Hallo und herzlich willkommen zurück auf dem Kanal der Femme. Unser erster Talk heute ist von Nex. Den kennt ihr wahrscheinlich schon als Herad. Hi and welcome back to the Femme Channel. Our first talk today is held by Nex. You may know him, he is a Herad. And he studied at university and he has a very quick... Es gibt danach noch ein Q&A, um Fragen zu stellen. He has a common problem. He can't read his own handwriting. So he wanted to take notes during lectures, using Bautech. Wait, that's not possible, is it? You will see. You can use our usual hashtags that can be found under the stream. To ask questions and also the chat. Dass man die Mathevorlesung nicht in der Datik schreiben kann. When I was a first semester at the Technical University, a lecturer said that you can't take notes in Lartisch. I took that as a challenge. Wie ich es am Ende doch hingekriegt habe, meine Mathevorlesung in Lartisch. I tried around a little bit and today I will show you how I managed to take notes in my math class. I have been a student of computer science since 2018. I have been working in Lartisch since the end of my school days. Quick typing, I always carry out my laptop and in 2018 and 2019 I took notes in my math class life using Lartisch. Today I will show you why you might want to do that as well or why you might not do it. And I will show you some current situations that you may encounter in how to deal with that. So why should you even take notes digitally? I myself don't have a good handwriting. It's not very legible and I want a document that I can read and that others can also read. Maybe because they missed the lecture because they were sick. Also corrections are very easy because often times lectures correct. Notes on the blackboard and you can't do the same if you do it all by hand and then you have to cross it all out and that's a waste. Also using Control F and A, an Index, it's very easy to use the notes. And look up things and at the end of course the script looks very nice and you don't have to invest a lot. But why Lartisch? Because there's so many things that would intuitively speak against it. The backslash is not very easy to reach on German keyboards. But you need it in Lartisch all the time. That may be a bit difficult. And of course we work with a source code that is not as nicely legible as what you see is what you get. And of course we must compile the document again and again during the lecture to see what it looks like. And if you didn't put any mistakes into your mathematical formulas, which is a recurring error, maybe you left out a curly bracket. This is very difficult to see in the source code so you have to compile all the time in order to be able to spot that. Of course the compiler will give you a lot of trouble if you forget a curly bracket and that may be difficult during a lecture where you have to comment out the line and look for the mistake later. Another advantage of course is the really good character set. Lartisch was developed by mathematicians for mathematicians. And of course you have all those special characters. And we can also define our own macros for special operators, shortcuts and text elements. So we can build for ourselves a very handy and usable Lartisch. So we don't have to insert spacing for example into the source code. And you can also change things later. You don't have to click around using your mouse and switch between keyboard and mouse, which is very handy. And of course an important reason to use Lartisch is it's just cool. Also preparing, you can't go unprepared. So before you go to the lecture, you need a text editor in a PDF viewer. Optimally, that one will also have syntax highlighting and be able to build the PDF directly Maybe using macros is also useful. As a PDF viewer, I can recommend KDE. For example, that makes it very easy to reload the PDF automatically so that you don't have to switch into the PDF viewer to see your results. But instead be able to have the PDF viewer open all of the time and reload automatically. Some editors have an integrated PDF reader that you can run in parallel so that the source code is synchronized with the PDF so that you always see the current source code line in the PDF highlighted. What you also need is Lartisch, so you need some of the other tech distributions. I recommend Techline for Linux, for example, or Mac-Tech for if you have a Mac, or any other large tech distribution. The tools differ, but the basic properties are almost the same. Of course we have to prepare some shortcuts and commands for different text elements and symbols so that everything looks nice and you don't have to tally a computer. Please put this paragraph here. This should all be prepared. Depending on which editor you use, the setup differs. You can define shortcuts for environments that you use often, or macros for editors such as Atom, or VS Code. But grundsätzlich, there's some pre-built buttons to compile the document. But you can also have a terminal open and run the commands. I like having a make file next to the tech file to compile the PDF. Und dann sage ich einfach nur noch meinem Editor. And maybe if I need additional tools to compile pictures or images, I have hotkeys for make. Und in the end I just need a few keyboard macros for frequently used environments to insert them quickly without having to hand type them. Und dann, we will prepare classes and packets, because the goal is that we have a unified design and have reusable packages. We want to separate design and content. So we want two different files, one with the content and the other with just the design. You can do that using classes and self-defined packages in Lattich. This is basically the same as the preambles. Some details differ. For example, you need to specify the tech version. But you can find all the details on C10 in the CLS Guide. You can just look them up. So, it's not that different from a normal document preambles. So, which packages do we need? Of course we need some of the standard packages, such as BabelInfoDank and Fontank. Of course the math packages such as AMS Math, AMS THM Math Tools etc. In einem Paket, damit habe ich schon mal sichergestellt, dass all the CMS packages I might need into one package. This ensures that all symbols I might need during the lecture are already there and I don't have to squabble around with package not found messages. And I know that if a command doesn't exist, it's not because of my packages. For plotting, I like to use ticks and pgf and additional pgf plots. For standardized commands and environments, we have to define some text elements. We'll use that later. Definitions-Proofs are often needed in math. Electrists and it's worth having your own markup there. And also commands, images and tables are often used.   