高清福利片

What if the simple act of tapping your card could put your identity at risk?

Every day, we trust encryption to protect our money, data, and digital lives. But quantum computers are advancing fast,聽and soon they could crack today鈥檚 security in seconds, making our current 鈥渄igital locks鈥� obsolete.

So how do we protect ourselves in a quantum world?

On this episode of聽The Solutionists, host聽Mark Scott聽explores the race to reinvent cybersecurity for the quantum age.

He speaks with leading mathematician Nalini Joshi, 2025 NSW Scientist of the Year,聽who鈥檚聽bringing together some of the world鈥檚 brightest minds to develop new forms of encryption powerful enough to withstand quantum computing. She explains why maths is central to our digital聽future, and聽how mathematical thinking can unlock entirely new possibilities.

Plus, PhD researcher Prachi takes us inside a quantum control lab for a rare glimpse of a quantum computer in action.

惭补谤办听厂肠辞迟迟听听00:01

This podcast is recorded at the University of Sydney's Camperdown campus on the land of the Gadigal people of the Eora nation.聽They've聽been discovering and sharing knowledge here for 10s of 1000s of years. I pay my respects to elders past and聽present, and聽extend that respect to all Aboriginal and Torres Strait Islander people.

笔谤补肠丑颈听听00:33

Hi,聽I'm聽Prachi.聽I'm聽a PhD student here at the聽Quantum聽Control聽Lab, and here in this lab, we聽do very聽many things. One of the things that we do is trapped ion quantum computing, where we use trapped ions, control them with microwaves and lasers to聽sort of interact聽with them and do quantum stuff with them.聽I'm聽going to take you on a little tour of the quantum control lab. Hey, welcome!聽That's聽the sound of the sliding doors opening, which聽we聽keep them聽closed to聽maintain聽the pressure around the lab, because the equipment in the lab, especially the trapped ions,聽are聽very sensitive聽to pressure changes. So,聽we've聽got the lab split on聽a very special聽place, in the sense that聽it's聽covered by聽these solid cage-like聽system. And on the ground below, there is a聽big cemented聽block, and聽that's聽to make the mechanical movement of the floor very, very stable, so that nothing shakes on the scale of an atom or ion.聽This is聽a very, very common聽sound that聽you'll聽hear in quantum labs all around. The聽pulsing聽or the heartbeat sound that聽you're聽hearing is from a cryogenic pulse聽tube-based聽compressor here, which is a cooling unit聽on in聽itself. What聽it's聽doing is trying to cool something down to minus 200 degrees.聽Yeah, so聽that's聽very close聽to absolute zero, and聽that's聽something we need to聽maintain聽the accuracy of a聽clock-based聽system that we use.

惭补谤办听厂肠辞迟迟听听02:38

The digital聽world聽as we聽know it聽is at risk, a scary thought, given just how entangled it is with our physical world now. Our daily lives now rely on a network of cyber security systems, and聽all of聽these systems are under threat as we near the quantum era. In the future, quantum computers will be powerful enough to break any digital lock that exists right now. The solution:聽quantum聽proof聽encryption. The next problem is that this kind of encryption will require mathematics so complex that almost nobody in the world understands it right now. Now, if your head's spinning just because I said the word聽quantum, stick with me, because I need to introduce you to Professor Nalini Joshi, the 2025 New South Wales聽Scientist of the聽Year. Nalini is the first mathematician to win that prize, and聽she's聽the chair of applied mathematics here at the University of Sydney. And right聽now,聽she's聽leading a team of Australia's top聽maths聽minds in a furious effort to prepare us for our quantum future. Nalini, welcome. Paint us a picture of the future that聽you're聽worried about. What does life look like if quantum computers can break our current cybersecurity systems?

狈补濒颈苍颈听闯辞蝉丑颈听听03:59

So聽quantum computing comes with the promise of great achievements, and at the same time, great dangers.聽You've聽just outlined some of those dangers, but I also want to emphasise that it comes with聽a huge number聽of positive聽potential. The power of quantum computing will give us new materials, new medicines, new sustainable solutions. As you know, governments around the world, including ours, have been investing聽huge amounts聽into it for at least the last 10 years, and Australia in particular, is going to be spending a billion dollars building a quantum computer somewhere near Brisbane airport, I believe. But the counterpart to that story is that that same power will allow them to factor聽very, very large聽numbers, and聽that's聽where the problem lies for our current security systems. So, if you think about how we buy things online; we enter our name, our credit card details, each of those things that we enter get converted to a number. The security, the secret wall that surrounds that information, is built out of our inability to factor聽very large聽numbers on our current computers.聽So聽when the secrets have been turned into numbers, and these are聽very large聽numbers now, 4096 binary digits.聽That's聽a huge number聽we are trying to grapple with.聽First of all, transmitting those聽huge numbers聽to our banks or other people, and then for a hacker to be able to work out what that message is,聽they'd聽have to factor that聽very large聽number. And on our current computers, that will take more than our lifetimes.

