If Murphy’s Law holds that everything gets worse, Moore’s Law has long been the opposite, at least when it comes to computing.

Named for Intel co-founder Gordon Moore, it states that the number of transistors that will fit on a chip doubles roughly every 18 months, which explains why our gadgets keep getting better, stronger, faster, smaller.

Unfortunately, in as little as 10 to 15 years, this relentless process will crash into the limits of physical possibility, as transistors shrink to atomic proportions.

Enter quantum computers, which don’t yet exist in practical form, but promise an expanded and vastly more powerful computing environment.

Quantum computers will be able to break many of the cryptographic locks we use to protect data today, but quantum technologies also mean we will be able to build new locks that can’t be picked, not even by a quantum computer.

As concerns mount around online privacy and data security, scientists in Waterloo have been immersed in world-leading cryptographic research to prepare us for the quantum future.

Communitech caught up with Michele Mosca, deputy director of the Institute for Quantum Computing at the University of Waterloo, to talk about quantum cryptography and its implications for online privacy and security.

Mosca, also a founding member of Waterloo’s Perimeter Institute for Theoretical Physics, was a driving force behind IQC’s creation in 2002, along with Research In Motion co-CEO Mike Lazaridis and PI’s then-executive director, Howard Burton.

IQC’s faculty of 17, set to expand to 30 in the coming years, are building on decades of Waterloo expertise and inspiration, including that of late professor Bill Tutte. His code-breaking exploits for Britain, largely unsung, gave the world its first electronic computer and changed the course of the Second World War.

UW is also home to the Centre for Applied Cryptographic Research, where Mosca is an affiliate faculty member.

Mosca, who describes Waterloo’s quantum research as “second to none,” says no one can be sure when a quantum computer will arrive, so it’s critical to prepare now to ensure our secrets will be safe in the future.

Q – What is cryptography?

A – Cryptography refers to the basic mathematical tools we use to try and provide information security.

We often think of it in terms of privacy, but it’s broader than that. We also want data integrity. I might get a message and I might know it’s secret, but how do I know no one has changed it? So I want data integrity, and I also want to know it came from you and not someone else.

Cryptography is the use of mathematical tools to achieve those objectives.

There are also physical tools; you could lock information in a safe and carry that safe around, but cryptography is a way that you can mathematically scramble it, or have a mathematical access structure to it.

Q – So you’re turning it into a code that hopefully can’t be broken?

A – Right.

Q – How does quantum cryptography differ from classical cryptography?

A – There are generally two types of classical cryptography.

There are codes that are computationally secure, where you hope you can’t break the code but you don’t really know for sure; then there are others, which are information-theoretically secure, where we know that there just is not enough information to break the code.

We generally use computationally secure crypto because it’s more efficient and you can do more things with it. The number of things we can do with information-theoretic security is more limited, and usually requires more resources.

So what’s quantum cryptography? It’s a vague term, but the broadest definition is, it’s crypotography in a quantum world. So, you have to take into account the potential existence of quantum computers.

Computational security is based on some mathematical problem being hard, on a computer. But now, we have to reassess what’s hard and what’s easy, taking into account quantum computers.

Almost all of the currently used public-key cryptography relies on either factoring being hard, or this elliptic-curve problem being hard. Quantum computers can break both of those problems, so most of the currently-used public-key cryptography would be broken if and when we have a quantum computer.

So, we need to find and deploy alternatives that are secure against quantum computers.

Q – Is that because a quantum computer could come into existence sooner than we think?

A – We don’t know. If you ask any of the experts in the field who are trying to build one, they’ll say it’s not going to happen any time soon; we just don’t know. That’s the correct answer.

But, as with any fundamentally new or disruptive technology, you’re not going to get a big lead time. They’re going to go from not knowing how, to ‘Oh, here it is.’ Once you have it, you can start making predictions that are pretty reliable, but it’s the breakthrough stuff that no one’s able to predict.

Now, if you go and ask the experts, ‘Are you going to build a quantum computer in the next five to 10 years,’ they’ll say no. But in the big picture, hundreds of the world’s smartest experimentalists and theorists are working on this, and they’re all making progress.

So, I’m optimistic that it’s going to happen, but it’s one of these intrinsically unpredictable things, and there’s no reason to expect to get a long heads-up. There’ll be a pretty fast eureka moment, and we’ll have the first-generation quantum computers shortly thereafter.

Q –So we need to be ready, because when that happens, people will be able to break the security codes that are out there now?

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