Telefónica, Huawei, and UPM (Universidad Politécnica de Madrid) have conducted a field trial demonstrating the application of quantum cryptography on commercial optical networks, and integrating the technologies operationally using SDN.
All secure communications are based on the use of cryptography. Current cryptographic techniques for key generation are based on highly complex mathematical problem, that require long calculations to be resolved. As computational capacity grows, the time required to solve these problems becomes shorter, reducing the security of the keys.
The continuous growth in computational capacity has required a steady increase in key sizes and the complexity of key generation algorithms. And these techniques can become completely futile with the advent of quantum computers, able to apply the principles of quantum mechanics to resolve problems currently considered unsolvable, including breaking the keys used by current methods, thus rendering most of the existing security infrastructure useless.
Quantum technologies themselves provide a solution to this vulnerability. Quantum principles can be applied to exchange a key between the two ends of a communications link, so that this key remains secure with respect to any attack, and any attack attempt becomes detectable. This technique, known as quantum key distribution (QKD), not only provides protection against the threat posed by quantum computation to current cryptographic algorithms, but it can also provide a much higher security level for any exchange of data. However, QKD requires a high-quality optical fiber physical infrastructure.
Telefónica, Huawei, and UPM say they have been working to develop a field trial that demonstrates the provision of secure communication services based on QKD using a commercial SDN-managed optical network infrastructure”.
“Telefónica Spain’s optical network, in combination with our high-capacity photonic transmission systems, offer the required performance to provide secure channels based on quantum communication,” said María Antonia Crespo, director of transport and IP connectivity at Telefónica Spain. “This enhanced security is a key enabler for next generation networks, flexible, virtualized and software-defined.”
Quantum cryptography you can use
Up to now, QKD feasibility was demonstrated in laboratories and restricted field trials (such as one that Telefónica and UPM performed back in 2009, demonstrating quantum key exchange over a fiber metro ring). The actual deployment on commercial infrastructures and integration with their operational procedures has remained a significant challenge.
The field trial – which involved installation of the solution in production facilities using standard telecoms systems– is a first of its kind demonstration, which shows the capacity of the technology to reach real-world level of usability, said Vicente Martin, head of the Center for Computational Simulation, who also leads the team at UPM.
“The ability to use new network technologies like SDN, designed to increase the flexibility of the network, together with new QKD technology is what allows us to really converge quantum and classical networks on the existing optical fiber infrastructure, Martin said. “Now we have, for the first time, the capability to deploy quantum communications in an incremental way, avoiding large upfront costs, and using the same infrastructure.”
The field trial relies on “continuous variables” (CV) QKD technology. A particular feature of the tested devices is that they are flexible, software-controlled ones. The systems are optimally adapted to a seamless integration in the dynamical environment of SDN and NFV networks, where the creation and modification of the optical fiber paths – and required encryption – follows commands received over software-based control interfaces. The latter functionality is ensured by integrating the CV-QKD devices with standard optical transport network ones.
The full scale QKD + SDN/NFV integration opens the way of providing high level security of novel flexible but critical infrastructures, said Momtchil Peev, Huawei project leader of the Quantum Communication Project in Munich.
“The test CV-QKD devices that we present here have the inherent CV advantages – they do not need ultra low-temperature, bulky single photon avalanche detectors, and can potentially reuse classical optical coherent communication technology, Peev explained. “Moreover instead of addressing performance records alone we have chosen a flexible design focusing on control and key delivery interfaces, showing the feasibility of more seamless future integration into modern networks.”
The field trial uses he optical infrastructure provided by Telefónica Spain, connecting three different sites within the Madrid metropolitan area where software-controlled CV-QKD devices (developed by the Huawei Research Lab in Munich in collaboration with UPM) are installed, together with SDN-based management modules developed by Telefónica’s GCTIO Network Innovation team, and the components required to integrate QKD with NFV and SDN technologies developed by UPM.