惭补谤办听厂肠辞迟迟听听06:09

Right. So, I might want to crack your credit card number, but using my current computers and current processing powers,聽that's聽going to take me my lifetime. So, what does quantum computing then do to make it more聽viable聽if I wanted to聽be able to crack that code?

狈补濒颈苍颈听闯辞蝉丑颈听听06:28

So聽there is an algorithm on quantum computers.聽It's聽been known for more than 30 years now, called after the man who discovered it and invented it, Peter Shaw. His algorithm gives us a way to factor large numbers on a quantum computer in a way that we聽can't聽on a classical computer. And,聽when that runs on a quantum computer with sufficiently many fundamental bits, or qubits, they call it, then it will be able to factor them in a day or two, or even聽minutes, once聽they get聽more and more聽powerful.

惭补谤办听厂肠辞迟迟听听07:06

So,聽somebody who was trying to crack the code with the power of quantum computing could be able to do that in聽a very short聽period of time,聽almost an聽immediate聽period of time.

狈补濒颈苍颈听闯辞蝉丑颈听听07:19

That's聽right,聽that's聽right.聽In the time it takes you to tap your card on your聽eftpos聽machine, and it gets transmitted to the next step in the Internet era. It will be listened to, held,聽and cracked within a few minutes.

惭补谤办听厂肠辞迟迟听听07:37

This is disturbing stuff; our entire world is built on the security systems around non-quantum computing. As聽you've聽said, quantum computing has been coming for a while, but聽it's聽a global focus here at the University of Sydney and in the city of Sydney. We聽have a lot of work underway on quantum.聽How far in the future are we talking about? How sci-fi is this kind of breakthrough that could see this threat to our cybersecurity infrastructure?

狈补濒颈苍颈听闯辞蝉丑颈听听08:07

So,聽the answer depends on who you believe about the prospect of having a workable quantum computer with that many qubits. Some people say聽it's聽5聽years, some people say 10,聽maybe even聽20. But accompanying that hardware promise is also a software development:聽things are getting more and more accurate in terms of what we can do with quantum computers, and that effort has made the number of estimated qubits that you need on a quantum computer smaller and smaller to be able to do this cracking.聽So聽in other words,聽we've聽got two counterparts:聽the hardware and the software side, and聽they're聽both going in the same direction.聽So聽I personally think it could be within 10聽years time.

惭补谤办听厂肠辞迟迟听听09:01

If we think of ourselves as individual citizens and consumers, what can we realistically聽anticipate聽will change?聽We once used to remember passwords, now聽it's聽multi-factor authentication. What do you think the security world might look like for us in this new era that聽you're聽anticipating?

狈补濒颈苍颈听闯辞蝉丑颈听听09:23

It's聽hard to know, but I think聽it'll聽be like MFA, multi-factor authentication on steroids.聽We'll聽have to know a lot more about how we are pursuing,聽how聽we're聽using devices, how聽we're聽logging into things,聽whether or not聽the systems聽we're聽using have this extra protection or not. So right now, many companies are adopting the proposed harder algorithms to protect us from that future, but not everyone.聽And in particular, not聽every company knows what to do with this聽issue, even though the Australian聽Signals Directorate聽has recommended that we transition over to them by 2030.

惭补谤办听厂肠辞迟迟听听10:08

So,聽let's聽talk a little bit more about the work that聽you're聽doing to聽anticipate, you know, our readiness for these kinds of challenges. If the digital infrastructure that聽we've聽currently built, the security around that is going to be seriously threatened, how are we going to lock up things in the quantum world? What might quantum security look like in the future?

狈补濒颈苍颈听闯辞蝉丑颈听听10:32

So聽there's聽two parts to that story as well. So first of all, we have to protect the data that we are currently producing now, because, you know, my date of birth isn't going to change in 10聽years time, my passport number may not change by then, depending on how old your passport is.聽So,聽with people already being hacked for this kind of personal data, and that information being collected,聽that needs to have a wall around it so that future quantum computers聽can't聽break that protocol. So that part is, I think,聽fairly clear, but what聽we're聽doing is creating new algorithms to make it harder and longer for numbers to be factored. But聽there's聽also the other part, the quantum computing side. You need algorithms that will work on quantum computers to protect our data when聽we're聽using quantum computers in the future. And聽that's聽a totally different聽beast that has several pathways in it.聽It's聽actually a聽fascinating direction of research, but I think again, there is a competition between the hardware and the software sides of things.

