Quo Vadis Qubit? Security in the quantum computing era.
I was on my way out of the rather impressive IBM Watson IoT Tower in Munich. Still a bit puzzled, rushing to the subway, I was struggling to fathom the overwhelming amount of information presented a few hours ago by leading scientists around the world at a conference held in the IoT tower. Why did I care in the first place? And what does a security researcher have to do with superpositions and entanglements? Well, there appeared to be a good reason for that and maybe I should begin to worry about my very own field of research!
The hype around quantum technology is huge - no doubt about that - but where does this “awesomeness” stem from? There is a rather superficial analogy used frequently to explain how quantum computing (QC) works and why it promises such huge speed-ups in computations. Albeit not accurate, I’m reusing it here for simplicity. In conventional computers, bits can store either a binary value of ‘1’ or ‘0’, whereas qubits (the quantum analogous of bits) may exist in a combination (superposition) of states ‘0’ and ‘1’ at the same time. During a quantum computing calculation, typically following a quantum algorithm, qubits may exist in any of the exponential number of superpositions of these ‘1’ or ‘0’ states. This ability of QC to account for any of the number of superpositions at any moment is what generates, with a pinch of vagueness, those huge computational speed-ups.
So, the million-dollar question remains: why should the security community care about QC? There are a lot of misconceptions around QC, at least for the non-experts. QC is an amazing technology and will surely change the way we think about problems and the way we compute. However, for the time being, only a handful of problems can be solved using algorithms that harness the power of quantum computation. It just happens that we were so unlucky that some of those problems constitute the basis of current public-key cryptography; hence everything we take for granted today as secure will be in jeopardy if a large enough quantum computer hits the headlines in a few years’ time.
In our current paper, we review the bits and bytes of QC to offer an easy-going yet comprehensive overview of quantum mechanics and to shape a clear view of its capabilities and its current status. Ongoing research initiatives have produced some remarkable quantum machines, which, although they are not yet able to crack your encryption, they certainly raise awareness around crypto-research. Since the common assumptions on cryptography do not apply to quantum technologies, we investigated the alternatives. In the past few years, a small yet dedicated community of cryptologists, mathematicians, and engineers have produced a remarkable pool of crypto-algorithms which are considered to be safe under quantum cryptanalysis. They are the so-called “quantum-safe” or “post-quantum” crypto-algorithms.
Just because we face a lot of obstacles in realizing a large enough quantum computer, it doesn’t mean that we have the luxury of time in developing and testing quantum-safe algorithms. Think of all the vulnerabilities and crypto-failures happening today for algorithms that have been out there for decades and then you should realize why we should care now about security in the quantum world. It appears though, that research is on a very good track - some of those algorithms have seen the light of standards and they are even part of popular browser suites.
Without revealing anything more, you can read about the mechanics, challenges, security implications, and future of QC (along with some chess problems for the avid player – sorry, no hints given) in our article published in the Bell Labs Technical Journal at IEEE