography. The existing QSS protocols are either (n,n)-threshold or (t,n)-threshold access structure, where n denotes the number of players and t denotes the threshold number of players. Here, we introduce a novel verifiable QSS scheme that executes a restricted hyperstar access structure by using entangled states. Our method involves encoding selected quantum states and their corresponding measurements to yield outcomes of either + 1 or − 1. Furthermore, we give the validation of the scheme through the system of equations derived from the measurements, which then guarantees the honesty of the participants. At last, we also analyze the security of our scheme in two primary quantum attacks, such as external attacks and internal attacks. [ABSTRACT FROM AUTHOR]

As a result of the development of digital and internet technologies, digital content theft has become a major problem for the multimedia industry. Piracy is controlled by digital rights management (DRM) system. Multimedia on mobile devices is a novel idea for businesses where security is crucial. Numerous anonymous authentication schemes for mobile-DRM (M-DRM) systems have been developed during the past decade using the assumptions of factorization and discrete logarithms, which are proved insecure in the presence of scalable quantum computers by Shor's algorithm. Therefore, a quantum secure communication mechanism must be developed for M-DRM systems. To create a quantum-safe environment, this paper designs a lattice-based three-factor authentication session establishment technique for content key sharing in the DRM system, which provides forward secrecy and user anonymity and resists off-line password guessing, replay, impersonation, insider and signal leakage attacks. The random oracle model (ROM) is adopted to design the scheme's proof. Further, a comparison of existing schemes with the proposed scheme in terms of execution and communication costs is provided to demonstrate the efficiency of designed protocol. [ABSTRACT FROM AUTHOR]

Quantum secret sharing holds an important place in quantum cryptography. In this paper, a threshold changeable dynamic quantum secret sharing scheme with cheating identification is firstly proposed based on the Chinese Remainder Theorem. On the premise of not altering the shared secret and the private shares of the original participants, our scheme realizes the dynamic updating of participants and for the first time achieves the changeable threshold in the quantum environment, which greatly improves the flexibility and practicality of the scheme. In addition, we generalize the entanglement swapping equations of Bell states in 2-dimension to d-dimension. During the reconstruction phase, our scheme can timely detect and identify the cheating behaviors based on the randomized components and the entanglement swapping equations of d-dimensional Bell states. Meanwhile, the randomized components ensure privacy protection for shares and avoid the interference of invalid shares when recovering the secret. Security analysis shows that our scheme is resistant to not only a series of typical external attacks but also forgery, collusion, and dishonest revoked participant attacks. Compared with the existing schemes, our scheme is not only more secure and efficient but also has lower computational consumption. [ABSTRACT FROM AUTHOR]

A few years ago Hong et al. (Quantum Inf Process 16:236, 2017) proposed a quantum identity authentication protocol using single photons and executable on currently available quantum hardware. Zawadzki later published two attacks on this protocol, and suggested a mitigation in the same work. In this comment we point out an additional vulnerability that causes the prover Alice to leak a percentage of her secret key at every authentication attempt. The latter is due to a problematic policy in the generation and management of decoy states. We conclude by showing a simple mitigation that addresses the issue. [ABSTRACT FROM AUTHOR]

This paper proposes a verifiable dynamic multi-dimensional quantum secret sharing scheme utilizing a generalized Hadamard gate. The dealer simultaneously distributes quantum and classical information to participants in a single distribution using a generalized Hadamard gate and a quantum SUM gate. To detect the malicious behavior of participants, the dealer prepares a sequence of checking particles. The participants retrieve the secret quantum state and classical information utilizing a generalized Hadamard gate and single-particle measurement. Additionally, the authenticity of secrets is ensured using a public hash function. While adding or removing participants, the dealer does not require assistance from other participants. The proposed protocol effectively thwarts eavesdroppers and participants from performing several types of attacks, including collusion, forgery, denial, and revoked dishonest participant attacks. The proposed protocol yields greater reliability, simplicity, versatility, and practicality. [ABSTRACT FROM AUTHOR]

In the field of quantum cryptography, quantum secret sharing (QSS) holds substantial importance, with identity authentication emerging as a key strategy for safeguarding information. It efficiently certifies the identification of both persons involved in the conversation, which contributes to increased security measures. Our proposed, (m , n) threshold quantum secret sharing (QSS) scheme introduces a unique approach to mutual identity authentication, utilizing mutually unbiased bases. Alice employs a symmetric bivariate polynomial to distribute the secret share among all participants in this algorithm. For secret reconstruction, a trusted participant, Bob 1 , shares a GHZ state with a qualified group of m participants, including himself. Each participant applies QFT and a unitary transformation (related to their part of the shared secret) on their particle. During the secret recovery phase, the scheme ensures that secrets exclusively held by participants remain undisclosed and are not transmitted, reinforcing the security of the communication process. As a result, external eavesdroppers are left empty-handed in their attempt to access information about secrets during this phase. Our protocol surpasses in terms of security, effectiveness, and practicality, proving its resilience against intercept–resend attacks, collision attacks, collective attacks, entangle-measure attacks, and forgery attacks according to a comprehensive security analysis. [ABSTRACT FROM AUTHOR]

