This comprehensive review examines the latest advances in quantum technologies across three interconnected domains: quantum computing (NISQ devices, variational quantum algorithms, and quantum machine learning), quantum cryptography (NIST post-quantum cryptography standards, quantum key distribution, and advanced protocols like Quantum Permutation Pad), and quantum sensing (quantum dot-based sensors, NV-center magnetometry, atomic clocks, and energy applications). It highlights the convergence of these fields through quantum networks and distributed architectures while addressing key challenges such as decoherence, scalability, and error correction. An excellent resource for researchers seeking an integrated overview of quantum computing, security, and sensing developments (2020–2026).
This comprehensive review examines the latest advances in quantum technologies across three interconnected domains: quantum computing (NISQ devices, variational quantum algorithms, and quantum machine learning), quantum cryptography (NIST post-quantum cryptography standards, quantum key distribution, and advanced protocols like Quantum Permutation Pad), and quantum sensing (quantum dot-based sensors, NV-center magnetometry, atomic clocks, and energy applications). It highlights the convergence of these fields through quantum networks and distributed architectures while addressing key challenges such as decoherence, scalability, and error correction. An excellent resource for researchers seeking an integrated overview of quantum computing, security, and sensing developments (2020–2026).
Quantum technologies are moving from foundational science toward engineered systems in sensing and metrology, computing and simulation, communication and networking, and security. The transition is uneven in technological maturity: atomic clocks and several quantum sensors are operational; quantum key distribution has reached field deployment but remains constrained by integration, assurance and network architecture; post-quantum cryptography is entering standards-based migration; and general-purpose fault-tolerant quantum computing remains an engineering objective despite major progress in error correction. This treatise develops a mathematically grounded and application-oriented account of what quantum technologies are, what physical resources they exploit, what advantages have been proved or demonstrated, and where claims remain speculative. It distinguishes among scientific feasibility, engineering readiness, operational utility, economic value and societal legitimacy. Across fundamental physics, Earth and space sciences, environmental monitoring, health and life sciences, cybersecurity, critical infrastructure, hazards, defense, finance, decision support and AI-enabled systems, this work identifies bottlenecks and proposes a systems roadmap for robust, scalable, efficient, verifiable and responsible quantum-enabled capabilities.
Abstract Quantum computing exploits superposition and entanglement to process information in an exponentially large state space, enabling algorithms such as Shor’s to factor large integers efficiently and thereby undermining RSA and elliptic curve cryptography. Quantum cryptography, here encompassing post quantum cryptographic (PQC) algorithms and quantum key distribution (QKD), is a leading candidate for protecting data against quantum capable adversaries. PQC designs classical schemes conjectured to be secure against both quantum and classical attacks, whereas QKD uses quantum mechanics to detect eavesdropping and establish information theoretically secure keys. Existing literature and limitations. Recent surveys summarise PQC families and the standardisation process led by the U.S. National Institute of Standards and Technology (NIST), and reviews outline QKD protocols and their challenges. However, most prior work either addresses narrow subtopics or does not systematically synthesise empirical evidence across technical and application domains. As a result, there is still limited integrated understanding of key issues, technologies, mathematical foun dations, algorithms, programming tools and real world deployments. Objective and contributions of this review. This study systematically analyses 61 peer reviewed journal articles published within the last five years that focus on quantum cryptography. Using Covidence to manage study identification, selection, quality assessment, data extraction and narrative synthesis, it (a) characterises current issues and challenges; (b) surveys recent technological advancements and implementations; (c) evaluates algorithmic approaches and their effectiveness; (d) examines the underlying mathematical models; (e) maps the programming languages and tools used to implement quantum schemes; and (f) synthesises evidence on practical applications and future research directions. The review integrates findings on PQC and QKD, highlights gaps in the current evidence base, and offers practitioners, scholars and policymakers guidance for developing quantum secure communication systems. Keywords Quantum cryptography, Post quantum cryptography, Quantum key distribution, Systematic literature review, Quantum secure communication
The rapid advancement of quantum computing presents both unprecedented opportunities and significant threats to modern cybersecurity. As quantum processors progress toward practical large-scale deployment, widely used cryptographic systems, particularly RSA, ECC, and other public-key mechanisms, face the risk of becoming obsolete. This review examines how quantum technologies can be strategically leveraged to enhance cybersecurity while simultaneously addressing the vulnerabilities introduced by quantum-enabled attacks. A systematic analysis of 35-40 peer-reviewed studies was conducted to evaluate developments in post-quantum cryptography, quantum-resistant security protocols, Quantum Key Distribution (QKD), and hybrid classical–quantum defense architectures. The findings reveal a rapidly evolving research landscape focused on resilient lattice-based cryptography, scalable quantum-safe communication frameworks, and early-stage quantum machine learning applications for intrusion detection. The review highlights both the promise and current limitations of quantum-driven security solutions, including hardware constraints, integration challenges, and the need for global standardization. The study underscores the urgency for governments, industries, and researchers to adopt quantum-ready cybersecurity strategies and accelerate the transition to quantum-resilient infrastructures.
