Quantum Key Distribution (QKD) and the
Role of Optical Circuit Switching in Secure Networking
In this Blog Post, Rohit Kunjappa, Head of Product Management & Application Engineering at
HUBER+SUHNER Polatis, explains the role of and need for optical circuit switching in secure networking.
In an increasingly interconnected world, data security has become paramount. Traditional encryption
methods, while robust, face threats from ever-evolving quantum computing capabilities. This is where
Quantum Key Distribution (QKD) comes into play. QKD is a cutting-edge technology that leverages the
principles of quantum mechanics to secure communication channels. In this blog, we will provide an
overview of QKD and explore how optical circuit switching can enable the deployment of secure QKD
Understanding Quantum Key Distribution (QKD)
QKD is a cryptographic technique that harnesses the fundamental principles of quantum mechanics to
create secure communication channels. It relies on the properties of quantum entanglement
Heisenberg Uncertainty Principle
to generate encryption keys that are practically unbreakable. Here is a
breakdown of how QKD works:
- Quantum Key Generation: QKD systems use a source of quantum particles, typically photons, to
transmit information. These particles are encoded with quantum states, such as polarizations,
that represent 0’s and 1’s in binary code.
- Transmission: The quantum particles are then sent over a communication channel to the
recipient. Any attempt to eavesdrop on the transmission will inevitably disturb the quantum
states, alerting both parties to the intrusion.
- Key Comparison: The sender and receiver compare a subset of the quantum states they
received to check for any discrepancies caused by potential eavesdropping. If the channel is
secure, they proceed to distill a shared secret key.
- Secure Communication: With the shared secret key in hand, the sender and receiver can use it
for secure communication, such as encrypting and decrypting data.
QKD offers the promise of "future-proof" security, as even the most advanced quantum computers
would struggle to crack the encryption generated through this method between key updates. One
important factor to consider here is that the cryptographic keys communicated through the quantum
channels should be updated as frequently as possible. The rate at which this can be performed is
dependent on the capabilities of the QKD transmitters (often referred to as “Alices”) and receivers
(“Bobs”) and the quality of the optical fiber links between them.
However, deploying QKD at scale in a network requires careful consideration of the underlying
The Role of Optical Circuit Switching
To realize the full potential of QKD for secure networking, we need a robust and flexible network
infrastructure. Optical circuit switching (OCS) can play a vital role in this context. OCS is a technology
that enables the dynamic allocation of optical resources, allowing for efficient and secure data
Here's how OCS can enhance QKD networking:
- Resource Allocation: OCS allows for on-the-fly allocation of dedicated optical circuits for QKD
communication. This ensures that quantum keys are transmitted over a secure, interference-
free channel, minimizing the risk of eavesdropping.
- Low Latency: OCS offers low-latency switching, which is crucial for QKD. The speed at which
quantum keys are exchanged and verified is critical for maintaining secure communication.
- Scalability: As QKD networks grow, OCS can adapt to the changing demands by reallocating
optical circuits as needed. This scalability ensures that QKD can be seamlessly integrated into
existing and future network architectures.
- Diverse Applications: Beyond QKD, OCS can also support other secure communication
technologies, such as traditional encryption methods and data center interconnects, making it a
versatile tool for network security.
Quantum Key Distribution holds immense promise for securing communications in the age of quantum
computing. However, to fully leverage the potential of QKD, a robust network infrastructure is essential.
Optical circuit switching provides the flexibility, speed and security required to enable a seamless QKD
See our related blog on OCS for Quantum Networking: quantum networking
If you would like to know more about POLATIS optical circuit switches and how the technology would
benefit your QKD application, you can contact us by email or phone:
+1 781 275 5080
EMEA/Rest of World:
+44 (0)1223 424200