Abstract: In an era where quantum computing is poised to revolutionise computational capabilities, the security of naval communication networks faces unprecedented threats. Quantum Key Distribution (QKD) and Post-Quantum Cryptography (PQC) emerge as pivotal technologies in safeguarding sensitive military communications from the formidable capabilities of quantum computers. This paper explores the imperative for adoption of QKD and PQC within naval networks, delving into the technological principles, global adoption, and strategic advantages of these cryptographic solutions. The authors present a comprehensive overview of the advancements and initiatives undertaken by leading global naval and military forces and outline a roadmap for the implementation of QKD and PQC in Indian Naval networks. The paper also addresses the technical, operational, and strategic challenges associated with these technologies, offering insights into overcoming these hurdles. Through this, the essay underscores the necessity of adopting QKD and PQC to ensure the long-term security and resilience of naval communications in the face of evolving quantum threats.

Introduction

Quantum computing presents a looming threat to conventional cryptographic systems which are the backbone of secure communications today. As quantum computers advance, they are poised to break widely used existing encryption algorithms, necessitating a transition to quantum-resistant solutions. This paper delves into two promising approaches to quantum-safe cryptography: Quantum Key Distribution (QKD) and Post-Quantum Cryptography (PQC). QKD utilises fundamentals of quantum physics to ensure secure key exchange with the unique ability to detect eavesdropping, while PQC focuses on developing new cryptographic algorithms resistant to quantum attacks, compatible with existing infrastructure. This paper explores the theoretical foundations, practical implementations, and current challenges associated with both QKD and PQC. Furthermore, the paper examines their potential integration into naval networks, highlighting the benefits and obstacles in adopting these technologies to safeguard military communications against future quantum threats. The aspect of revisiting existing methodologies for physical key distribution, as required by the Scientific Analysis Group (SAG), is also briefly discussed. Through this comprehensive analysis, the authors aim to provide a clear roadmap for the deployment of QKD and PQC in securing critical infrastructure in the quantum era.

Communication Security Protocols and Cipher Management

Several armed forces around the world employ a variety of communication security protocols to ensure safe and encrypted communications, tailored to their specific operational requirements and security needs. The Indian Navy also relies on a variety of sophisticated algorithms and security protocols to achieve secure voice and data communication, crucial for facilitating communication between naval assets, command centres, and other branches of the armed forces, both in peacetime and during military operations. The primary types of networks utilised include terrestrial and satellite networks, at tactical as well as higher levels, each serving distinct roles in the broader naval communication framework.

  • Terrestrial Networks. Terrestrial networks in the IN encompass Local Area Networks (LANs) and Metropolitan Area Networks (MANs), essential for connecting various naval installations on land. These networks enable real-time data sharing, secure voice and video communication, and access to centralised databases and applications, which are critical for operational planning and coordination. These networks largely rely on bulk encryption devices, installed at the various Communication Centres.

  • Tactical Networks. Tactical networks facilitate sharing of real-time tactical information, that are essential for Command and Control (C2) functions for all types of deployed assets. These networks use secure line-of-sight radio communication systems and provide analogue and digital voice and data services to users. Modern tactical communication systems incorporate both hardware and software encryption as well as anti-jamming technologies to protect against interception by adversarial forces.

  • Satellite Networks. Satellite networks form the backbone of long-range communication for the Indian Navy. They are indispensable for real-time situational awareness, and key enablers for Command and Control of blue-water naval operations. The Navy’s satellite-based communication service facilitates secure voice, data and video communication. This secure and encrypted communications channel also protects critical command and control systems from cyber threats.