The security of digital information is one of the most unavoidable issue in current digital world. The existing world facing number of digital information breaches due to weak utilization of confidentiality preserving techniques. In this article, we have designed a new mechanism for the security of secret digital information for instance digital images. The proposed image encryption scheme is based on quantum harmonic oscillator and Schrodinger paradox. Moreover, suggested technique is further authenticated by utilizing security performance analysis and compared the obtained results with existing benchmarks schemes. [ABSTRACT FROM AUTHOR]

Quantum digital signature, as an extension of classical digital signature, has become an important research content in quantum cryptography. Quantum blind signature combines the advantages of classical blind signature and quantum signature, which can ensure the unconditional security of the scheme based on the realization of the blinded signature of the message, and can be effectively applied in many real-world scenarios. This paper uses the four-particle χ state as a communication channel, combined with quantum teleportation technology to propose a new quantum multi-party blind signature protocol, which has the following characteristics: First, the Toeplitz hash function based on the linear shift register is introduced to blind the message, and the length of the blinded message can be adjusted according to the actual demand to increase the flexibility of the scheme; Second, through multi-party participation, the blind signature of multi-bit messages can be realized, and the signature efficiency can be improved. Compared with other quantum blind signatures, the signature efficiency has been greatly improved; Finally, using the four-particle χ state as a quantum channel can make the scheme use fewer resources to transmit data and increases the security of the scheme. Through security analysis, it can be seen that the scheme has blindness, nonrepudiation and unforgeability. [ABSTRACT FROM AUTHOR]

The no-go theorem regarding unconditionally secure Quantum Bit Commitment protocols is a relevant result in quantum cryptography. Such result has been used to prove the impossibility of unconditional security for other protocols such as Quantum Oblivious Transfer or One-Sided Two Party Computation. In this paper, we formally define two non-deterministic versions of Quantum Private Queries, a protocol addressing the Symmetric-Private Information Retrieval problem. We show that the strongest variant of such scheme is formally equivalent to Quantum Bit Commitment, Quantum Oblivious Transfer and One-Sided Two-Party Computation protocols. This equivalence serves as conclusive evidence of the impracticality of achieving unconditionally secure Strong Probabilistic Quantum Private Queries. [ABSTRACT FROM AUTHOR]

The threat of quantum computing has spurred research into post-quantum cryptography. SQIsign, a candidate submitted to the standardization process of the National Institute of Standards and Technology, is emerging as a promising isogeny-based signature scheme. This work aimed to enhance SQIsign's practical deployment by optimizing its low-level arithmetic operations. Through hierarchical decomposition and performance profiling, we identified the ideal-to-isogeny translation, primarily involving elliptic curve operations, as the main bottleneck. We developed efficient 32-bit finite field arithmetic for elliptic curves, such as basic operations, like addition with carry, subtraction with borrow, and conditional move. We then implemented arithmetic operations in the Montgomery domain, and extended these to quadratic field extensions. Our implementation offers improved compatibility with 32-bit architectures and enables more fine-grained SIMD acceleration. Performance evaluations demonstrated the practicality in low-level operations. Our work has potential in easing the development of SQIsign in practice, making SQIsign more efficient and practical for real-world post-quantum cryptographic applications. [ABSTRACT FROM AUTHOR]

The wireless body area network (WBAN) has emerged as a promising networking paradigm thanks to embedded systems, integrated circuit technologies, and wireless communications advancements. WBAN has the ability to send real-time biomedical data to remote medical personnel for clinical diagnostics through intelligent medical sensors in or around the patient's body. Moreover, WBANs have played an increasingly important role in modern medical systems over the past decade as part of the Internet of Things (IoT). In addition to their conveniences, WBANs present us with the data confidentiality challenge and protecting patient's privacy. The system requires a robust security mechanism to protect against threats because of the massive production of delay-sensitive data. This article presents a quantum key distribution (QKD) protocol-based authentication scheme for secure communication within WBAN infrastructure to prevent attacks and provide services free of security risks. To the best of our knowledge, we proposed a privacy preserving quantum authentication scheme for secure data sharing in WBANs to enhance security by encrypting medical data and safeguarding patients identities. Simulations conducted using Mathematica evaluate the proposed quantum authentication protocol both theoretically and practically, showing strong encryption performance against recent schemes. Results include computational cost of 6.832 ms, communication costs of 588 bits, and energy consumption of 432.98 μ J indicating the proposed quantum authentication protocol model exhibits superior reliability, feasibility, and efficiency in safeguarding WBAN data during transmission and storage. [ABSTRACT FROM AUTHOR]

