>> Hello defcon, I'm happy to be here. They asked me if it was my first time speaking I said yes and no from sky talks was a smaller room so happy to see so many people. So talking about quantum computer. How do you know how quantum works or quantum -- so this is very basic that you have to know. Complex number -- obviously so if you don't know these please leave the room. I'm kidding. The nice thing I will say that you don't need to get this stuff to understanding quantum computing -- lost audio -- I will try to convince you that. Outline, I will be talking very broad but I will not go into technical details so how things work and I will give you the ideas and applications. Very brief crash course of quantum computing. So based on quantum mechanisms about you see the operating system of nature on nature like the framework on top which the gravity -- nuclear forces are running so you get series in -- and you try to adapt them to do quantum mechanics. There is my only side about quantum mechanics. What it says that the particles in the universe like electrons and protons they behave randomly but not not inception they are not predictable. But you have no way to predict what is going to happen but what is different compared to what the randomness can be negative this is problem but negative and complex numbers. So that seems to be counter intuitive and you have to trust me that it does make sense mathematically. So -- (lost audio) -- so when you have not looked as the Q bit it is in the state that if you observe the Q bit and ask what is value it is zero with property and some other property. Coefficients and -- of the straight line and the bracket is called the bracket notation you don't need to remember this but what you need to know that is alpha and beta used called -- so they can be a negative or complex and the property so you take this value and square it and that property that is what you get so a number between zero and one. You have different properties for each byte. Sequence of eight quantum bytes maybe it will be 0X or 00 and so on. And using these objects like quantum computer you have registered which can we -- anything you want and you will transform the state so that is how you will compute. You will have kind of quantum assembly but you have will different restrictions. The importance to remember that will be reversible but can go back in the past so for your information you don't have classical assembly you have end operation register one or two and then you register one and you can't go back in the past not the previous value and here you have what you modify so quantum objects about you just chain the properties what you learned in high school in algebra so just do multiplication and transfer the property and when you properties go to one you want -- sum to one as well. I will not go more technical but that is idea remember that quantum computing is multiple together some properties of complex. And that is it. So you have this set of register that can be bot on the same time and at the end you observe one bit or more and that your result. And the importance thing is that you cannot simulate this using quantum computer say you have a quantum byte it is encoded 256 different properties so you might be able to start this on the normal computer but now say you have a quantum motor of two bits. How do you start this classically might be doable but if you have 64 bits cannot start this on the classic computer. So can try this online there are some simulators you cannot go too far. Multiple vision for all of this was to simulate quantum physics and for some reason that you cannot simulate the quantum computer -- so a friend of said okay to simulate this we need to simulate a quantum computer and to understand how physics or nature works by submitting all the quantum phenomenon. I will just go through to common misunderstanding about this and people say quantum computer that is super faster and way faster and solves problems but bad news doesn't solve all the problems. I don't know if it is familiar to you -- where you list of cities and you have to find the best route. All have problems have some structure that makes them difficult and practically impossible to solve on a normal computer. You will not solve these hard problems on the computer. The good news is you do have quantum speed up for some specifications making the impossible possible on the quantum computer and going from N to P times Q is difficult on the normal computer but easy on the quantum computer so the application is -- I will talk about this later. So the last caveat is some people say you have the super notion trying everything the person for free -- that is not the idea, the idea is in some sense several values of the same time but you can only look at one result but like all of this is useless and you cannot say I want to look at result that gives this value. You look at the random results so no magic here. So that was it for the tear. Let's move to practical part. Like I said -- we know how to factor 15. Three times five. We also know how to factor 153 and 56,123. But that is caveat here for these numbers they use special -- about in some sense they have to know in advance what was the solution before searching for the solution. I want to say that we have very far from the use application of quantum computer and the reason is it is difficult to build. First of all you is have to find a object to simulate your Q bit so you will take some physical particle and sometimes foreign molecules -- the main problems they are facing in quantum computer is that what is -- interact with the rest of the system and this will complicate the system -- you can correct all your -- in time but in practice much more difficult. You have to computer temperature plus absolute zero. And we don't know how to scale to several hundreds or thousands of Q bits so we have to result four or 5Q bits but if you want to break all the crypts in the world you need a thousand and we are far from this. 9Q bits this year not a actual quantum computer just a set of 9Q bit that's can live together for a few seconds while correcting -- in the environment. Lost audio -- I don't think they do. They probably don't but -- so like I said -- RSA -- explain why RSA this is based on factoring numbers. If you can factor numbers then you can break RSA and then factor numbers so it is hard with computer we don't have a math proof of this but we convinced that is our problem. Factoring is not complete but easy on the quantum computer. Doing a quantum for transform and gives you the result. And what is nice within is not specific for factoring, it is for a whole class of problems that we call the -- fighting a subgroup ribosome bigger group and turns out that the disc algorithm is another time of this problem. So the problem behind the -- problem is you have number G and you know a G to power of Y and you don't know why so you look for Y. You can try it. It's not easy if you do it only big numbers. And again, it easy on the quantum computer. So what about -- or has functions. A little bit faster than is quantum computer but not that faster just that is search for the key would be much faster. So you get half of 64 bits of security. If you do some advance math if I want 120 bit security I need a key off