惭补谤办听厂肠辞迟迟听听11:54

I'm聽wondering why we聽haven't聽been talking about this more.聽Yilei聽Chen, the cryptographer, published work聽which I think in academic circles聽generated quite a lot of attention, saying that quantum computers will be able to attack certain聽very strong聽security algorithms, that聽there'd聽been a level of confidence about.聽A聽lot of reaction to that amongst researchers, but in the broader public,聽probably no聽visibility at all. But this聽is,we聽talk a lot about cyber security, why isn't this聽kind of far聽bigger threat generating more attention聽do you think?

狈补濒颈苍颈听闯辞蝉丑颈听听12:29

So, can I be impolite?聽

惭补谤办听厂肠辞迟迟听听12:33

Go right ahead.

狈补濒颈苍颈听闯辞蝉丑颈听听12:35

So,聽I think聽probably the聽excitement around quantum computers has been so much around building the hardware, making the results of that聽somewhat reliable, making the error correction work, that聽we've聽all gone with that flow of excitement.聽We've聽all said,聽鈥渙h, this is going to be like, you know, the future world.聽We're聽going to be able to go to Mars,聽all of聽that stuff.鈥澛燗nd that excitement has been聽procured聽at the risk of attention being paid to the potential difficulties that are coming. And I think聽probably it's聽become an arena in which people want to emphasise so much of the good that聽they've聽paid less attention to the bad, but we need to do both. And I think the other side of this conversation about you know why we聽haven't聽paid attention to the bad is that聽it's聽difficult for people to understand. It requires you to know something about how quantum computers might work, about quantum mechanics, even the terminology is difficult. And聽it's聽like asking, you know, primary school students to read Charles Dickens or Henry James,聽and not being able to get there for聽a very long聽time.

惭补谤办听厂肠辞迟迟听听13:53

Yeah, what about our readiness to deal with this quantum world? I mean, here we are at the university, as you think through the need to have the quantum physicists who are available, those really understand the hardware and the software challenges, and to even be able to do the kind of forward thinking, even the philosophical thinking about these changes. You know,聽what's聽your read of our state of readiness?

狈补濒颈苍颈听闯辞蝉丑颈听听14:22

I think聽we're聽not ready at all, especially in Australia. And I think聽probably you聽might聽modify聽that statement elsewhere.聽There's聽a lot of exploration going on about these potential new protocols. We have suggested protocols that have been put forward as the ones that we should adopt from the National Institute of Standards and Technology in the US. People are still working on those, so we have that kind of angle to explore, but to聽invent new algorithms聽requires new mathematical ideas.聽It's聽like the factoring issue: we are converting things to numbers, we are producing large numbers, we have efficient implementations of protocols, even though these are unimaginably large numbers. But we need other ideas to create efficient protocols that will protect us even more. And not聽all of聽those angles are being explored. So even the ones that聽we're聽currently adopting, that Apple and Google and聽Signal have all adopted, have problems. They have gaps. We聽can't聽use them in every setting, so聽yes, we can use them to protect our message history, but how do we protect the tiny little parts of the internet?聽They're聽called the transport layer sockets, where you need things that are much more efficient in聽different ways. We聽don't聽have anything for those.

惭补谤办听厂肠辞迟迟听听16:03

Is part of the capability challenge around this, to be able to draw people from a wide array of disciplinary backgrounds and them to put their best thinking on the impact of their discipline in a quantum world?聽I mean,聽I'm聽interested in your pathway as a mathematician to now with a big piece of research聽that's聽coming around, the application of your mathematics given these quantum challenges.

狈补濒颈苍颈听闯辞蝉丑颈听听16:33

Yes, interdisciplinarity is essential, but I'm also struck by the fact that when you talk to somebody who works in, say, quantum information theory or people who are working in, say, search algorithms and optimization, each of them doesn't quite know where聽the questions are, where the dialog should be,聽how to benchmark each other's results.聽So聽all of聽that conversation聽has to聽happen with the common outlook that comes from using mathematics, common language, common ideas. And you know, I talk to聽people from very聽high-level聽universities, and I say to them,聽鈥渨hy聽didn't you think about using this?鈥澛燗nd they said,聽鈥渙h, we聽didn't聽know that existed.鈥澛燬o聽it's聽very sparse. The common knowledge is very sparse between all those directions that need to talk to each other.