Und so, ja, these kinds of packages are always worth, always loading as the last thing in the class file. Hier, we also might need some commands prepared for, for example, the terms that I used in the lecture, or maybe adding a certain kind of table of contents or a header sheet, or maybe, yeah, a list of contents and stuff like that. That maybe should be packaged into its own command as well, so it can be easily inserted later. And what is also very convenient for the document header is packaging those into a separate environment, so that in the later document, in the end where the lecture is written, you really only have to open up this one lecture environment and it immediately will load all of the necessary sheets like the header sheet and the individual heading stuff and then you can just add the content. And some settings that you might want, like the parent class for SCR-Report is, for example, a good one for lectures and for maybe homework, SCR-Article is also a good option that is just up to the taste of the writer. And for the font size and stuff, you can use the comma options command, how exactly that is used. You ideally look up in the documentation of a comma script, and it's actually very, very well explained here. For header and footlines, I already said, I like to use SCR-Layer, SCR-Page. That's a continuation of SCR-Page 2 and that way we can specify the layout and design of the header and footlines. And for the directories and such things, we sometimes also have to do some specifications and the metadata we usually do with Hyperref. There's a small example here again. And this is the definitions that I did. The header lines, the footlines, this is without footlines in this case. I put the page number to the side and then the inner part of the header line I put in the heading. And that way we always can see where exactly this page is in the scheme of the lecture. And I also mentioned here the table of contents and the glossary and I specified where exactly it's supposed to be and what size it is. In the end, there's a small command that says how I want to output this table. I always want to say that it starts on the right page, so I do a clear double-page command. And that's how I do that. I build a new command that does first clear double-page and then prints the index. And then lastly, I specify the PDF title and the author using the PDF title and PDF author. So in the end, the Preamble should be actually very simple and short. It should really only say what class you're using. For example, lecture, homework, whatever. Then the title of the lecture, who is presenting it, maybe if it's a homework, what number homework it is. If you're writing down a protocol of something, then maybe the number of your matriculation number. But something else should really not be in the Preamble. And then in the end, a very minimal example can look like this. You can see it's very simple. There's only the document class loaded here. We set the title and the author. And in the end, there's just the document environment where we put our content into the lecture environment that we can freely define to have a very quickly and quick and easy document header and such.  So, let's get to the prepared commands and environments. For that we might need some various text elements, maybe some sentences or proofs. We also might want those automatically added to some sort of index. Maybe also references to slides that we want to refer to. Maybe you don't know that in advance, so it can often happen that you have to define those on the fly. And then from my study, for example, the degree or some other certain mathematical terms, maybe a symbol to add a small tick for something for a part of a proof that has been done and such things are usually convenient to have as a separate macro. And then for other constructs like integrals or vectors, it's also often is worth having one's own shortcuts for all the distances used and such things and differential operators and all the things where you have personal preferences about their specific syntax. So, this is the environment that I like to use. I do this with an SDHM. So I did a new clearance environment with a DL definition. And this is always reset when I do a new chapter. And so I always know how many I have in each chapter. And I also build another macro here that specifies the name of the thing I'm currently defining. So, for example, I want this to be printed in bold print und then to set it apart from the rest of the text. I also specify a new environment here, which I call definition. And then I add a little bit of padding before and after and center the thing and make it a bit smaller. So it really separates itself from the normal text. So I can easily see that this is a definition. I can do the same thing for proofs, for example. So, I want this more in the text. I don't really separate it from the normal text, but it also has its own environment because I do want to ensure that the QED symbol in the end is always added. And I do this using pushQED and popQED. And also, as to be safe, I also redefine the QED symbol. So whenever I use the QED symbol twice in here, I ensure that it is never printed twice and it just doesn't have a consequence, if I add it manually. And then there are some more symbols here that I often use. There's, for example, something that I often had to use. A special German math term. And such things are added here with their exact spacing between the letters. And also that's in such a way that it is displayed nicely in the text. And not like a variable. Then there's also the differential operator here that I don't like to have printed cursive in Italics. And then I also added a special integral where I like to have a little bit of space between the formula and the dx at the end of the integral. Then there are some other examples here. For example, the Juller number E that I like to have displayed a bit differently. How exactly you want to do this is, of course, up to you. And you just have to see what your personal taste is. This is just how I personally like it and how I edit it during my lectures. And yeah, that's basically the live part now. So, during the lecture, you should have a few things open, your favorite text editor for the light tag document. And also ideally at least some package that you wrote yourself. Because it can happen that you might have to redefine some symbols during the lecture. Then you have to really quickly switch to the package and maybe add some definitions. And then it's also worth it to have the lock open. I can do that in Vim using set-autorate-only. So I can't just type around in there. And it also automatically reloads. And then I have an editor there where I can very quickly see what the problems of compilation might have been. And then lastly I have my PDF viewer, of course, which should also automatically refresh when the PDF changes. And that should display the generated PDF. So I can always see the result and can quickly correct a mathematical equation if there's a brace missing somewhere or a bracket. And lastly, the documentation of light tag and all of its commands and symbols. You probably won't know all of them by your own in the beginning. So I recommend the documentation from Wikibooks. It has a really good overview of all the terms and symbols that are often used in mathematics and also all of the letters of the Greek