Some of the prominent protocols and technologies used to secure these critical communications networks include AES (Advanced Encryption Standard) and RSA (Rivest-Shamir-Adleman). AES, known for its robustness and efficiency, is widely employed for encrypting sensitive data -- from personal messages to financial transactions -- while ensuring confidentiality and integrity. AES operates through symmetric key encryption, where both the sender and receiver share the same secret key for encryption and decryption. Its strength comes from its ability to handle large blocks of data efficiently while undergoing rigorous scrutiny by cryptographic experts and organisations to ensure it can withstand known attack methods. AES is efficient and well-suited for encrypting large amounts of data, such as files, disks, and data transfer over networks. RSA, on the other hand, is pivotal in establishing secure connections and authenticating identities through asymmetric encryption. RSA is used primarily for secure key exchange and digital signatures for important documents or messages to verify their origin and integrity, as well as in establishing secure communication channels and ensuring the authenticity of transmitted data.

A Navy-wide cipher management organisation directs the generation, distribution, implementation, accounting and withdrawal of the various cipher modules and encryption keys that underpin the security overlay of the Navy’s vast communications network. After distribution of digital cipher modules across users, all communication networks described above viz. terrestrial, tactical and satellite, use a variety of key-exchangemechanism to undertake encryption and decryption of digital data. This organisation is highly streamlined and has satisfactorily met the needs of the Service in a pre-quantum age.

These communication security and cipher management protocols and organisations are integral to ensuring the operational security, mission success, and protection of sensitive information for the IN. They undergo rigorous testing, certification, and continuous development to stay ahead of evolving threats and ensure the resilience of military communication networks against sophisticated adversaries. The advent of Quantum Computing, however, raises new questions regarding the resilience of existing protocols and their continued relevance in a quantum era.

Quantum Computing and the Threat to Existing Crypto Algorithms

Quantum computing has seen rapid advancements in recent years, with significant strides made by researchers working for institutions, corporations and technological laboratories. Quantum computers differ from other computers by using qubits instead of bits as their smallest data unit. In accordance with the properties of superposition and entanglement, qubits can exist in multiple states at once, allowing quantum computers to process large amounts of information at incredible speeds. In 2019, Google demonstrated the potential of quantum computing by achieving "quantum supremacy." The firm developed a 54-qubit processor named "Sycamore," designed with fast and accurate quantum logic gates. This processor completed a specific computation in 200 seconds, a task that would take the fastest classical supercomputer up to 10,000 years to produce a similar output.1 These developments have profound implications for cryptographic systems. Algorithms such as Shor's Algorithm enable quantum computers to factor large integers efficiently, thereby breaking widely used key exchange cryptographic schemes like RSA and ECC, which rely on the difficulty of such problems for their security.2 This impending threat necessitates the exploration and adoption of quantum-resistant cryptographic methods to secure data in the post-quantum era.

Ensuring Secure Communications in a Quantum World

Across the world, security agencies are collaborating with industry partners and academic institutions at the cutting-edge of research, to overcome the threat posed by Quantum Computing to existing security algorithms. Towards securing existing communication systems against Quantum Computing, two broad approaches are under parallel development: -

  • Quantum Key Distribution (QKD). The use of Quantum Physics to exchange crypto keys in a secure and tamper-proof manner, thereby augmenting existing key-exchange algorithms to authenticate transactions.

  • Post Quantum Computing (PQC). The use of complex mathematical algorithms that are resistant to code breaking by Quantum Computers.

Quantum Key Distribution

Quantum Key Distribution (QKD) is an innovative approach to secure communication that uses the principles of quantum mechanics to enable two parties to produce a shared random secret key, which can then be used to encrypt and decrypt messages. Unlike classical cryptographic methods, QKD offers theoretically unbreakable security, as any attempt to eavesdrop on the key exchange can be detected by the communicating parties.

QKD leverages the properties of quantum particles, particularly photons, to ensure the security of key distribution. When two parties wish to share a secret key, they use a QKD protocol to exchange qubits. If an eavesdropper or Man in The Middle (MiTM) tries to intercept the qubits, their act will disturb the quantum states of the qubits, introducing detectable anomalies. Upon comparison of a subset of their exchanged qubits, these anomalies will be detected by the two communicating nodes, thereby indicating the presence of a “Man in the Middle.” This is the essence of the BB84 QKD Protocol introduced by Charles Bennett and Gilles Brassard in 1984. Over time, advancements in technology and understanding of quantum mechanics have led to the development of more efficient and practical QKD protocols that address specific challenges such as noise, loss, and implementation complexity, including the E91, B92 and SARG04.3

Global Achievements in QKD and Initiatives. While various countries have been focussing on research into QKD, this technology has matured and translated from the labs and academia into communication and network solutions in a few nations.