惭补谤办听厂肠辞迟迟听听17:42

So聽let's聽talk in practical terms about what聽you're聽doing here at the university, because聽you've聽just secured funding to tackle this cybersecurity problem with a team of top minds coming at it through a mathematical lens.聽So,聽tell us about this project that聽you're聽leading, and聽tell us about聽MathQuEST.

狈补濒颈苍颈听闯辞蝉丑颈听听18:00

So聽MathQuEST聽stands for聽Mathematics for聽Quantum聽Era聽Security and聽Trust, and聽it's聽a聽Centre聽of聽Excellence聽that's聽just been awarded by the Australian Research Council.聽We're聽bringing together mathematicians, people who work in cryptography, people who work in security of many various directions, differential privacy, optimization theory, and all of them are going to be coming together to tackle some fundamental issues for these gaps that I spoke about. We have nine universities involved,聽we聽have partner organisations, government bodies.聽I'm聽really excited about what聽we've聽been able to bring together so far, but聽I'm聽also aware of the challenges.聽It's聽going to be hard for every area to understand each other's language, so聽we're聽going to try by bringing together those common conversations,聽first of all, into being. But at the same time, there's this other side of making people in Australia aware, not just ordinary people, but also people in companies, people in government bodies,聽you know, the mums and dads who need to know about what their children might be accessing.聽All of聽these directions need to be covered.聽It's聽a daunting prospect, actually, so聽somehow聽we聽have to聽reach everyone and at the same time produce some fundamental聽new ideas. Of course, I come from the fundamental side of things, but I聽am incredibly excited by the prospect that the fundamental things聽I've聽been doing, which sound esoteric to most people,聽will turn out to be a lifesaver.聽

惭补谤办听厂肠辞迟迟听听19:44

And聽can聽you聽talk a little bit about your almost academic and disciplinary pathway from mathematics,聽applied mathematics, but mathematics through to聽kind of dealing聽with something so specific and futuristic and challenging as this cybersecurity challenge?

狈补濒颈苍颈听闯辞蝉丑颈听听20:04

So,聽for most of my career,聽I've聽worked on mathematical models that help us understand how nonlinear phenomena work. So nonlinear is a term聽that's聽thrown about all over the place, but聽it's聽defined in terms of a negative so let me explain the positive side.聽So,聽if you take, say, two rulers and stack one on top of the other, then you know that the length of the combined object is the sum of the lengths of each individual ruler.聽That's聽an example of a linear system. If you have a solution of such a system, then you can add solutions and still get聽new solutions. So,聽that's聽very well understood.聽All聽of聽our applied mathematical tools, or many of them,聽are built on that basis that we have this structure.聽But聽almost everything聽we look at in the world is not linear.聽It's聽not as simple as that. If you look at how the聽COVID聽pandemic ripped through our populations, you know, the number of infected people on one聽day聽isn't聽the sum of the infections on the previous two days.聽It's聽the same with the weather.聽It's聽never the average, not always but you know, not the average, usually, of the previous two days.聽You look at waves at the聽beach,聽tsunamis are not the sums of anything else.聽So聽you need new methods, new tools, and those are the kinds of things聽I've聽been developing.聽Now along the way, it turns out that the models聽I've聽spent most of my career on have turned out to be incredibly impactful in areas that were unexpected. Things like estimating how boarding times on聽aircraft聽work, how bus arrival system might work.聽So,聽although they were fundamental objects, they turned out to be useful. You know, this is a way聽of聽opening up聽new pathways in your聽brain,聽almost.聽When you discover something for which you can predict ideas,聽behavior, it turns out to open everybody else's mind towards,聽鈥渙h yeah, that's how we explain this other聽thing that we could never explain before.鈥澛燭hat's聽the unusual way in which mathematics has become fundamental to all the sciences. It gives you a new way of thinking. Now, going from that fundamental side to the next stage of my journey, I realised that the ones that I study, the models that I study,聽are聽actually聽sort聽of evanescent versions of the constructs that underlie certain types of cybersecurity.聽So,聽in this cybersecurity setting, which is called elliptic curve cryptography, you take certain curves. These curves have lines going through them.聽Of course, they intersect. You have mappings that go from points to other points on the same curve. But the systems I study go from one such curve to another one.聽So,聽you're聽moving constantly.聽You're聽not staying on the same curve. And it turns out that gives you different phenomena that you might be able to use to create new cryptographic protocols. And that was like a light bulb moment for me, and I suddenly realized that there's this other incredible聽vista聽that we could try and explore, even with that particular type of knowledge that I came with, and that there were other such settings that one could use from mathematics.聽So,聽a fundamental idea here is the idea聽of聽non-commutativity.聽So,聽this is a fancy word for saying the order of operations matters.聽So聽you know this in real life, because when you put your shoes听补苍诲听socks聽on in the morning, you always put your socks on then your shoes.聽But,聽what happens if you did it the other way around?聽It's聽not terribly good,聽it's聽not comfortable. You put your shoes on then your socks.聽And聽that's聽an example of a聽non-commutative聽operation. The order matters. It turns out that in many of these contexts, the ones I spoke of going from one curve to another, or if聽you're聽thinking about other mathematical objects that we might use for cryptography, the settings give you non-commutative operations. And the weakness that I spoke of,聽the Shor's algorithm,聽assumes you have commutativity, you have things where the order of operation聽doesn't聽matter. And the exploration of this direction of whether聽non-commutative聽operations might give you more has been聽initiated,聽it's聽been started, but聽there are lots of directions that聽still remain聽unexplored,听补苍诲听that's聽what聽we're聽going to be looking at.

