Physicists at Toshiba have used quantum cryptography to transmit voice and video data over a secure optical-fibre link. The demonstration is significant because it shows that the single-photon encryption technology is compatible with real Internet Protocol (IP) traffic and is also robust enough for deployment on commercial optical-fibre networks. The system was shown to financial institutions at the Department of Trade and Industry in London by Andrew Shields and colleagues from Toshiba Research Europe at the end of April.
Physicists at Toshiba have used quantum cryptography to transmit voice and video data over a secure optical-fibre link. The demonstration is significant because it shows that the single-photon encryption technology is compatible with real Internet Protocol (IP) traffic and is also robust enough for deployment on commercial optical-fibre networks. The system was shown to financial institutions at the Department of Trade and Industry in London by Andrew Shields and colleagues from Toshiba Research Europe at the end of April.
Quantum key distribution (QKD) provides an attractive means for securing communications in optical fibre networks. However, deployment of the technology has been hampered by the frequent need for dedicated dark fibres to segregate the very weak quantum signals from conventional traffic. Up until now the coexistence of QKD with data has been limited to bandwidths that are orders of magnitude below those commonly employed in fibre optic communication networks. Using an optimised wavelength divisional multiplexing scheme, we transport QKD and the prevalent 100 Gb/s data format in the forward direction over the same fibre for the first time. We show a full quantum encryption system operating with a bandwidth of 200 Gb/s over a 100 km fibre. Exploring the ultimate limits of the technology by experimental measurements of the Raman noise, we demonstrate it is feasible to combine QKD with 10 Tb/s of data over a 50 km link. These results suggest it will be possible to integrate QKD and other quantum photonic technologies into high bandwidth data communication infrastructures, thereby allowing their widespread deployment.
Quantum key distribution (QKD) provides an attractive means for securing communications in optical fibre networks. However, deployment of the technology has been hampered by the frequent need for dedicated dark fibres to segregate the very weak quantum signals from conventional traffic. Up until now the coexistence of QKD with data has been limited to bandwidths that are orders of magnitude below those commonly employed in fibre optic communication networks. Using an optimised wavelength divisional multiplexing scheme, we transport QKD and the prevalent 100 Gb/s data format in the forward direction over the same fibre for the first time. We show a full quantum encryption system operating with a bandwidth of 200 Gb/s over a 100 km fibre. Exploring the ultimate limits of the technology by experimental measurements of the Raman noise, we demonstrate it is feasible to combine QKD with 10 Tb/s of data over a 50 km link. These results suggest it will be possible to integrate QKD and other quantum photonic technologies into high bandwidth data communication infrastructures, thereby allowing their widespread deployment.
Abstract The fundamental concepts of quantum cryptography were developed in the 1980s and the first experimental proof of principle was given in 1992. Since then, the subject has developed to the point where demonstration systems have been installed that run over long distances down standard telecommunication optical fibre systems. This rapid growth of research activity is partly fuelled by the curiosity of scientists, and partly by the fears of military, government, and financial institutions about data confidentiality and computer security.
Quantum cryptography has been proven to be the only practical method for fast distribution of secret keys needed for encryption. It enables absolutely secure information transfer from one party to another and allows for the detection of an eavesdropper without sacrificing security. This project involved designing and building a quantum cryptography device. This device has applications in many fields, including internet security as well as military communications. The data are encoded on single photons, which are sent through free space over a distance of about 30 cm. The electronics, which control the device however, are equally suitable for operation with fibre optic cables. The device was designed to operate in dark conditions within a laboratory. Currently, no research group has demonstrated transmission speeds faster than 8 kb/s. The aim of this project was to achieve bit rates faster than 10 kb/s, while operating under strict economic constraints. Although quantum cryptography was not demonstrated in the laboratory due to problems with the detector, the emission end, which generates single photons of light with one of two different polarisations, was shown to work as it was designed. The current design has limited commercial future due to the dark conditions under which the communication must take place. The project however has demonstrated that quantum cryptography is getting closer to becoming a reality.
Quantum mechanics is playing an important role in the security of encrypted messages through quantum cryptography. Cryptography is an important part of the computer and communication networks that protects data in many fields such as business e-mails, bank transactions, and Internet shopping. The information is kept secret using a mathematical formula called as encryption algorithm, with a secret key that the sender uses to scrabble a message in such form that is not understood by anyone other, the recipient then uses the same key in the form of along binary number with a detection algorithm to read the message. The secure bit rate decreases with the rate of the optical link due to scattering of the photons from the fiber, and the best performance is achieved by with a wavelength of 1.55μm at which the standard optical fiber is transparent. Companies are using the high width optical connections between the offices, data centers, server farms, and disaster recovery sites for safety.
Quantum cryptography has transitioned from laboratory demonstrations to commercial deployments across five continents. This chapter provides a comprehensive overview of the commercial quantum cryptography landscape, covering market dynamics, technology approaches, key industry players, real-world deployment case studies, evolving standards and regulation, and future outlook. We profile four representative industry leaders – ID Quantique, Toshiba, Quantinuum, and QuintessenceLabs – spanning distinct strategies from fiber QKD and satellite QKD to quantum-enhanced key generation and QRNG-focused key management. Major deployments including SwissQuantum, Tokyo QKD Network, Beijing–Shanghai Backbone, UK Quantum Network, and EuroQCI illustrate the progression from trusted-node metro networks toward hybrid fiber-satellite architectures. Standards from ETSI, ITU-T, ISO/IEC, NIST, BSI, and ANSSI are maturing, enabling interoperability and certification. The convergence of QKD, QRNG, and post-quantum cryptography (PQC) into hybrid quantum-safe solutions represents the dominant commercial trajectory, driven by government mandates (NSM-10, EuroQCI, India’s National Quantum Mission) and the impending PQC migration. Key challenges remain: distance limits without quantum repeaters, cost reduction via photonic integration, multi-vendor interoperability, and business model evolution toward key-as-a-service. The next decade will see satellite QKD constellations, quantum repeater prototypes, and converged quantum-classical network management at scale.