  • In Europe, the efforts have been led by countries such as Switzerland, Austria, and the UK. In Switzerland, the University of Geneva has conducted groundbreaking experiments demonstrating the feasibility of QKD over metropolitan fibre networks, pushing the boundaries of secure quantum communication.4 The Austrian Institute of Technology has contributed to advancing QKD protocols and implementing them in practical scenarios, bolstering Europe's leadership in quantum-secured communication. SECOQC (Secure Communication based on Quantum Cryptography) established the first QKD network in Vienna in 2008, connecting six locations across the city over a total distance of 83 km.5 In the UK, a Quantum Communications Hub was set up in 2014 as a part of the UK's National Quantum Technologies Programme, focusing on developing and deploying QKD technologies.6 In 2019, a successful demonstration of QKD over 421 km of standard optical fibre was undertaken at the UK Quantum Technology Testbed.7

  • In North America, the United States and Canada have invested heavily in QKD research and development. Institutions such as the National Institute of Standards and Technology (NIST) in the US have been pivotal in setting standards for QKD protocols and advancing quantum cryptography. In 2003, the Defence Advanced Research Projects Agency (DARPA) developed the Quantum Network Testbed, demonstrating the practical application of QKD over a 10 km fibre optic link in Boston amongst 10 interoperable nodes.8 A decade later, the Los Alamos National Laboratory successfully deployed QKD systems over 48 km of installed optical fibre in 2023, enhancing secure communication for critical infrastructure.9 Building upon these achievements, the US Department of Energy (DOE) unveiled the Quantum Internet Blueprint, aiming to create a nationwide network leveraging QKD for secure communications.10 Canada has been at the forefront of advancing Quantum Key Distribution (QKD) through groundbreaking initiatives like the Quantum Encryption and Science Satellite (QEYSSat) project. Launched by the Canadian Space Agency (CSA), QEYSSat aims to demonstrate the viability of quantum encryption via satellite, providing a secure method of communication across both remote and urban areas. This initiative highlights Canada’s strong commitment to establishing quantum-secure communication networks, particularly across vast geographies where fibre-based solutions may be impractical.

  • China has also emerged as a powerhouse in QKD research and implementation. Chinese researchers have achieved significant milestones, including the development of satellite-based QKD systems like the Micius satellite. Launched in 2016, it enabled the world's first intercontinental QKD link between China and Austria, demonstrating secure communication over 7,600 km paving the way for ultra-secure communications on a global scale.11 In the same year, a 2,000 km QKD network connecting Beijing and Shanghai was inaugurated, enabling secure communications between government and financial institutions in these centres of Chinese governance and finance.12 The following year, the European Space Agency’s collaboration with China to demonstrate satellite-based QKD bore fruit, with the QUESS satellite achieving secure communications over 1,200 km.13 Even more significantly, field trials of QKD systems were undertaken in urban commercial fibre-optic networks, including a 404 km link in the city of Hefei, showcasing practical implementation in real-world settings.14

Across these regions, QKD continues to evolve from theoretical concepts to practical implementations, addressing challenges such as key distribution over long distances, network integration, and scalability. As countries continue to invest in QKD research, development, and deployment, the technology holds promise not only for enhancing cybersecurity but also for shaping the future landscape of secure communication infrastructures worldwide, ensuring privacy and integrity in the digital age.