惭补谤办听厂肠辞迟迟听听25:06

Have you found the discovery of these applications for your聽initial聽disciplinary strength and insights exhilarating? Are you excited when you think through how this all could have a profound impact?

狈补濒颈苍颈听闯辞蝉丑颈听听25:20

Oh, absolutely.聽That's聽why I always think about mathematics as a creative聽art聽actually, because聽it's聽that suddenly seeing something,聽like the cubits must have seen in, you know, the art that was produced by people like Pablo Picasso and Braque and so on. The ability to see something from a different angle that one would not have done before,聽colours聽in聽a different way.聽That's聽just a聽mind-blowing聽experience, and聽that's聽why I do mathematics, because of that.

惭补谤办听厂肠辞迟迟听听25:53

And just finally, I know聽you've聽got a great passion for mathematics, all the way back into schools and to increase participation rates in mathematics and participation聽rates for聽for聽girls in particular. How do you convey that exhilaration and the practical manifestation of the power of mathematics? Do you聽think to聽young聽people so they聽can be as excited about it as you are about it?

狈补濒颈苍颈听闯辞蝉丑颈听听26:18

So聽I try and talk,聽lots and lots of聽talks. I go to聽schools.聽I was interviewed by Michael Kirby聽actually, for my old school, Fort聽Street.聽And I give talks聽at聽speech days. I try to talk individually to two children and two parents. But聽it's聽not just showing subject matter information. I聽think,聽in particular, for聽young people聽it's聽a question of seeing agency and discovery, a power that comes from not necessarily having to accept the templates that are constantly being thrown at you. And for girls, that template is,聽鈥渘o, you聽can't聽do mathematics. No, you should try and get married first. You should do things that are caring for other people first.鈥澛燭hose kinds of things聽are what I try to counter.

惭补谤办听厂肠辞迟迟听听27:20

That's聽Payne-Scott聽Professor Nalini Joshi from the University of Sydney, now also the聽centre聽director of聽MathQuEST聽and the 2025 New South Wales聽Scientist of the聽Year. You also heard from Prachi, a PhD student at the University of Sydney聽Nanoscience聽Hub. If聽you're聽inspired by the power and聽magic of聽mathematics,聽you'll聽also enjoy our episode with Eddie聽Wu,聽the high school teacher聽trying to bring that magic to life for his students.

贰诲诲颈别听奥辞辞听听27:52

Growing up, I never聽really fully聽grasped what聽maths聽was about.聽I've聽struggled with聽maths聽all my life. In fact, I聽kind of still聽do. I think聽that's聽one of the secrets to how I can teach effectively, because I still have empathy with the people聽I'm聽trying to help learn.

惭补谤办听厂肠辞迟迟听听28:09

You can listen to that episode of聽The聽Solutionists right now. If you want to hear how the best minds in the world are tackling our biggest challenges, make sure you follow the show in your聽favourite聽podcast聽app聽so you聽don't聽miss an episode. The聽Solutionists is a podcast from the University of Sydney produced by聽顿别补诲蝉别迟听厂迟耻诲颈辞蝉.聽

The Solutionists is a podcast from the University of Sydney, produced by聽. Keep up to date with聽The Solutionists聽by following @sydney_uni聽on聽听补苍诲听, and @sydney.edu.au on聽.

This episode was produced by Liam Riordan with聽sound聽design by Jeremy Wilmot. Supervising producer is Sarah Dabro. Executive editors are Kellie Riordan, Jen Peterson-Ward, and Mark Scott.聽Strategist聽is Ann Chesterman.

This podcast was recorded on the land of the Gadigal people of the Eora nation. For thousands of years, across innumerable generations, knowledge has been taught,聽shared聽and exchanged here. We pay respect to elders past and present and extend that respect to all Aboriginal and Torres Strait Islander people.