Smart cities, fueled by the Internet of Things (IoT), promise urban efficiency and convenience. However, it has also exposed vulnerabilities in the security and privacy of sensitive data transmitted and stored within these interconnected networks. The increasing frequency of cyberattacks and data breaches underscores the pressing need for innovative solutions to enhance the security of smart city IoT systems. This paper introduces a novel approach to bolstering IoT security in smart cities by adapting quantum cryptography principles. Leveraging quantum steganography, we conceal sensitive data within quantum streams. The proposed model provides a comprehensive solution that ensures the confidentiality, integrity, and authenticity of data within smart city IoT ecosystems. By combining quantum steganography, reversible decoding, customized encryption, privacy amplification, and cryptographic verification, this protocol fosters trust among stakeholders and supports the secure evolution of urban environments. This research offers a blueprint for securing IoT in smart cities, fostering trust, and enabling the safe evolution of urban environments. [ABSTRACT FROM AUTHOR]

With the advent of internet-enabled and hybrid technologies, information is becoming increasingly accessible to the general public. Smartphones and other gadgets are used extensively by people to share and promote ideas, in a variety of ways. Human interaction and communication has become more reliable and effective through advanced computing technologies. Quantum computing is an emerging paradigm that will change the lives of individuals and the operations of organizations. Quantum computers solve problems at high speed by operating in a superposition state in which the state can be either zero or one at the same instant. Quantum sensors can be used efficiently in technological research to make accurate measurements and collect data that provide new insights into the behavior of nanomaterials. The use of quantum computing could also speed up the manufacturing process of devices with remarkable properties such as superconductivity, high strength or improved signal performance. Quantum computing has the ability to dramatically speed up the development process of various organizations and increase their efficiency and effectiveness. The security and reliability of data and communication is improved by quantum computing techniques such as key generation and entanglement dispersion. Companies use cryptographic algorithms to protect their data. However, with the advent of quantum computing, cryptographic methods that rely on numerical aspects are no longer sufficient to protect data. Quantum computing is an emerging field that is being applied to various problems that previously could not be solved using conventional methods. Quantum computing plays an important role in the field of information processing, where information is precisely analyzed. Various quantum technologies and algorithms are used to secure company data. This paper provides a systematic review of the literature on the principles of quantum computing. The SLR focuses on achieving four aims "identifying a variety of quantum IoT devices, analyzing their importance in different industries, highlighting the challenges of quantum technology, and presenting various techniques used by researchers to overcome different problems". Quantum cryptography is identified as a key strategy for improving the security of IoT systems and ensuring the security and consistency of information. [ABSTRACT FROM AUTHOR]

In this study, we report a transmitter system for free‐space quantum key distribution (QKD) using the BB84 protocol, which does not require an internal alignment process, by using a wavelength‐division multiplexing (WDM) filter and polarization‐encoding module. With a custom‐made WDM filter, the signals required for QKD can be integrated by simply connecting fibers, thus avoiding the laborious internal alignment required for free‐space QKD systems using conventional bulk‐optic setups. The WDM filter is designed to multiplex the single‐mode signals from 785‐nm quantum and 1550‐nm synchronization channels for spatial‐mode matching while maintaining the polarization relations. The measured insertion loss and isolation are 1.8 dB and 32.6 dB for 785 nm and 0.7 dB and 28.3 dB for 1550 nm, respectively. We also evaluate the QKD performance of the proposed system. The sifted key rate and quantum bit error rate are 1.6 Mbps and 0.62%, respectively, at an operating speed of 100 MHz, rendering our system comparable to conventional systems using bulk‐optic devices for channel integration. [ABSTRACT FROM AUTHOR]

In the proposed protocol, a trusted entity interacts with the terminal device of each user to verify the legitimacy of the public keys without having access to the private keys that are generated and kept totally secret by the user. The protocol introduces challenge–response–pair mechanisms enabling the generation, distribution, and verification of cryptographic public–private key pairs in a distributed network with multi-factor authentication, tokens, and template-less biometry. While protocols using generic digital signature algorithms are proposed, the focus of the experimental work was to implement a solution based on Crystals-Dilithium, a post-quantum cryptographic algorithm under standardization. Crystals-Dilithium generates public keys consisting of two interrelated parts, a matrix generating seed, and a vector computed from the matrix and two randomly picked vectors forming the secret key. We show how such a split of the public keys lends itself to a two-way authentication of both the trusted entity and the users. [ABSTRACT FROM AUTHOR]