India's Forays in QKD

India is making forays into the field of Quantum Key Distribution (QKD), demonstrating its capability and commitment to secure communications. The Union Government announced the National Quantum Mission (NQM) in April 2023 from 2023-24 to 2030-31with a total financial outlay of Rs. 6003.65 Crore.15 The mission seeks to initiate, support, and expand scientific and industrial R&D while building a dynamic and innovative ecosystem in Quantum Technology (QT). Key goals include establishing secure quantum communication between satellite-based ground stations over 2000 kilometres within India, enabling secure long-distance communications with other countries, implementing inter-city quantum key distribution over 2000 kilometres, and developing multi-node quantum networks with quantum memories. An overview of India's key achievements and initiatives in the field of QKD is as follows:

  • CDoT. CDOT (Centre for Development of Telematics) has made notable progress in the field of Quantum Key Distribution (QKD), focusing on developing indigenous technologies to enhance cybersecurity in India. CDOT has been actively involved in developing QKD prototypes tailored for secure communication applications. These prototypes involve the integration of advanced quantum optics components, photon detectors, and secure key distribution algorithms. C-DOT’s QKD link has been live in New Delhi between Sanchar Bhawan and NIC Headquarters (CGO Complex) since February 2023.16

  • Physical Research Laboratory (PRL). Physical Research Laboratory (PRL) is a 75-year-old premier research institute under the Department of Space (DOS), and is regarded as the cradle of space sciences in India. It has been working on utilising space for quantum secure communication with support from the DOS and the Department of Science and Technology (DST). In the process of moving towards satellite-based quantum communication, it has demonstrated free-space QKD with entangled photons and the effect of atmosphere on the secure key rate over a distance of 200 meters. Further, the institute has recently been able to demonstrate end to end quantum encryption over a distance of 300 meters using an indigenously developed entangled photon source.

  • Qnu Labs (2016). QNu Labs is India's first quantum-resilience company. It has developed and deployed commercial QKD systems for secure communication in various sectors, including defence, banking, and telecommunications. In 2022, QNu Labs secured a contract with the Indian Army to provide their 'Armos' QKD system. This system includes a pair of Armos boxes that create and transmit secure encryption keys using quantum mechanics.17 The introduction of this technology aims to protect sensitive data, leveraging quantum physics to ensure unbreakable security even against quantum computers.18 In May 2023, QNu Labs signed a significant contract with the Indian Navy to procure and deploy QKD-based systems in a Hub & Spoke configuration across multiple locations. This makes the Indian Navy the first agency in the country to procure large-scale quantum-based encryption systems.19 The deployment of these systems aims to secure the Navy's communication networks against potential threats. Further, QNu Labs' suite of quantum secure products and solutions includes Quantum Key Distribution (QKD), Trusted Nodes (TNs), and Quantum Random Number Generator (QRNG) systems. These technologies provide hardware and software-based products that leverage quantum and post-quantum cryptography advantages.20

Challenges in Implementation of QKD. Despite their seeming robustness, implementation of BB84 and other QKD protocols in real-world environments presents challenges related to hardware requirements, operational complexities, and scalability. While providing an optimal solution for ultra-secure key distribution, the following challenges exist in implementation of QKD: -

  • Technical complexity of quantum-compatible optical hardware, for the generation and detection of synchronised quantum signals.

  • Transmission losses, as quantum signals are vulnerable to attenuation over large distances.

  • Noise and Interference, since such signals are particularly susceptible to noise sources such as background light and thermal effects.

  • Key Rate, or rate of generation of quantum cryptographic keys, is directly related to the efficiency of the optical hardware, noise-shielding, and fidelity over transmission media. Increasing the key generation rate while maintaining security and efficiency is a persistent challenge in QKD implementation.

  • Integration of QKD into existing communication networks and protocols, and scaling QKD technology for widespread deployment at an affordable cost are major challenges that will determine the practical adoption of the technology into military communication systems. Addressing these challenges requires continued research and development efforts, collaboration across interdisciplinary fields, and advancements in quantum technologies, photonics, and cybersecurity practices. Overcoming these challenges will be crucial for realizing the full potential of Quantum Key Distribution in enhancing the security of communication networks and critical infrastructure in the future digital landscape

Post Quantum Cryptography. Whilst QKD solves the problem of establishing secure communication channels and digital signature authentication between parties through tamper-proof quantum key-exchange by using laws of physics which cannot be manipulated, there are inherent challenges in implementation of QKD devices and issues of maintaining high SNR as brought out above. Meanwhile, the vulnerability of existing mathematical algorithms that underpin globally employed security protocols to increasingly advanced quantum computers continue to rise. A parallel line of effort, therefore, involves the development of mathematical algorithms of sufficient complexity such that even Quantum computers are unable to decode them in a given time period. This is termed Post Quantum Cryptography (PQC) and is complementary to the developments in QKD. At present, PQC algorithms are aimed at asymmetric encryption and will replace RSA and ECC which are being used by NIST.