to 56 and we have version of 256 and we not have -- of 12 bits and the reason behind this -- we can search in a table of elements in time square with N instead of M. So if you have two to the N -- so there is a field called post quantum crypting to fee and goal is the find alternatives. Lost audio -- means equations with many variables and the variables are come fined in such a way with multiplication and once you have that much much harder to solve. You do multiplication it is harder so impossible. But if you want the use it, most of time you need the have a shorter system. You need to have some trace structure and that reason why some -- working I don't -- now something important to understand, someone has quantum computer that created it might break -- you can still signatures but issuing knew ones with a quantum system. But if you encrypt something with a nonquantum safe cipher it is too late and going to be encrypted and no use to encrypt again. So the bottom line here is more important the have quantum encryption you can still wait until the quantum computer is created. So two types of encryption techniques so nothing new. Ideas from 70s or 80s. We have very large keys kilo bytes but today we have tera byte but maybe kilo bytes not big data. And the other one is -- very simple to understand you have function and you don't know the function you know what it looks like and you want to learn the function. So you cannot guess how it works. So fifth part is quantum distribution. Here the problem is like a quantum -- instead of using -- you use physical phenomenon. Not really quantum computing but using quantum mechanics. The argument is that if you are in the middle you can't do the middle because it will be detected by the law of physics. It will be modified so you will see the modification you cannot copy quantum bits. And are random. So this one is the -- BB8 h invited by the guys in 1984. This is simple. They want -- so likes a few bits and she has to select encoding. Here it means just position of the -- you can see just simple encoding. So she says blue-green green and she will send this to bob and he doesn't know the encoding and thing is if you have the same encoding you will observe the right value and if you don't have the -- it will be too late to correct because once you observe it, it is not a quantum bit. So bob he observes the bits that he receives and then he publishing encoding and Alice says you have the right or wrong one and it just pick the bits why you have same -- so the scheme is more complicated but that is general idea. But it is not as secure as it pretends to be. The first one is it is quantum when you use the keys when you store it in your system you use classical -- so the people say classical -- yes, but then what do you do, you have to use classical crypt. In practice you to -- quantum hacking and broke some of the first systems. You can do this over the internet and dedicated optical fiber links so point to point and limited in distance less than a hundred km. You can put repeaters or make -- now it is a bit annoying. So that application is quantum computer if you wonder why I put this here. I don't know if you recognize this guy. Leverage the no claim principle. The idea is simple. The idea is when you have quantum bits you can know like momentum but you know bot at the same time. You cannot know everything about the quantum object so if you don't know everything you cannot copy it. You cannot copy what you don't know. In physics you have this -- that cannot clone a physical object to exact copy. So you see the relation with quantum cash. You will put some Q bits on your bank note and so only the bank can create the ones. So that is suggest a experiment and not practical because it is difficult to put Q bits on the note and to deal currency problem. So you will never see this for real but you can imagine. You can imagine software -- so using this idea of quantum non-cloning, so you have function here in green the -- let's say you find you get the code of function and maybe sophisticated but you can reverse the code. You check the hash, if a strong hash you not find the password easily. And if you have binary you can copy the bytes. So here is idea of prediction that you cannot copy the program. You have the problem which is a list of Q bits and you have no idea about what the program is doing. So like quantum cash it is not something that will happen for real. So my last one is about learning. Seems to be hot these days. I have seen some very good talks and not so nice talks. So one slide difficult to summarize but see the science of getting computer -- it is either learning patterns or -- notion of supervised -- un-supervised like discovering patterns and it is quite a success and feels like for detection -- usually better at finding similarities that no monies and intern detection for example we went to find monies for specific notion of no money. But security -- lots of false positive the mission learning. Recommend something that you don't want the see it is not a big deal but if you -- system or detects too much you have a problem. Some companies claim the use it but sometimes just say we will use mission learning just to say they use mission learning. I have not seen detail about this so I don't think it works as claim. Some people have been trying to -- mission learning. But a bit boring because not a brand new algorithm, just take the algorithm and run them on your quantum computer. Things like clustering. There are two advantages and one sometimes you have search in the big list of data, so you can use what was seen before to speed up the search and you have the square root improvement. You do get a exponential speed up which means it is something you could not do on classical computer but you need a quantum ram. So the idea is out there. You give a address and get the value add this address so in quantum memory -- and you receive the values at these addresses in superposition. I have no idea how the implement this and physicist have no ideas. And the idea of quantum learning -- so if you have a quantitative you don't have quantum -- so will be useless. So time to conclude? Maybe you were not happy about this and you will be leaving the room. It sucks. Doesn't even solve problems. So -- this is an article but if you are more opt mystic person you will see it differently. Stuff collecting all the -- if you are math -- transforming a physical state. You can take this microphone a bunch of atoms you can see the wall is big quantum computer allowing da. What is universe computing. So what some physicist say we don't know if it is possible to have a quantum mechanics but if we have proof that is poses then it will tell us about physics. So even if we fail we win something. So I hope you liked this. If you have questions, I will put the slides at line. I have just been interested in this stuff for years and years. So if you want to build a quantum computer don't talk to me. Yeah. I have a few minutes left. When I did this talk people ask me why don't you talk about the company that is selling a computer. This is recorded. So the company selling the quantum computer, it is a different type and it cannot factor big numbers. So that's it. Thank you for you attention and I am happy the take questions.