Big Data is a massive collection of data that require secure information transmission in the network. Hence, various existing Cryptography techniques have been used to improve information security in big data. However, the existing techniques cause data extrusion due to truncated transformation and diffusion properties in encryption and key generation processes that cause data leakage and loss. Hence, a novel Enhanced Encryption with Quantum-based Neuro Cryptography technique is introduced in which encryption is performed using logical shift and modulo operation based transformation that removes data extrusion and due to stream of photons in Quantum Cryptography Key has been generated and converted to the secret key via neuro cryptography. This process enhanced diffusion property and removed leakage and data loss. Moreover, malicious activities are happening due to inflexible encryption processes thus reducing confusion property that leads to delay and attack on nonresistance. Hence, a novel Inherited process with cyclic crossover operation has been developed in which one-point cyclic crossover and bit string mutation are achieved to combine ciphertext and key that increase confusion property and eliminate timing attack. The proposed system increases throughput and reduces encryption and decryption time with high diffusion and confusion properties. [ABSTRACT FROM AUTHOR]

In the era of digital proliferation, individuals opt for cloud servers to store their data due to the diverse advantages they offer. However, entrusting data to cloud servers relinquishes users' control, potentially compromising data confidentiality and integrity. Traditional auditing methods designed to ensure data integrity in cloud servers typically depend on Trusted Third Party Auditors. Yet, many of these existing auditing approaches grapple with intricate certificate management and key escrow issues. Furthermore, the imminent threat of powerful quantum computers poses a risk of swiftly compromising these methods in polynomial time. To overcome these challenges, this paper introduces a Quantum‐based Secure Key Communication and Key Generation Scheme QSKCG for Outsourced Data in the Cloud. Leveraging Elliptic Curve Cryptography, the BB84 secure communication protocol, certificateless signature, and blockchain network, the proposed scheme is demonstrated through security analysis, affirming its robustness and high efficiency. Additionally, performance analysis underscores the practicality of the proposed scheme in achieving post‐quantum security in cloud storage. [ABSTRACT FROM AUTHOR]

Highly efficient and spectrally pure single photon sources are desirable in fundamental studies of quantum physics and in many varied applications like in quantum metrology and quantum cryptography. 2D semiconductor colloidal quantum wells (CQWs) are quite appropriate as nanoscale photon sources because of their giant oscillator strengths and large absorption cross sections. The integration of such sources with dielectric metasurfaces exhibiting narrow resonances provides an excellent platform for highly efficient light‐matter interactions and the development of on‐chip light sources with high spectral purity. Here details on the use of capillary filling method are reported to achieve photonic coupling of CQWs to a metasurface resonator (MSR) featuring a square‐lattice geometry of holes on a slab‐waveguide to achieve strongly enhanced and almost spectrally pure emission of ≈3% of the original out‐of‐plane emission line‐width of the quantum emitters at room temperature. Long‐range exciton‐mediated photon transport facilitated by in‐plane slab waveguide modes is demonstrated and a theoretical basis to explain all the experimental data including that in terms of the MSR‐modified Lamb shifts and Purcell decays is provided. The results demonstrate a new platform with emergent photonic properties and suggest possibility of their use in on‐chip photonic quantum information processing. [ABSTRACT FROM AUTHOR]

Quantum networks that can perform user-defined protocols beyond quantum key distribution will require fully controllable entangled quantum states. To expand the available space of generated time-bin entangled states, we demonstrate a time-bin entangled photon source that produces qubit states | ψ 〉 = α | 00 〉 + β | 11 〉 with fully controllable phase and amplitudes. Eight different two-photon states have been selected and prepared from arbitrary states on the reduced two-qubit Bloch sphere. The photon pairs encoded in the time-bin scheme were generated at 2.4 MHz with a visibility of V = 0.9475 ± 0.0016 , with a violation of the CHSH Bell's inequality by 197 standard deviations. After entanglement distribution over 100 km of single-mode fibers, we obtained a visibility of V = 0.9541 ± 0.0113 with a violation of the CHSH Bell's inequality by 6 standard deviations. The prepared states had an average fidelity of 0.9540 ± 0.0016 at the source and an average fidelity of 0.9353 − 0.0209 + 0.0100 after entanglement distribution, which shows that the quantum states generated by our time-bin entangled photon source can be fully controlled potentially to a level applicable to long-distance advanced quantum network systems. [ABSTRACT FROM AUTHOR]

