Paving the Way Towards 800 Gbps Quantum-Secured Optical Channel Deployments in Mission-Critical, Real-World Environments

Since its inception almost four decades ago, quantum cryptography has matured into a well-developed, practical field of research. In parallel, the development of cryptographically relevant quantum computers on the horizon threatens the security of today's asymmetric cryptographic systems, and therefore the security of today's information infrastructure. While so-called "post-quantum" public key schemes may prove to be sufficient for many applications, they necessarily rely on certain complexity theoretic assumptions, leaving open the possibility that future advances in complexity theory could break these systems. Quantum key distribution, by contrast, can be used to achieve information theoretic, unconditional security by relying on the principles of quantum mechanics in place of computational assumptions, making it an attractive, future-proof option for high-risk sensitive communications. In this work, we demonstrate the validity of quantum key distribution at industry scale. We report on the successful deployment of QKD devices into a replica environment of JPMorgan Chase's Data Center Interconnect network. The QKD links were established, to our knowledge for the first time, over a single fiber with multiple high capacity Dense Wavelength Division Multiplexed (DWDM) channels. These high capacity channels included an 800 Gbps quantum-secured channel carrying data encrypted by the symmetric keys generated by the system, as well as 1.6 Tbps of additional traffic. This high capacity link was established at distances up to 100 km while maintaining secret key rates that could supply 258 separate AES-256-GCM encrypted channels with a key refresh rate of 1/sec. In real-world deployments, the ability to use a single fiber to establish the quantum channel and the DWDM channels is of the utmost importance as dark fiber is a valuable commodity. Of course, there are complications inherent in multiplexing the fragile quantum signal with high-capacity DWDM channels. In our work, we quantify the impact of these complications, as well as a number of realistic factors inherent to real-world deployments. Finally, we compare and contrast the results we achieve with previous works investigating real-world and multiplexed deployments of QKD, as well as theoretical results in those areas.