PQC Implementation Techniques. PQC algorithms are being actively researched and standardized by organisations such as the American NIST (National Institute of Standards and Technology) to ensure that they meet stringent security requirements and can be integrated into existing cryptographic protocols and infrastructure. One of the most promising approaches within PQC is lattice-based cryptography, which involves complex mathematical problems set in high-dimensional lattices. These problems, like the Shortest Vector Problem (SVP), are computationally difficult to solve, even with the power of quantum computers.

In lattice-based cryptography, encryption is built on the difficulty of finding the nearest point in a high-dimensional lattice, a task that becomes exponentially harder as dimensions increase. Lattice-based cryptographic systems, such as Kyber, are already being considered by standards organizations like NIST as candidates for post-quantum security. By leveraging the inherent complexity of lattice problems, PQC ensures future-proof encryption, providing resilience against the immense computational capabilities of quantum machines.

Roadmap for Implementation of QKD and PQC-based Secure Communications in the Indian Navy.

Having established how current digital communication systems are at risk from cyber-attacks by quantum computers as the computational power in Quantum computers can decode algorithms like RSA and ECC, the two main approaches being explored globally in quantum cryptography, the following considerations are of salience when looking at QKD and PQC as possible solutions to safeguard digital communications in the Indian Navy:-

  • Deployment of Indigenous QKD Systems. India currently relies on traditional cryptographic algorithms such as RSA and ECC for securing digital communications and also distribution of keys using a physical means which is a cumbersome procedure especially for key management. As mentioned earlier, these algorithms could be attacked by quantum computers in the future, making the switch to QKD-based key exchange systems imperative. QKD is particularly relevant for securing high-value and long-term sensitive communications where absolute security guarantees are paramount. Accordingly, the development, procurement and deployment of QKD-based systems for critical information exchange between C2 nodes needs to be pursued with utmost alacrity. The Indian Navy has taken the lead in this endeavour, with the procurement of indigenous QKD systems developed by QNu Labs that will be deployed in a hub-and-spoke model at critical Naval Command and Control nodes across the country, thereby ensuring secure authentication and key-exchange.21 While ranges are limited to 200 km at present, research on the use of quantum repeaters to extend the range to 1000 Km is ongoing.

  • Development of Space-Based QKD Systems. While initial steps in deployment of terrestrial QKD-based encryption systems have been progressed by various agencies in the country, the limited distances feasible through current systems places constraints on the suitability of terrestrial QKD for pan-Navy implementation. Space-Based QKD has emerged as the preferred line of research for meeting real-world requirements across vast geographical distances. In India, ISRO-SAC reached a critical milestone in March 2020 when it demonstrated free- space quantum communication across a 300-meter distance.22 Building on this accomplishment, Physical Research Laboratory is in the process of developing space-based QKD communication systems. Having developed its own free-space QKD system, QNu Labs is collaborating with ISRO towards the development of space-based QKD and is likely to achieve fruition by 2026.23

  • Implementation and Integration of PQC Algorithms. PQC algorithms are under research and standardisation to ensure they meet security standards and can be seamlessly integrated into existing protocols and systems. This process includes optimising for performance, ensuring compatibility, and facilitating large-scale deployment across diverse applications. Towards this, the Indian Navy would need to collaborate actively with academia and industry partners to review the R&D efforts to refine these algorithms in order to meet SAG/ CPC requirements, and program the algorithms into existing cipher equipment. These algorithms can then be scaled and distributed through existing cipher distribution channels as previously established. This methodology would necessitate minimal changes in existing cipher architecture of the IN and would pave the way for quantum-resistant technology absorption to safeguard our digital communications.