Digital signatures are one of the key cryptographic components for providing authenticity and non-repudiation. To circumvent the need of certificates, Shamir in 1984 introduced identity-based signature (IBS). Nearly all of the existing state-of-the-art IBS schemes are relying on the number-theoretic hardness assumptions. Unfortunately, these hard problems are insecure and face a threat in quantum world. Thus, it is high time to design and analyze IBS algorithms that can resist quantum attacks and provide long-term security. Quantum cryptography is one such technique to provide quantum-safe IBS. In this paper, we cryptanalyze the quantum cryptography-based IBS of Huang et al. (Huang et al. in Quantum Inf Process 22(1):36, 2022). We show that the design in (Huang et al. in Quantum Inf Process 22(1):36, 2022) is not secure against public key generator forgery attack, collusion attacks, and intercept and resend attacks. Next, we modify the design of (Huang et al. in Quantum Inf Process 22(1):36, 2022) and propose a new quantum IBS (namely qIBS) which is secure against the aforementioned attacks. [ABSTRACT FROM AUTHOR]

Quantum random number generation (QRNG) leveraging intrinsic quantum uncertainty has attracted significant interest in the field of integrated photonic architecture, with applications in quantum cryptography, tests of quantum nonlocality, and beyond. The demand for compact, low-energy consumption, robust, fast, and cost-effective QRNGs integrated into photonic chips is highlighted, whereas most previous works focused on bulk optics. Here, based on the metalens array entangled source, we experimentally realized a miniaturized, high-dimensional quantum random number generator via a meta-device without post-randomness extraction. Specifically, the device has a high-density output with 100 channels per square millimeter. This chip-scale quantum randomness source can obtain random number arrays without post-randomness extraction and enable compact integration for quantum applications needing secure keys or randomness. Our approach demonstrates potential in secure key generation and randomness for quantum applications. [ABSTRACT FROM AUTHOR]

Modern technologies like quantum and cloud computing have reshaped computing, offering immense power and scalability. While beneficial, they also challenge the security of traditional cryptographic systems. Quantum computing threatens RSA and ECC with algorithms like Shor's algorithm, which can accelerate computations exponentially. This risks exposing these systems to attacks, necessitating quantum-resistant cryptography. Cloud computing poses data security concerns, requiring robust cryptographic mechanisms and access controls. Lattice-based cryptography, leveraging problems like the Short Integer Solution (SIS), emerges as a solution. This paper presents a novel quantum-resistant public key encryption scheme based on ElGamal and SIS, ensuring security against quantum and classical threats in modern cryptographic environments. [ABSTRACT FROM AUTHOR]

With the rise of quantum computing, traditional cryptographic algorithms, such as the Elliptic Curve Digital Signature Algorithm (ECDSA), face potential vulnerabilities. Quantum computers could efficiently solve problems that are currently computationally infeasible for classical computers, thus threatening the security of cryptographic systems. As a result, there is a pressing need to develop quantumresistant cryptographic algorithms to ensure secure communication in a future where quantum computing is prevalent. ECDSA, widely used for securing digital communications, relies on elliptic curve cryptography to provide robust security through digital signatures. However, the advent of quantum computing poses a significant threat to ECDSA's security, as quantum algorithms such as Shor's algorithm could break the elliptic curve-based encryption by efficiently solving discrete logarithm problems. To address this issue, we propose a quantum-resistant cryptographic algorithm based on lattice-based cryptography. Our approach utilizes the Learning With Errors (LWE) problem, known for its resistance to quantum attacks. We implement the proposed algorithm and compare its performance with ECDSA in terms of key generation time, signing time, and verification time. The algorithm's security is analyzed against quantum attacks using theoretical and empirical methods. The experimental results demonstrate that the quantum-resistant algorithm provides a comparable level of security to ECDSA while offering significant advantages in the context of quantum resistance. Specifically, our quantum-resistant algorithm achieved key generation times of 120 ms, signing times of 150 ms, and verification times of 100 ms. In comparison, ECDSA showed key generation times of 80 ms, signing times of 90 ms, and verification times of 70 ms. Despite these performance trade-offs, the quantum resistance of the proposed algorithm ensures future-proof security for digital communications. [ABSTRACT FROM AUTHOR]

The cardinality of the private set allows multiple parties to jointly compute the cardinality of the intersection and union without revealing their respective private sets. It plays an important role in data mining and data analysis to protect privacy. However, existing studies only focus on computing the cardinality of the intersection or union of private sets. To extend its application in various scenes, a private‐set intersection and union mixed cardinality protocol are proposed for any tripartite based on Bell states for the first time. During the protocol, participants are supposed to be semi‐quantum to reduce the consumption of quantum resources and improve the realizability of the protocol. Furthermore, correctness and security analysis show that the protocol can withstand internal and external attacks. Additionally, the IBM Quantum Simulator (IBMQS) is also applied to illustrate the fundamentals of the protocol and verify the availability of the protocol. The results are expected have positive effects on the further development of secure multiparty computation. [ABSTRACT FROM AUTHOR]

A brief overview is presented of results obtained at the Rzhanov Institute of Semiconductor Physics in the development of photon detectors and emitters promising for use in quantum cryptography systems, along with miniature quantum frequency standards based on the effect of coherent population trapping. [ABSTRACT FROM AUTHOR]