alphabet to be used. And the variations of various letters and how they look. It also shows how they look. Then there's also some instructions on how to use some of the mathematical operations. So, about the mathematical sentence. So sometimes I want to, for example, specify some variables or functions and so I want them in line of the text sometimes, which I often call inline math and in modern Leitech that is usually done with backslash panthesis open and backslash panthesis closed. And that is usually set into a more compact math environment that doesn't exceed the height of the line and so that integrates well into the normal text and is very convenient for variable names and function names and small terms. If you have louder terms and usually want to have them separate then usually use backslash bracket and backslash closed bracket. Everything that is contained in there will usually be displayed in a separate line. It's not within the text line and centered and that way one can also use some larger symbols and is very convenient for larger equations such as larger symbols in equations and also and and these limits and stuff can be more easily displayed. And that's what this specially set environment is used for. There are even more environments for sequences of equations. They can specify a symbol like for example there's the syntax that you can use similar to tables from Laetag that specified where exactly the individual equations are supposed to be lined up with each other. I use it here with a line environment and there's the ampersand here that is right before the equality signs and is used to align those with each other. And then once you have a very big sequence of equations where you maybe reform an equation you can just have them right below each other and have them nicely lining up and that is of course also centered and has its own block. But also what's very interesting there is that there's on the right side a enumeration of numbers to specify where exactly you want them. If you do not want to display them you can use the aligned star environment and then you don't have those numbers. You can also do this with multiple columns if you want to. For example if you have two similar equations that you want to calculate right next to each other. For example here's a some set equations and then you can use the backslash to start a new line and then these very similar things are written right below each other and depending on whether I want to skip to the next column or the next row I of course use the ampersand or the backslashes and then of course those are all used again to the alignment. And then again during the lecture it can happen that you have to add additional symbols that you didn't know before and in that case you need to react quickly and maybe look up the documentation on the bookiebooks that's just a normal lookup there are also some other symbol tables that one can use and during the packed documentation of course there are complete tables where everything is in there but if one doesn't find them there very quickly you should rather just define a placeholder and then maybe after the lecture fix that up with drawings I can only say good luck usually drawings are much too complicated to do within the lecture maybe you can do some quick things with pgf plots and also maybe some really small stuff with tics but if it's more complex like for example this can't just easily be sketched within the lecture in a very short time so you can use the coordinates for example and the people that actually write the lecture on the blackboard they just do a quick sketch that is not perfectly aligned so it's very hard to actually, if just from your mind write it down in such a way that it looks good and you will always spend much too much time on this and to make it look great there are also some other options of course you can add some image formats like xfag or gimp or inkscape that you can use to manually draw and with svgs unfortunately you need the svg package for latex and since latex can't just use svgs directly they need to be rendered externally and for that you also need inkscape so that is sometimes a bit difficult if you use foreign latex documents, which is a safety risk because the latex document can essentially execute whatever commands you specified and if you don't want to draw them yourself then of course you can also use wikipedia and other creative commons licensed images and svgs and there are lots available in the various sources but of course you have to add them and that's essentially everything that you need to really write along a lecture in latex müssen die zum Beispiel jetzt noch neue Symbole korrigieren die wir vorher noch nicht hatten das heißt wenn wir die jetzt durch die passenden Symbole ersetzen die wir vorher noch recherchieren und jetzt einführen müssen dann ist jetzt you need to put in the symbols to find your own symbols or finish open drawings that you weren't able to finish you can do that afterwards and also if you had problems with images during the lecture you have to fix that afterwards so these are the to do's you can use the classical to do comments but there is also the to do notes package which gives you different possibilities to highlight, to do either as in a final version at the borders of the PDF even in different colors and of course you can also hide them during the final version and this is basically all you need to take notes during lectures in latex so it's up to your own taste what it looks like in the end just try out what you like and what works for you and then just hope that you'll be able to take notes quickly enough so have fun I wish you the best success yeah thank you I'm sure that your fellow students appreciate your notes we'll have a short Q&A in the IOC and you can also find us on Twitter and in the Fediverse to ask questions so let's start with the Q&A first question what are opal sets ja, so I often had the issue that during lectures, especially during proofs there were references to for example equations that were done before and definitions that were done before and those often were written with some special arrows or just normal equal signs and for that there's the Overset command that you can use to have while the symbol in one place and then also add another symbol on top of the original symbol that usually looks to do it in such a way that the spacing is still good and that the full width of the original sign is used again in the space so you sometimes have to be a bit careful if you do it in a longer text especially if you do it in a line environment that messes up the alignment a bit and the centering because it's a little bit wider than the original equality sign but ja, then of course there's also the underset which is the same idea but the additional symbol is listed below so there's a little example here this would be a symbol that I've used in computer engineering a lot to say if one variable follows another and that's a usual application of such an underset just a way to add these little annotations to other symbols next question