Quantum Communications for Security and Quantum Computing
5. QKD has an increased risk of denial of service. At its most basic, the essence of QKD is that it senses an intrusion and will deny and stop service when an intrusion is detected. However, today’ s QKD technology enables keys to be redirected at such a speed that there is virtually no performance impact.
In brief, the combination of QKD plus PQC will provide an unprecedented level of defense [ 10 ] against data breaches today [ 11 ], protecting even data harvested during a criminal attack. You can protect data against theft now and create a safe communications conduit that will withstand even the advent of a quantum computer. It is very concerning that our government security experts are rolling the dice that our adversaries may some day break the math-based PQC algorithms. Going into a quantum security battle with one weapon is shortsighted at best and potentially disastrous at worst if we can no longer secure our sensitive information.
3 IS QKD THE BRIDGE TO PRACTICAL QUANTUM COMPUTING
While tech industry leaders like Nvidia CEO Jensen Huang and Meta CEO Mark Zuckerberg are predicting the availability a practical quantum computer anywhere from 15-30 years away [ 12 ], quantum communications can represent an opportunity to reach a cryptographically relevant quantum computer( CRQC) much, much sooner. A CRQC is akin to reaching the promised land of quantum computing because it has a large enough number of qubits to break current public-key cryptography— the most readily used encryption for most communications [ 13 ]. There are challenges to achieving a CRQC— current quantum computers lack stability and error correction, they are subject to distortion from external, environmental impacts that lead to decoherence, and they are prohibitively expensive to build and scale.
Yet there are approaches supported by technologies like QKD in which qubits are transmitted from one quantum computer to a second computer’ s quantum processing unit( QPU), thereby increasing the networked computers now with the sum of both computers number of qubits. This distributed or networked quantum computing could be just a few years away.
These include:
1. Satellite-based QKD [ 14 ] [ 15 ]. Fiber optic cable is a limiting factor for QKD and quantum communications. Most single-mode fiber loses 0.2db per kilometer, limiting the effective distance for quantum communications and QKD to approximately 150 kilometers. But all is not lost. While the physical properties of quantum signals may not be cloned and amplified, there exist quantum techniques to increase the distances that may be achieved with QKD and quantum communications [ 16 ]. QKD on satellites relies on the fact that the vacuum of outer space has little to no associated attenuation. A QKD-equipped satellite in low Earth orbit( LEO), 2,000 kilometers above the surface of the Earth, will only experience signal attenuation for the last 10 kilometers of the transmission through the Earth’ s atmosphere.
124 May 2025