In this work, we present a new protocol that accomplishes multiparty quantum private comparison leveraging maximally entangled | G H Z 3 〉 triplets. Our intention was to develop a protocol that can be readily executed by contemporary quantum computers. This is possible because the protocol uses only | G H Z 3 〉 triplets, irrespective of the number n of millionaires. Although it is feasible to prepare multiparticle entangled states of high complexity, this is overly demanding on a contemporary quantum apparatus, especially in situations involving multiple entities. By relying exclusively on | G H Z 3 〉 states, we avoid these drawbacks and take a decisive step toward the practical implementation of the protocol. An important quantitative characteristic of the protocol is that the required quantum resources are linear both in the number of millionaires and the amount of information to be compared. Additionally, our protocol is suitable for both parallel and sequential execution. Ideally, its execution is envisioned to take place in parallel. Nonetheless, it is also possible to be implemented sequentially if the quantum resources are insufficient. Notably, our protocol involves two third parties, as opposed to a single third party in the majority of similar protocols. Trent, commonly featured in previous multiparty protocols, is now accompanied by Sophia. This dual setup allows for the simultaneous processing of all n millionaires' fortunes. The new protocol does not rely on a quantum signature scheme or pre-shared keys, reducing complexity and cost. Implementation wise, uniformity is ensured as all millionaires use similar private circuits composed of Hadamard and CNOT gates. Lastly, the protocol is information-theoretically secure, preventing outside parties from learning about fortunes or inside players from knowing each other's secret numbers. [ABSTRACT FROM AUTHOR]

Abstract Artificial intelligence (AI) and classical machine learning (ML) techniques have revolutionised numerous fields, including quantum communication. Quantum communication technologies rely heavily on quantum resources, which can be challenging to produce, control, and maintain effectively to ensure optimum performance. ML has recently been applied to quantum communication and networks to mitigate noise‐induced errors and analyse quantum protocols. The authors systematically review state‐of‐the‐art ML applications to advance theoretical and experimental central quantum communication protocols, specifically quantum key distribution, quantum teleportation, quantum secret sharing, and quantum networks. Specifically, the authors survey the progress on how ML and, more broadly, AI techniques have been applied to optimise various components of a quantum communication system. This has resulted in ultra‐secure quantum communication protocols with optimised key generation rates as well as efficient and robust quantum networks. Integrating AI and ML techniques opens intriguing prospects for securing and facilitating efficient and reliable large‐scale communication between multiple parties. Most significantly, large‐scale communication networks have the potential to gradually develop the maturity of a future quantum internet.

Abstract Quantum key distribution (QKD) offers information‐theoretic security by leveraging the principles of quantum mechanics. This means the security is independent of all future advances in algorithm or computational power. However, due to the non‐availability of single‐photon sources, most traditional QKD protocols are vulnerable to various attacks, such as photon number‐splitting (PNS) attacks. Also, the imperfections in the measuring devices open a loophole for side channels that an eavesdropper may exploit to launch attacks such as large‐pulse attacks. As a result, this compromises the security of transmitted information. To address these challenges, the authors present a QKD protocol that is secure against both large‐pulse attacks and PNS attacks at zero‐error, in which the eavesdropper does not introduce any error, but still, the legitimate users of the system cannot distil a secure key. A notable feature of the proposed protocol is that it promotes greater robustness against both attacks than the Bennett‐Brassard 1984 (BB84) protocol or the Scarani‐Acin‐Ribordy‐Gisin 2004 (SARG04) protocol.

The ability to control the optical properties of a material with an electric field has led to optical memory devices, communication systems, optical signal processing, or quantum cryptography. Understanding electro-optic effects, especially in thin films, would improve the efficiency of these applications. In particular, the influence of epitaxial strains is of prime importance. In addition, the active control of these effects would be of great interest to tailor the material to the desired performance. Here, we demonstrate through first-principle calculations that the linear electro-optic response (Pockels effect) of two silicon-compatible ferroelectrics is stable with respect to bi-axial strain and that the electro-optic response can be strongly enhanced through the electrical control of the polarization. We attribute the former to the lack of optical phonon softening and a weak elasto-optic response and the latter to the externally induced softening of a phonon of symmetry A 1. Our results are readily applicable to other polar materials and show that the electro-optic effect can be efficiently engineered to meet the performance criteria of future technologies. [ABSTRACT FROM AUTHOR]