how much time did you need for the preparation for all the basics ja for me it was definitely a very incremental process so in the beginning I only really thought about the rough document structure and had some experience because I also during my school time tried to digitize my school notes for a while and so I had a basic idea of how the document was supposed to look so that was the stuff I was able to prepare but then I also learned a bit more about how to build class files and packages and then all the rest especially all the experience of what kinds of symbols do I need and how do I get the documentation stuff that stuff that happens during the lectures so in the beginning it was very often that I had to do some handwritten notes because I was overwhelmed by the latex thing because some things were missing and then I had to change those afterwards especially in the beginning many parts of the lecture I really had to look at after the lecture and digitize only them so that sounds like a painful learning process yeah, but once you've really prepared it's a really worth the effort and then you really don't have to think about it a lot more so if I've done it once I can really go into a lecture and spontaneously if I have to notice oh I really have to take some notes then I can really quickly add the preamble and then if I've just copied it in then I can actually start it really quickly it's really something that you really have to do only once okay a question whether you can show us examples from lecture notes that might be a bit difficult the notes I took are well the code is not entirely mine I have written almost everything myself in the beginning but there are also some that I have been done by by other students that did it together with me and I didn't really ask them if I was allowed to publicize this so I am not actually gonna link anything so the complete results you can find in the computer science wiki of the technical university of of iminal and maybe you can find something there using some contact es geht genau in die gleiche Richtung okay next questions are your packages and templates public yeah no it's the same thing even there no it's not entirely my code so I don't really have the permission to publish but in the end you have seen quite a few except and I also have added some a handout to pre-talks there are also a bunch of examples there it's not really much more that can be seen there and it's not much missing from there to the actual production setup and some things I maybe add it afterwards but almost everything is pretty much exactly what I've presented here in the slides okay so directly to the lecture someone is asking how much do you actively how much are you actually able to listen to the lecture when you're so busy taking notes yeah that does happen but since I'm actually on the computer since I was faster with the computer than taking notes by hand in the end I do think that I noticed a bit more especially when during the preparation for exams I went through the entire thing I did notice a lot of individual points where I was oh hey I actually did that during the lecture I didn't even remember so that does happen there's a lot where you just have to write down the content of the lecture and it goes in and out of your brain with no retention but that's just the way it is when you take a lot of notes you don't really have the time to think one of the last questions which keyboard layout do you use for me I used the quartz layout I tried to switch to Neo2 which apparently does have some advantages especially for lots of these special symbols that I used in latex for example the backslash on quartz layouts is much more easily reachable I've already seen that in the comments yeah so but I have my experience with quartz and that's what I'm used to but I assume that many people that will start in university will start with the quartz layout and so everybody who starts thinking about writing latex in the lecture will realize that the backslash is not that easily reachable and get used to it there are apparently also some hybrid layouts and I don't really know the exact speed of my quartz typing but there's also NeoQuartz which is something that you can try where on layer 1 and 2 all the usual letters are that you are used to from the quartz layout but then all the additional layers with the special symbols they are changed to the Neo2 layout but I use quartz and I tried changing at some point but it really made more problems than it was better and so I didn't do the effort okay one more question that was the backup but I'm still interested and that did you use did you consider using other text set es gibt da auch zum Beispiel Editoren die da yeah I have seen some people that have taken notes for example in markdown there are also editors that allow math-leitag actually math-leitag within markdown and can immediately render that you may also know that from headstock where on one side you have the code and on the other side you see it rendered yeah the problem with a lot of these things is as compared to pure leitag you don't really have all of the possibilities and the possibility to write your own macros in such a manner and I realized that I have not seen any lecture where I had to take notes where there wasn't some symbol that I had to define by hand at some point or some definition that I had done sometime else that I had to reuse it doesn't really happen that one can just use the standard set of leitag and that is enough usually there is a few comments people are thanking you for your presentation I would also like to thank you for that it's pretty crazy what you achieved and our signal angel will be using some of your tricks that's what you want after such a talk isn't it thank you Nick for the talk and now have the Howard News Show with the next at 6 o'clock we have an infrastructure talk and at 7 we have the next news show see you then, bye bye thank you for listening to the translation provided by oscar and she's a pirate


In part one we have learned that our brain is constantly trying to play tricks on us and how we should fight that. We also learned about spatial imaging, ear candy and that we should only vary one component when comparing equipment. You might check out part one if you haven't watched it already. I put a link in the top right corner and in the show notes. The next job is to identify fingerprints or shortcomings in your reference setup. If you can't find any, you are either not a gifted listener or an extremely brilliant set builder. I have never heard a stereo without shortcomings and I would be highly surprised if such a thing would exist. Most likely you have to try again until you come up with one or more shortcomings, things that are not supposed to be there. The difficult thing here is that your brain knows it's listening to a stereo and stereos sound like stereos and not like real sound according to your brain. Let's take one of the most difficult things to get right in a stereo, sibilance control. Many audiophiles take for granted that distorted sibilance