  • Joint Training in Quantum Cryptography. The establishment of a Quantum Lab at the Military College for Telecommunications Engineering (MCTE) at Mhow (MP), paves the way for enabling joint training in various fields of study related to quantum technologies to be undertaken at MCTE.24 Close integration with industry partners that are pioneering developments in the field is essential towards focusing the research efforts on tangible deliverables that meet the communications security requirements of the three Services. Further, the Defence Institute of Advanced Technology (DIAT) at Pune has also established a School of Quantum Technology, with research being undertaken in the field of quantum cryptography. Collaboration between all stakeholders, would enable rapid absorption of quantum-related technologies within the Armed Forces.

  • Review of Key Distribution Modalities. The Scientific Analysis Group (SAG), a research institution under India's Defence Research and Development Organization (DRDO), has outlined stringent security requirements for cryptographic systems, in order to safeguard national security interests. SAG emphasises the necessity for robust cryptographic algorithms that can withstand sophisticated attacks, thereby ensuring the confidentiality, integrity, and authenticity of sensitive information. Among these requirements is the implementation of strong key management protocols, including secure key generation, storage, distribution, and lifecycle management. Some of these techniques while effective, suffer from cumbersome key management challenges. One of the main aspects of secure key distribution is to avoid a Man in The Middle (MiTM) attack. In a MiTM attack, the interceptor can read and modify messages without detection, potentially leading to severe security breaches, especially in sensitive contexts such as military communications. Quantum Key Distribution, however, offers a solution to address the MiTM issue. By the inherent nature of quantum physics, any attempt to intercept the qubit stream will result in a change in the bits and reveal the presence of an eavesdropper as explained earlier. QKD, therefore, is immune to MiTM attacks. Accordingly, utilisation of QKD to detect MiTM attacks is an area which must be explored by SAG.

Recommendations

The following recommendations aim to mitigate the looming threat of Quantum Computing-driven breaches of Naval cyber infrastructure, in a cost-effective, implementable and scalable way:

  • QKD-based Secure Networks. QKD systems promise the most secure means of cryptographic key-exchange in a quantum computing world. This could be implemented across two physical media. These are:

    • Terrestrial QKD Networks. QKD kits capable of cohabitating existing Naval Communication Network (NCN) fibre-optic networks may be deployed to secure communications between major naval C2 nodes such as MOCs and COMNETCENs. Integration of quantum repeaters at suitable distances can further extend the ranges and accordingly dialogue must be initiated with industry and academia to implement these technologies.

    • Space-Based QKD. The induction of satellite-based QKD will facilitate long-distance loss-free secure key-exchange, thereby mitigating the challenges of terrestrial QKD communication. Indigenous industry estimates place its development in the near future, with the technology likely to be ready for trials by 2026.

  • PQC-based Algorithms. Development of indigenous PQC-based algorithms that can resist attacks by quantum computers may be made a key national cybersecurity mission, led by the NSCS. This will create a coordinated approach involving the Ministries of Defence, Electronics & Information Technology (MeitY) and other related agencies of the GoI. As the primary advantage of PQC is its compatibility with existing cipher architecture, focus on this line of research will enable rapid deployment of quantum-resistant cipher algorithms through existing cipher-distribution mechanisms. This makes it a preferred choice for securing information in a quantum computing age, for large organisations such as the Armed Forces.

  • Tamper/ Computer Resistant Framework. Along with the distribution of QKD kits, the following methodology for distribution of keys is recommended to be adopted:

    • As the fundamental laws of physics render QKD tamper-proof, the guidelines for distribution of keys should incorporate QKD networks as the primary key-exchange mechanism between Key Generation and Key Distribution Centres.

    • With the ongoing development of QKD devices in India, SAG may be tasked to commence security grading of QKD devices, in sync with their development cycle. Additionally, with NIST likely to finalise PQC algorithms by December 2024, SAG may also be tasked with creating a framework to assess domestic PQC-based algorithms, to protect critical national infrastructure without the reliance on US NIST-based algorithms, and the ever-prevalent threat of backdoors.