The rapid advancement of quantum computing poses a significant threat to classical cryptographic systems that rely on the computational hardness of mathematical problems such as integer factorization and discrete logarithm problems. In this context, quantum cryptography has emerged as a promising paradigm for secure communication based on the fundamental principles of quantum mechanics rather than on computational assumptions. This paper presents a comprehensive review of quantum cryptography, with a particular focus on Quantum Key Distribution (QKD), the most mature application. The study discusses the theoretical foundations of quantum security, including superposition, entanglement, and the No-cloning theorem, which collectively enable eavesdropping detection and guarantee information-theoretic security. Furthermore, the review examines major QKD protocols, such as BB84 and E91, as well as their advanced variants designed to address practical vulnerabilities and enhance performance. Recent progress in real-world implementations, including fiber-optic networks, free-space communication, and satellite-based systems such as the Micius satellite, is also analyzed. In addition, the paper highlights critical challenges related to scalability, hardware limitations, and security loopholes arising from imperfect devices. Finally, emerging research directions, including hybrid cryptographic frameworks that integrate quantum and post-quantum approaches, are discussed to provide insights into the future of secure communication. This review aims to provide a structured, up-to-date understanding of quantum cryptography, bridging the gap between theoretical developments and practical implementations, and emphasizing its crucial role in shaping next-generation cybersecurity systems.
Quantum computing leverages quantum mechanical concepts, including superposition, entanglement, and interference, to solve problems that traditional computers cannot handle efficiently. This study presents a comprehensive overview of the field, covering both the theoretical foundations and the latest developments in quantum hardware and algorithms. This study covers fundamental elements, qubits, gates, and circuits while emphasizing quantum parallelism as a distinctive feature. To illustrate efficiency gains, we explore notable algorithms like Shor’s factorization procedure and Grover’s search algorithm. Furthermore, we analyze recent advancements in quantum hardware, focusing on superconducting qubits, trapped ions, and photonic quantum computers, with an emphasis on implementations by IBM, Google, and other industry leaders. The discussion also addresses major challenges such as decoherence, noise, and the need for quantum error correction to achieve fault tolerance. Finally, we explore emerging applications in cryptography, optimization, quantum machine learning, and material simulation, and identify critical open problems that must be addressed to realize scalable, universal quantum computing. Our review underscores the transformative potential of quantum technologies across science and industry.
Quantum computing, grounded in the principles of superposition and entanglement, has emerged as a revolutionary paradigm with the potential to outperform classical systems in specific computational tasks. This paper presents a comprehensive survey of the foundational concepts, algorithmic developments, hardware architectures, and programming ecosystems in quantum computing. We analyze the current progress in key application areas such as cryptography, machine learning, optimization, and quantum chemistry. Furthermore, we review recent advances between 2023 and 2025, including developments in fault-tolerant architectures and quantum error correction. The paper also discusses the significant technical challenges that hinder large-scale practical deployment, including qubit scalability, decoherence, and programming limitations. By synthesizing literature across disciplines, this review aims to provide a holistic understanding of the quantum computing landscape and outline critical directions for future research and integration with classical systems.