is not on par with the real world. Even seasoned listeners tell me that's in the recording when I know it isn't. That's okay for it is rather difficult and often expensive to get it right. So you better learn to live with it. But for argument's sake, let's say that you want to improve sibilance control in your setup, then it would be nice to find out what causes it. The only way to find out is to replace individual components piece by piece and including cables and music files or discs. It's therefore handy to have audiophile friends to exchange equipment and cables with. Friends can also point you to properties of the sound, both positive and negative, that are remarkable. That way you teach each other to listen, and yes, initially you will misinterpret some properties as will your friends. That brings us back to video one. Make sure that no egos get in the way, for that will absolutely lead to errors. As an exercise, connect your smartphone as a source and listen to the changes it causes. Or the old CD player you gave to your son that he no longer uses since it needs those funny silver discs.  Luckily there are alternatives, like structuring the information, and that's what I do when judging equipment. When playing music I scan for all kinds of properties, often one or two properties immediately demand your attention. Note them down and then structurally scan for all other parameters. Again, do not use a limited number of discs, vary the discs you use, but only use discs that you know well. You might check on the following parameters. Tambra. Do all instruments, especially voices, sound natural and free from coloration? Resolution. How well are instruments separated from each other and how well can you hear, for instance, the left and right hand of a solo piano track? How well can you follow a baseline? Spatial imaging. How well is the acoustic space in a recording projected behind and sometimes even outside the loudspeaker? Stereo impression. How well are the instruments placed within that spatial imaging? Are they easily located and do they have their own space in the stereo image, offering a 3D image? Sound balance. How well is the balance between the instruments in the recording? Distortion. Are there instruments that sound distorted? This is often most clear on human voices, brass, glockenspiel, tubular bells and the like. Sibilance control. Sibilance, like sharp s-sounds in vocal music, is difficult to get right. Both vinyl and digital sources can suffer from it, although it's often easier to solve with vinyl by better setting up the tone arm. Noise. Do you hear noise not related to the music playing? Modulation noise. Do you hear noise that is related to the music playing? Microdynamics. This is about hearing dynamic behavior and transients on individual instruments, like discovering a marimba playing in the back of a stereo image, or the tapping of a glass. Finding shortcomings in a stereo is simply put scanning and quantifying the aforementioned parameters. That can only be done if you are fully relaxed and have a clear head. Stress is killing, also for evaluating gear. Alcohol and canine-holding beverages, like indian tonic, should be avoided too. The room you are listening in should have a low noise level. Digital sources vary in output voltage between slightly under two volts to slightly over three volts if it's a single-ended connection. That normally uses RCA connectors. Two balanced outputs will be twice as high in voltage and use XLR connections. With both single-ended and balanced there is a difference between the lowest and the highest voltage of 3.5 dBs. If you don't compensate for that, the loudest sounding setup will sound the best according to your brain. A difference of only one dB might be of influence. Therefore stick a piece of master tape around the volume control and mark the positions. If the amp has a digital readout of the volume setting, that's even simpler. If you are comparing amps, place them next to each other so you can easily swap connections without touching the volume control. Comparing loudspeakers is a lot harder. The tonal balance between loudspeakers can differ greatly and that can have influence on the level measurement. That's the reason I don't use a single frequency but pink noise for SPL measurements. It will take the total sound pressure level into account. Another thing when comparing loudspeakers is acoustic coupling. Never place the speaker pairs next to each other, for then the playing speaker will set a woofer cone and thus the internal air in the neighboring speaker in motion, which will color the sound of the speaker playing. You best place the non-playing speaker away from the playing speaker. The other side of the room is a fair choice. In another room is the best choice. A fairly workable compromise is to short-circuit the terminals of the non-playing speakers. That will limit the movement of the woofers. Depending on the efficiency of the loudspeakers they can differ in loudness and a given power from almost nothing to even 20 dBs or more in extreme cases. You can easily set levels using a sound pressure level meter app on your smartphone. Please don't call that a dB meter. Use the official abbreviation SPL meter. Set the app to slow and A-weighted. Play pink noise and set the volume control for a given level, like 75 dBs SPLA. Then swap the gear you are comparing and do the same. Some apps have pink noise generators built in, but pink noise files are readily available on the internet too, as MP3s, Rouse or YouTube video. Select the sound level you feel comfortable with, but don't go beyond 80 dBs SPLA. You best listen at the position you normally sit when playing music, although it can be interesting to listen at other places in the room too. Of course loudspeaker placement will have a significant effect on the sound quality. Wrongly placed loudspeakers can sound boomy, a harsh midrange and poor to non-existent spatial information. Watch my video loudspeaker placement long version for my two-step approach to loudspeaker placement, the easiest way to set up your loudspeakers properly.  As I've said before, don't use AB switching. You can establish a number of differences that way, like tonal balance, but that is only a part of the possible artefact. Unless there are large differences with other artefacts too, of course.  