  • Joint Training and Industry Collaboration. Closer collaboration with research bodies and industry partners in the quantum laboratories at DIAT and MCTE will lead to technology absorption amongst Armed Forces personnel involved in planning, induction and deployment of QKD systems. Further, integration of Service requirements with industry capabilities will bring in an appreciation for the real-world capability and scope of the technology, thereby enabling the Services to cut through the jargon and hype and approach the technology with a pragmatic understanding of its capabilities.

Conclusion

In conclusion, integration of Quantum Key Distribution (QKD) and Post-Quantum Cryptography (PQC) technologies into military communication networks is matter of strategic urgency, vital for the protection of these networks against the rising threat of quantum computers. QKD offers a fundamentally secure method for key distribution, leveraging the principles of quantum mechanics to enable the exchange of cryptographic keys with unconditional security guarantees. Meanwhile, PQC algorithms provide robust encryption mechanisms that are resistant to quantum attacks, ensuring the confidentiality and integrity of information transmitted over military networks.

Maintaining backward compatibility with existing encryption methodologies is crucial during this transition phase. It allows for integration of QKD and PQC technologies into current military infrastructures, ensuring interoperability and continuity of operations. This approach not only enhances the security posture against future quantum threats but also supports scalability by accommodating diverse operational requirements and technological advancements.

The induction of QKD kits is a laudable step in this direction. The real challenge, however, lies in enabling long-distance quantum key distribution using satellite links, an approach where nascent steps are being taken towards its development. In a quantum-computing world, the Indian Navy must continue to build on the foundation of QKD, engage with industry partners, ISRO and other government agencies to establish a secure communication network across our areas of operations.

Endnotes

  1. John Martinis and Sergio Boixio, “Quantum Supremacy Using a Programmable Superconducting Processor,” Google Research, October 23, 2019, https://research.google/blog/quantum-supremacy-using-a-programmable-superconducting-processor.

  2. P.W Shor, “Algorithms for Quantum Computation: Discrete Logarithms and Factoring,” Proceedings of the 35th Annual Symposium on Foundations of Computer Science (IEEE Santa Fe, NM, USA), https://ieeexplore.ieee.org/document/365700.

  3. Valerio Scarani et al., “The Security of Practical Quantum Key Distribution,” Reviews of Modern Physics, https://journals.aps.org/rmp/abstract/10.1103/RevModPhys.81.1301.

  4. D Stucki et al., “Long-term Performance of the SwissQuantum Quantum Key Distribution Network in a Field Environment,” New Journal of Physics 13, (2011), https://iopscience.iop.org/ article/10.1088/1367-2630/13/12/123001.

  5. M Peev et al., “The SECOQC Quantum Key Distribution Network in Vienna,” Journal of Physics 11 (2009), https://iopscience.iop.org/article/10.1088/1367-2630/11/7/075001.

  6. European Commission, “European Quantum Communication Infrastructure,” https://digital-stra tegy.ec.e uropa.eu /en/policies/european-quantum-communication-infrastructure.

  7. UK Quantum Communications Hub, “QKD Over 421 km of Ttandard Optical Fibre,” (2019), https://www.quantumcommshub.net/news/2019-12-19/qkd-over-421km-of-standard-optical-fibre.

  8. C. Elliott, “The DARPA Quantum Network,” Quantum Communications and Cryptography (2005), https://www.taylorfrancis.com/chapters/edit/10.1201/9781315221120-4/darpa-quantum-network-elliott.

  9. Richard J. Hughes, George L. Morgan, and C. Glen Peterson, “Quantum Key Distribution Over a 48 Km Optical Fibre Network,” Journal of Modern Optics 47, no. 2-3 (2000) https://www.tandfonline.com/doi/abs/10.1080/09500340008244058.

