Quantum Key Distribution (QKD) vs. Post-Quantum Cryptography (PQC) – by Rupert Ursin

Quantum Key Distribution (QKD) vs. Post-Quantum Cryptography (PQC) – they both have their right to exist! 

Even a new kind of software-based cryptography, such as Post-Quantum Cryptography (PQC), does not solve the problem, as it (again!) relies on assumptions about the hacker. Physics-based Quantum Key Distribution (QKD) does not! 

With the looming threat of quantum computers, the need for robust encryption methods in our digital age has never been more critical. So let's dive into the significance of QKD and why PQC might not be the golden bullet we hope for:

Traditional encryption methods, such as RSA, rely on mathematical hardness, making them vulnerable to quantum attacks once the first large-scale quantum computer becomes a reality. PQC, while promising, still hinges on assumptions about the resources available to potential hackers, much like RSA. 

Not every device can host full-fledged QKD protocols, especially on a consumer scale, like your everyday smartphone does. Hence, the adoption of PQC is inevitable, as it will serve as a necessary backup to current encryption methods. PQC is important for the end-user!  

Where QKD truly shines is in securing backbone channels and critical communication infrastructures, where a quantum computer-backed hacker can cause maximum damage with a small intrusion. QKD’s reliance on the fundamental principles of quantum mechanics makes it incredibly resilient to all possible quantum attacks – without making any assumptions about the hacker or his or her computational power. On the other hand, it is impossible to scientifically postulate that a quantum computers  cannot break PQC. But the very laws of nature guarantee that noone ever will be able to overcome QKD!

As with all mathematically based encryption methods, security is based on the unproven assumption that, despite all the efforts of the cryptographic community, no algorithm is generally known with which these encryptions could be broken.  

In the quantum era, physical security through QKD will play an indispensable role in safeguarding highly sensitive data. The day is near when quantum computers will be capable of compromising even the most advanced encryption methods, making the need for truly quantum-resistant solutions like QKD all the more evident.

As we move forward into this uncertain quantum future, it is crucial for organizations and individuals to stay informed, adapt, and invest in quantum-safe encryption methods like QKD, especially for our most critical communication channels and data. The race to secure our digital world continues, and QKD is poised to be at the forefront of this quantum revolution.