It therefore is important to listen equally long to both devices on the test. Play a track on setup 1, then do the same on setup 2. While listening scan the earlier mentioned criteria and try to rate each criterion on a scale of five. Best make a scoring table on a notepad. I find the paper one plus pencil the best choice. Do that on as many tracks you can. You might attempt to do a blind test, but that's not always easy. First you need a second person to do the swap, which will make judging for you harder because of the social pressure. But you also have to make sure that there are no clues that give away what is playing, like the sound of the input selector or differences in sound of the CD mechanism. Even the face of the person switching between the two setups might give away some info. In scientific blind test, no one in the room is allowed to know what setup is playing. Most important is you take your time. Spread the evaluation over several sessions on several days, if you can. If not, do one hour sessions with at least 30 minutes breaking between and do as much time not listening to the music. What? I learn a lot about equipment when I have the music at the background volume while reading, playing a game of Solitaire or for instance writing this text. My auditory system is then at rest and only warns me if unusual situations arise. For instance hearing details in a recording I had not heard before or a distorted voice in a recording where it shouldn't be. Or literally when writing this paragraph the fantastic texture of the bass of Way Down Deep by Jennifer Warnes from the album The Hunter. Playing was the fantastic chord Dave and M-scaler combo in my setup one. I'm not sure this works equally good for non-trained listeners, but if it isn't, it's a good reason to start training. As I've tried to indicate by starting with a bit of my history in part one of this video, the ability to judge audio equipment has a lot to do with experience. An experience is practice times time, so the only way to get experience is to start practicing. Not that you have to, if you just want to enjoy the music that's perfectly fine for that is, or at least should be, the goal of audiophile equipment. Let me also stress that all this is my experience, based on what I did in practice and was told by those whose shoulders I am privileged to stand on. Furthermore, I won't claim it's the only way to work. It's just my way of working. Which brings us to the end of this show. As usual, there will be a new video next Friday at 5pm central european time. If you don't want to miss that, subscribe to this channel or follow me on the social media so you will be informed when new videos are out. Help me reach even more people by giving this video a thumb up, or link to this video on the social media. It's much appreciated. Many thanks to those viewers that support this channel financially. It keeps me independent and lets me improve the channel further. If that makes you feel like supporting my work too, the links are in the comments below this video in Youtube. I am Hans Beekhuyzen, thank you for watching and see you in the next show or on theHBproject.com. And whatever you do, enjoy the music.


The House of Squibb, manufacturing chemists of the medical profession since 1858, bring you Academy Award. The pictures, the players, the techniques and skills which have won or been nominated for. The coveted awards granted each year by the Academy of Motion Picture Arts and Sciences to each in his field for outstanding achievement. The House of Squibb, makers of the great family of Squibb medicinal products, brings you the distinguished stars Claire Trevor and Randolph Scott in Stagecoach. The production which in the category of best picture of the year was nominated for the 1939 Academy Award. This is the story of a trip by Stagecoach in the early days of the West. By Stagecoach from Tonto, Arizona to Lord'sburg, Arizona, a few miles today by car or train, an epic journey in those frontier days shortly after the Civil War.  It is mostly though the story of a bad man of the trail and a girl who thought she was too bad to marry him. Never get to drive, Fort. Back the way you've been croak and I figure you're plum scared of Geronimo and his apaches. Well, of course I'm scared of Geronimo. So are you. And if we didn't have all these soldiers riding with us, I'd go right back to Tonto. I've been thinking about you too, Curly. Me? What for? Well, it's right funny you trailing the ring, old kid. I thought he was in the pen. He was. Busted out? Yep. I hear that he was busting to get to Lord'sburg to get even with the plumber boys. But I aim to find the kid and put him back in the pen where he belongs. Hey, ain't that a fella standing along the trail ahead? Yep. Seems to be.  Give me room to swing my gun. Whoa, whoa, there. Wonder who he is. I don't remember no puncher being along this way.  You ought to know him. Hey, pull up careful. He ain't got no horse. He's carrying his saddle in one hand and holding a Winchester in the other. I'm sure glad he ain't Geronimo or the Ringle Kid, that's all. Give me room, buck. It is a Ringle Kid. I'm sure glad it could. What? Hello, kid. Ain't you far from home? You mean prison, don't you, Curly? Well, I didn't expect you to be riding shotgun this trip. Going to Lord'sburg? I figured you'd be in Lord'sburg by this time. Lame horse. Got any room in the coach, buck? Well, I reckon so, Ringle. Then you've got another passenger. Yeah, downright we have. I'll take that Winchester, kid. I ain't going to argue about it, Curly, but I just hate to part with a gun like this. I guess you don't understand, Ringo. You're under arrest. Won't do you no good, a monkey with that rifle, kid. We've got a cavalry escort coming up behind. Well, what do you know? I guess it's all right. Here's the gun, Curly. Thanks. Now, just get in the coach and make yourself to home. Well, why don't you say something?   Well, dawg, come on and hear something that makes sense. I've been peeking down back into the coach and I've seen the Ringo kid make an eyes at Dallas and she's making eyes at him. That's rich. The Ringo kid and Dallas the dance ball gal. Some match. He breaks out of jail and she gets picked out of town. Come on. I help you down, Miss Dallas. Pretty high step. There. Thanks. Oh, just a minute. Yes. I just wanted to thank you for smiling at me in the coach. Smiling at you. Well, that isn't anything. Yes, it is. To a fellow who's been in jail, it is. Well, I appreciate it, Miss Dallas. You see the others, except Doc Boone, they were kind of upish, not that I blame them. Oh, I guess they don't mean to be. Oh, I guess not. Only I... Well, I notice sort of that they acted kind of that way to you too. Oh, well, yes, I guess they did. I didn't mean nothing by what I said. If I said something that offends, I... Well, I'm sorry. I'm not offended. I didn't get a chance to get acquainted with the folks in the stage. You know who they are? Yes. That's Mrs. Mallory standing there. She's on her way to join her husband, Captain Mallory of the Cavalry. You know, Doc.  