Shor's factorization algorithm (SFA) aims at finding the non-trivial factor of a given composite number, but the algorithm does not always work. In some cases, it has to call back to the beginning of the algorithm to make recalculation. After the analysis of the principle of SFA and the characteristics of RSA public-key cryptography with a series of data calculations, it can be concluded that the random value selected by the algorithm is closely related to whether the obtained period is effective. Therefore, a new optimized scheme is proposed to tackle with this defect from two perspectives: (a) When the a value is a perfect square, the algorithm can be completed with an odd cycle r. (b) When the period r obtained by the randomly selected a value is a multiple of 3 , the algorithm can be completed by modifying the decomposition method to relax the requirements for the period without affecting the complexity of the algorithm. Due to the limitations of hardware in applying the quantum algorithms, the classical algorithm is applied to simulate quantum algorithms to test the success rate of decomposition of some composite numbers. The result indicates the effectiveness of the improved algorithm, which significantly reduces the probability of repeated operations to save the quantum circuit resources. [ABSTRACT FROM AUTHOR]

Oblivious transfer (OT) is a significant two party privacy preserving cryptographic primitive. OT involves a sender having several pieces of information and a receiver having a choice bit. The choice bit represents the piece of information that the receiver wants to obtain as an output of OT. At the end of the protocol, sender remains oblivious about the choice bit and receiver remains oblivious to the contents of the information that were not chosen. It has applications ranging from secure multi-party computation, privacy-preserving protocols to cryptographic protocols for secure communication. Most of the classical OT protocols are based on number theoretic assumptions which are not quantum secure and existing quantum OT protocols are not so efficient and practical. Herein, we present the design and analysis of a simple yet efficient quantum OT protocol, namely qOT. qOT is designed by using the asymmetric key distribution proposed by Gao et al. (Opt Express 20(16):17411–17420, 2012) as a building block. The designed qOT requires only single photons as a source of a quantum state, and the measurements of the states are computed using single particle projective measurement. These make qOT efficient and practical. Our proposed design is secure against quantum attacks. Moreover, qOT also provides long-term security. [ABSTRACT FROM AUTHOR]

Conventional signcryption schemes that depend on discrete logarithm problem, big integer prime factorization, and bilinear pairing are at risk in the context of quantum computers. We suggest a signcryption scheme based on a lattice to overcome the problems posed due to potential quantum computers in healthcare management which is named as lattice-based ring signcryption scheme for smart healthcare management (LRS-SHM). Unlike existing schemes, our design uses regenerated keys for every signature generated by user itself (instead of a key generation center), thus protecting the privacy of the user. Furthermore, we provide an anonymous health record management scheme that combines a (t, n) threshold method with our lattice-based signcryption system in an effort to overcome the existing anonymity limits in health record administration, especially in light of quantum computing concerns. We show the anonymity of our lattice-based signcryption method against confidentiality and its existential non-forgeability against insider corruption in the context of health record administration, proving security under the random oracle model. We compare our proposed scheme with existing schemes and found that our scheme is more efficient than others. By the use of (t, n) threshold scheme, we protect our scheme from single point of failure because we distribute the secret share to n number of users and to reconstruct the secret the scheme requires at least t users. Empowering privacy, our lattice-based signcryption prevents quantum threats, introduces seamless key control, and enhances health record anonymity, setting a new standard for secure and efficient cryptographic solutions. [ABSTRACT FROM AUTHOR]

In the last couple of decades, Attribute-Based Encryption (ABE) has been a promising encryption technique to realize fine-grained access control over encrypted data. ABE has appealing functionalities such as (i) access control through encryption and (ii) encrypting a message to a group of recipients without knowing their actual identities. However, the existing state-of-the-art ABEs are based on number-theoretic hardness assumptions. These designs are not secure against attacks by quantum algorithms such as Shor algorithm. Moreover, existing Post-Quantum Cryptography (PQC)-based ABEs fail to provide long-term security. Therefore, there is a need for quantum secure ABE that can withstand quantum attacks and provides long-term security. In this work, for the first time, we introduce the notion of a quantum-secure ABE (qABE) framework that preserves the classical ABE's functionalities and resists quantum attacks. Next, we provide a generic construction of qABE which is able to transform any existing ABE into qABE scheme. Thereafter, we illustrate a concrete construction of a quantum ABE based on our generic transformation qABE and the Waters' ciphertext-policy ABE scheme. [ABSTRACT FROM AUTHOR]

Quantum identity authentication is one of the important branches of quantum cryptography. By means of the advantages of measurement-device-independent technique, in this paper, we propose a new two-party quantum identity authentication protocol, which is further extended to the multiparty quantum identity authentication protocol. It naturally removes the side-channel attacks caused by the detector loophole. Compared with the multi-party simultaneous quantum authentication protocols based on GHZ states, the proposed protocol may be more suitable for long-distance and large-scale multi-party authentication. [ABSTRACT FROM AUTHOR]