  10. US Dept of Energy, “Report on the Quantum Internet Blueprint Workshop,” QuantumWkshpRpt20FINAL_Nav_0.pdf.

  11. Sheng-Kai Liao et al., “Satellite-Relayed Intercontinental Quantum Network,” Physical Review Letters 120 ( 2018 ) , h t t ps:// j ournals. aps. org/ prl/ abstract/ 10 . 1103 / PhysRevLett.120.030501.

  12. Beijing-Shanghai Quantum Network, “Entanglement of two quantum memories via fibres over dozens of kilometres,” Nature, (2020), https://www.nature.com/articles/s41586-020-1976-7.

  13. “Rocketing ESA into the Future,” The European Space Agency, https://www.esa.int/ Enabling_Support/_for _the _Future/Discovery_and_Preparation.

  14. F Basso Basset et al , “Daylight Entanglement-Based Quantum Key Distribution with a Quantum Dot Source,” IOP Science, 8, no. 2https://iopscience.iop.org/article/10.1088/2058-9565/aaa0e9.

  15. “Cabinet Approves National Quantum Mission to Scale-Up Scientific & Industrial R&D for Quantum Technologies,” PIB Delhi, https://pib.gov.in/PressReleaseIframePage.aspx?PRID=1917888.

  16. Ministry of Communications, “C-DOT & PRL Demonstrate Integration of Indigenous Fiber Based Quantum Key Distribution System with Free Space QKD System Leading to End Quantum Communication Link in Both Fiber and Free space as Transport Medium,” PIB Delhi, https://pi b.gov.in/PressReleasePage.aspx?PRID=2011690.

  17. “QNu Labs Breaks the Distance Barrier in Quantum Key Distribution (QKD) Technology, Develops Commercially Ready New Variant of Armos QKD System,” Gadget Innovations, https://www.gadget-innovations.com/2022/06/qnu-labs-breaks-distance-barrier-in.html.

  18. Oishee Majumdar, “QNu Labs to Deliver Quantum Communication Systems to Indian Army,” Janes, https://www.janes.com/osint-insights/defence-news/defence/qnu-labs-to-deliver-quantum-communication-systems-to-indian-army.

  19. The Defence Space, "QNu Labs Signs Contract from Indian Navy for Quantum Key Distribution Systems," The Economic Times, https://economictimes.indiatimes.com/news/ defence/ qnu- l abs- bags- contract- f rom- indian- navy- for- quantum- encryption-systems/articleshow/100796060.cms?from=mdr.

  20. Sharddha Goled, "Indian Navy Partners with QNu Labs to Leverage Quantum-based Te c h n i q u e s f o r S e c u r e C o m m u n i c a t i o n , " Te c h C i r c l e , J u n 0 5 , 2 0 2 3 , https://www.techcircle.in/2023/06/05/indi an-navy-partners-with-qnu-labs-to-leverage-quantum-based-techniques-for-secure-communication.

  21. “QNu Labs Secures: Landmark Contract with Indian Navy for Quantum Encryption Systems,” Business Standard, https://www.business-standard.com/content/press-releases-ani/qnu-labs-secures- landmark- contract- with- indian- navy- for- quantum- encryption- systems-123060700744_1.html

  22. Department of Space, ISRO Makes Breakthrough Demonstration of Free-Space Quantum K e y D i s t r i b u t i o n ( Q K D ) O v e r 3 0 0 m , ” I SRO , h t t p s : / / w w w. i s r o . g o v. i n / Quantum%20Key%20Distributio n%20(QKD).html.

  23. “IN-SPACe Inks Pact with QNu Labs to Develop Satellite Quantum Key Distribution Products,” The Economic Times, https://economictimes.indiatimes.com/news/science/in-space-i n k s - p a c t - w i t h - q n u - l a b s - t o - d e v e l o p - s a t e l l i t e - q u a n t u m - k e y - d i s t r i b u t i o n - products/articleshow/96368515.cms?from=mdr.

  24. Ministry of Defence, “Indian Army Establishes Quantum Laboratory at Mhow (MP),” PIB Delhi, https://pib.gov.in/PressReleasePage.aspx?PRID=1786012.