The dark tall man is Hatfield, the gambler. And the little wheezing man is Mr. Peacock. He's a whiskey salesman. Thanks. I guess that covers everybody, except you. Me? Yes, sure. You're such a pretty gal to be traveling alone. You countin' on meetin' a husband somewhere along the line? Husband? Well, no, I... I hadn't... No, I... I have no husband. Good. I feel better, Dallas. Dallas, mind if I call you that? No. No, I don't mind. Hey, yo! Ringo! Come on in here where I can keep an eye on you. Why, sure, Curly. After you, ma'am. Are you folks doin' here? Howdy, Maggie. Where's the soldiers was to meet us? Ain't no soldiers except those that come with you. Billy and me didn't expect no stagecoach coming through with them apaches, raisin' cane. It was just figurin' on hitchin' up the buckboard and goin' into Tonto where it's safe. You mean there are no troops here? But my husband, Captain Mallory, I was told he was here. He was, dearie. Got orders night before last to join the soldiers at Apache Wells. Well, I guess we gotta turn back. See here, you're the station agent. This coach started for Lord's Burg and it's your duty to get us there. Mercy, mister. I'm just an agent. Ask the driver. If the soldier's gotta go back, we all gotta go back. Um, yes. I think, uh, that is, I feel, uh, we should all go back. I think we can get through all right, Curly. Well, saddle this by boat. Folks, if we push on, we can be in Apache Wells by sundown. Soldiers there will give us an escort as far as the ferry, and then it's only a hootin' a holla into Lord's Burg. Now wait a minute, Curly. We've got four men can handle guns. Five with you, Ringo. Doc Boone can shoot, if sober. As follows, slander, Curly, by when I was in training in 61 to put down the rebellion in the south. Later on, Doc, later on. Now, Mrs. Mallory, I don't aim to put no lady into danger without she boats for it. I've traveled all the way here from Virginia. I'm determined to get to my husband. I won't be separated any longer. And what's your vote, mister? Where's your manners, Curly? Ain't you gonna ask this lady first? Huh? Oh, well, what do you say? What difference does it make? What does it matter? I demand that we go on. I stand on my legal rights. We'll count that as a vote. What do you say, Hatfield? To Lord's Burg. If Mrs. Mallory can go, I can. In fact, it's my duty as a gentleman to protect her. You, Doc! Aye, sir, I'm not only a philosopher. I'm also a fatalist. Somewhere, sometime, there may be the right bullet or the wrong bottle waiting for Josiah Boone. Why worry where or when? Yes or no! Having this wisdom, sir, I have always courted danger. During the late war, when I had the honor, sir, to serve the Union under our great President Abraham Lincoln— Do you wanna go back? No! Mr. Peacock, you! But I, um, I would like to go, brother. I want to reach the bosom of my dear family, but I may never reach the bosom if we go on. Uh, brother, I think it best we should go back to the bosom. I mean, the soldiers. May Ringo and Buck vote to go on, and that settles it. So you better all wash and have a bite to eat, folks. Then we'll hit the trail again. Good. Set right in, folks. It's hot and ready. And another delay. Boy, I could eat a coyote. Later on.  Yeah, Dallas, you're going down where no folks are sitting. Take this chair right by Miss Mallory. Oh, but I— I— Well, thank you. I think, Mrs. Mallory, you— you would find it cooler at the other end of the table, near the window. I'm sure I would. Thank you, Mr. Hetfield. I think I'd find it cooler there, too. Well, it— it looks like I got the plague, don't it? Oh, no. No, it's not you. It's me. Well, I guess you can't break out of prison and enter society the same week.  Thanks again for being kind to me, not moving away like they did. Oh, no. Please. You don't understand. I— Would you have the bread, ma'am? Mrs. Mallory, are you ill? No. It's just— I'll be all right. You're very kind. Why? In the world I live in, one doesn't often see a lady, Mrs. Mallory. But they say you are a gambler. Yes, my dear. I guess I am. Have you ever been to Virginia, Mr. Hetfield? I had the honor of being in your father's regiment. Oh? But I don't seem to recall the name of Hetfield. It's what I'm called. Everybody up. Come on, folks. Next stop, Apache Wells. Horses. You yell. Shucks, I know it. I gotta yell something, don't I? You want them to think we're stopping for Indians? Get the folks to bat, Chris, while we change horses. We're pushing right through to Lord'sburg. Are you coming without the soldiers? Sure, we wasn't scared. Never seen an Apache, did we, Curly? Where's the cavalry, Chris? Yeah, where is the soldiers? There is no soldier. The soldiers are gone. My husband. Where's Captain Mallory? Where is he? You, his wife, I think. Yes, where is he? Did he go with his men? Yes, senor. A little, what you call it, skirmish with the Apaches last night, the soldiers take Captain Mallory to Lord'sburg. I think he gets hurt. Hurt? Bad. Yes. Mrs. Mallory, let me. Mrs. Mallory, she's faint. Carrier should be all right. Get some water, somebody. Take her in, Curly. Put her to bed. To bed? Well, we gotta get hitched and on the trail for Lord'sburg. Put that woman to bed. If he can't take this bottle of whiskey. Guard it with your life until I'm finished. Here, I got the water, Curly. Take the water in the kitchen with Dallas. Boil it. Boil plenty of it. Boil it? But, doc, it's about 200 pounds. Boil it? But, doc, it's about 200 in the shade right now. I said boil water. Plenty of water.  What are you trying to do? I've got to get to Lord'sburg. You'll get to Lord'sburg when that woman has fit the travel again. Again? Well, what's the matter with her? She's gonna have a baby. Now, come on. Help get me sober. Before continuing with the second part of Academy Award, I'd like to tell you about one member of the great family of squib products. I'd like to tell you why it is you get so much satisfaction out of every tube of squib dental cream. Why, when you use squib dental cream, you can taste, feel, and see the refreshing difference. You see, squib dental cream is produced with extraordinary care. Its purity and effectiveness are guaranteed by more than 100 separate tests. And the delightful minty flavor of squib dental cream is so mouth-refreshing. The active ingredient in pure squib dental cream is one of the safest, softest, yet most effective polishing agents known to dental science. For in dental cream, as in life-saving drugs, squib has only one goal, perfection. So remember, next time, to ask for squib dental cream, taste, feel, and see the refreshing difference. In just a moment, we'll present the second part of Stagecoach. But first, we want to thank United Artists and Walter Wanger for making this story available. You'll be interested to know that Walter Wanger's next production is Night in Paradise, which can soon be seen in your local theater. And now the House of Squib presents Part Two of Academy Award, starring Claire Trevor as Dallas, and Randolph Scott as the Ringo Kid in Stagecoach. What was that? Just an old coyote hat field. That was no coyote? Listen. That wasn't no coyote. What? It's a baby. Then that's enough of a card planned for me tonight. Looks like Doc brought it off all right. Good boy, Doc. Well? It's a girl. A girl? Well, three cheers for old Doc Boone. Hup, hup! Quiet. Mrs. Mallory must not be disturbed. How is Mrs. Mallory? She's gonna be all right. Well, doggone. And I thought that little critter was a coyote howlin'. Who's there?  