The leading countries across the world have entered the race to develop quantum technologies that will enable them to ensure their continued economic prosperity. Among these technologies, a special place is occupied by quantum communication, which is designed to ensure information security in an era where a quantum computer is capable of compromising a number of cryptography algorithms. In this article, this new digital technology includes quantum key distribution and encryption methods that are cryptographically resistant to a quantum computer. The study does not consider the regulation of the quantum communication sub-technology, the so-called “quantum internet,” due to the technical limitations of the existing equipment. The authors note that their predictions about the cryptographic strength of encryption algorithms are based solely on modern knowledge about the capabilities of quantum computing and do not take into account its hidden potential, for example, in terms of cryptanalysis information systems based on a machine learning model generated by a quantum computer. Currently, the only data protection system that is not subject to quantum threats is the technology of quantum key distribution. In today’s information and digital age, information security systems are an important element of critical infrastructure. Given the importance of these technologies, different states use different methods to regulate this field. This article puts forward and substantiates the hypothesis that the implementation of a combination of regulatory legal acts could have a greater positive impact on the development of quantum communication and ensure an acceptable level of information security in the post-quantum era. The analysis showed that a significant number of states and interstate associations are conducting research in this area, relying only on investment growth. This strategy has prevented any country from achieving the competencies of the People’s Republic of China. The authors also analyzed the methods of legal support used by China, Russia, and other countries in the field of quantum communication, which made it possible to identify a model of legal regulation of quantum communication that stimulates this technology’s development.

Quantum secure direct communication (QSDC) can directly transmit secret messages through quantum channel without keys. Device-independent (DI) QSDC guarantees the message security relying only on the observation of the Bell-inequality violation, but not on any detailed description or trust of the devices’ inner workings. Compared with conventional QSDC, DI-QSDC has relatively low secret message capacity. To increase DI-QSDC’s secret messages capacity, we propose a high-capacity DI-QSDC protocol based on the hyper-encoding technique. The total message leakage rate of our DI-QSDC protocol only relies on the most robust degree of freedom. We provide the numerical simulation of its secret message capacity altered with the communication distance. Our work serves as an important step toward the further development of DI-QSDC systems.

The field of computing is about to undergo a revolution thanks to quantum computing, a ground-breaking innovation based on the ideas of quantum physics. The enormous implications and potential that quantum computing has for cloud computing are explored in this publication. We examine the difficulties faced by current cryptography systems as well as prospective improvements in fields like machine learning, simulations, and data security as we delve into the basic alterations in computing paradigms. Additionally, we go over the revolutionary possibilities for cloud computing, such as the creation of quantum-safe cloud security solutions, hybrid computing models, and quantum cloud services.

Abstract The quantum communication channel is considered to be eavesdropped when the signal Quantum Bit Error Rate (QBER) exceeds a defined theoretical limit and is thus considered a figure of merit parameter for assessing the security of a quantum channel. This work presents a general mathematical model considering device imperfections and various sources of errors for estimating signal QBER in polarisation encoded satellite‐based QKD systems. QBER performance for satellite‐to‐ground downlink scenarios has been investigated for multiple sky brightness conditions (day time and night time operations), two operating wavebands: 800 and 1550 nm as well as for different quantum transmitter and quantum receiver architectures. Further, a novel QBER estimation analysis for inter‐satellite QKD links has also been presented. The estimation results obtained from the developed model have been validated against and found in good agreement with the measured results of the only reported satellite‐to‐ground QKD experiments till date. The presented QBER modelling and analysis will aid in system engineering and efficient design of future satellite‐based QKD systems.

The Quantum Key Distribution (QKD) network approach has emerged as a promising solution and has garnered significant interest across various domains. QKD networks can be broadly categorized into two main types: those based on measurement-device-dependent (MDD) protocols and those based on measurement-device-independent (MDI) protocols. A novel network scheme is proposed combining these two protocols to guarantee end-to-end secure communication. It comprises two interconnected networks — the first uses a measurement-device-dependent protocol to connect routers with nearby nodes, while the second employs a measurement-device-independent protocol to interconnect the routers. In the first network, the process begins with Alice (Router) generating two types of weak quantum signals — the first has intensity, frequency and polarization or phase randomly varied, while the second with different delay times. Alice randomly transmits either signal states carrying information or decoy states with varying properties to the receivers (Bobs) over the quantum channels. She also sends a synchronization signal along with the quantum signals. At the receiver end, the synchronization pulse timestamps the incoming quantum signals. Each Bob then randomly shifts the frequencies of the received signals and measures their phase/polarization of the first signal and measures the delay times of the second signal. The secret key is derived by combining the frequency, the delay time and the phase/polarization information of the quantum signals, resulting in longer key lengths. Encoding information across multiple degrees of freedom enables extended key generation for secure communication. However, between the routers, MDI-QKD protocols are used to securely share the keys. This hybrid approach aims to ensure secure end-to-end communication across the network. [ABSTRACT FROM AUTHOR]