The patches like to sneak up and pick off straight. Oh. I, uh... I watched you with that baby. You look... Well, nice. Oh, uh... You were visiting in Lodzburg? No, I... I have friends there. Look, why don't you escape, Ringo? Why don't you escape? I aim to, Miss Dallas, in Lodzburg. Why Lodzburg? Why don't you get over the border? My father and brother were shot down by the plumbers. I guess you don't know how it feels to lose your own folks that way. My people were killed by the Indians. I was just a kid. There was a massacre in the Superstition Mountains. That's tough on a girl. It's a hard country. You have to live. No matter what happens. That's it. Look, Dallas. You've got no folks, neither have I. Maybe I'm crazy to ask you, but... Well, I still got a ranch across the border. It's a nice place. Trees, grass, a house half built. You see, I'm asking. Well, what I mean is... A man could live there, and a woman. Oh, I guess I'm crazy being so... So close to you like this. But you don't know me. You don't know who I am. What I am. I know all I want to know. You're the kind of a girl a man wants to marry. What you doing out here, kid? Oh, it's you, Dallas. You come along, kid. Stick close to the reservation. Time we've bet it down, too. We've got to hit the trail come on and early. Geronimo or no Geronimo. Good morning, Dallas. Hello, Doc. Good morning. I, uh... You stayed up all night with my patient. Thanks. I slept some in the rock. Hey, holly! Everybody up! Get your breakfast, folks! The stagecoach is leaving on its last lap! Next stop, Wardsburg! Everybody up! It's about time. Good morning. Good morning. I laid awake most of the night, wondering what you'd have said if Curly hadn't busted in. You didn't answer what I asked you last night. We can go. Why don't you escape? There's a horse out there on the corral. Curly won't go after you. He can't leave the passengers in this fix. But I got to go to Wardsburg. Won't you go to my ranch and wait for me? Wait for a dead man. You haven't got a chance and you know it. It was three against one when the plumbers swore you killed the foreman. It'll be three against one in Wardsburg. There's some things a man just can't run away from. How can you talk about your life and my life when you're throwing him away? What do you want me to do? Would it make us any happier if Luke Plummer was dead? One of his brothers would be after you with a gun. We'd never be safe. I don't want that kind of life, Ringo. I don't see what else I can do. Go now. Get away. Forget Wardsburg. Forget the plumbers. Make for the border and I'll come. You mean that? I do, I do. Won't you come along with me? I can't leave Mrs. Mallory and her baby. I'll come to you from Wardsburg. I swear it. I ought to have my rifle.  Now go on, Ringo. Saddle up and ride. Ride for the border. Ringo!  Ringo! Ride! Ride! Don't stop now!  You had a chance. Curly couldn't have caught you. I couldn't leave you now, Dallas. Give me your hand, kid. I'm putting the irons on you this time. Don't worry, I'm not running away. I'll say you ain't. Look at them hills. Smoke sickness. Listen. Boredrums. Geronimo's are patches. Right. Waitin'. Come on. Doin' somethin' mighty foolhardy. Tryin' to run through these hills. And them for Indians. We don't know they are yet. Keep runnin'.  He's mighty handy with a gun. You drive them horses, so I'll worry about the kid. Right, all right. Come on, boys.  We gotta run for it now. I've ammunition. So am I, Doc. I've got three rounds. Save him. Dallas, haven't you got a smile for me? Oh, sure, Ringo. Oh, sure. Thanks. Ringo! Boxhead horse! Right. So long, Dallas. Wait! Wait, Dr. Harris? Yeah, what, ma'am? A mule bull. A cavalry. Let me see. She's right. Soldiers from Lord'sburg. Ringo! Oh, that buck, you all right? She's the end of the line.  Get a stretcher. Take it easy. We've got a dead man in there, too. Where's Mrs. Mallory? She's all right. Well, tell her our husband, Captain Mallory, is out of danger. Tell the captain he ain't. He's a papa. Well, so long, Dallas. So long, boys. Well, Curly, we're in Lord'sburg. Yeah, kid, this is it. Could you spare me an hour? I don't know, kid. My will still goes, Curly. I'll be back in an hour. All right, kid, I'll trust you. Could I take my gun? Sure, why not? It ain't loaded. I borrowed three shells from Gatewood. Three? One for each of the plumber boys, eh? Yes, buck, one for each of them. You're out on parole for an hour, Ringo. That's all I want to know about it. One hour. Wait, Dallas. Ain't you walking the wrong way? This way is the bad side of town. The dance halls and the... Dallas, wait. Let go. Let go of me. I told you not to follow me. But you can't go down there. That's where I'm going. I ask you to marry me. I'll never forget you asked me, Ringo, at something. See them scars and cuffs. Scars wear off, Dallas. I ain't gonna give you a chance to forget me. No, please, Ringo. Let me go now. Ringo, listen. They are waiting around the town in the road. Thanks, Ringo. Thanks. I'll be ready. No, Ringo, no. Wait for me here, Dallas. Wait for me right here. I'll be back. Ringo, come back. Sit on this buck bar. Waiting for Ringo. That's gonna be some weight with them three plumber brothers laying for him three against one.  She's waiting, ain't she? Dallas? Well, heck, Curly, she's gotta wait. She's in law. Three of them. Plumbers. And big shadows, Curly.  I'm looking for the other shadow. There it is. That's him, Curly, that tall shadow. Straight as an arrow. He said to wait. Yeah. I'll be waiting forever now. What chance would he have? Dallas, I told you I'd be back for a little while. Ringo, you bloody... Get up here, Dallas, on this wagon. You gotta drive. She can stay with me a while, Curly. Yeah, for a little while. Let her drive. You nurse that on. Thanks. Got a good hold on them, Rains Dallas? Yes, Curly. I've got him. All right, then. Yeah! Yeah! It's the idea of making them horses run away.  Them nags won't stop till that buck borders over the border. But you'll let Ringo get away. Yeah, Buck. I guess I did it that. Now, wasn't that disgraceful careless?  We're now looking down into a room where figures, gowned and masked in spotless white, are working under the brilliant light of huge sterilizing lamps. At first glance, you might well believe yourself to be in the operating room of a modern hospital. But what you're actually seeing is one of the rooms at the squib laboratories where products such as influenza virus vaccine or penicillin are packed. The most sterile conditions possible are always maintained there. Even the air is sterilized. No operating room anywhere is more scientifically safeguarded against contamination. It's just one example of the endless precautions taken by the House of Squib to ensure the uniformity, purity, and efficacy of all the many squib products. Through such responsible service, in the cause of human health, Squib has earned its worldwide reputation as a name you can trust. Next week, another great picture of the House of Squib will present Academy Award-starring Ronald Coleman in If I Were King. Stagecoach was written for radio by Frank Wilson with an original musical score composed and conducted by Lee Stevens, our producer-director as D. Engelbach. Randolph Scott, whom you enjoyed his ringo in today's performance, can now be seen in RKO's Batman's Territory. Claire Trevor, who played Dallas, will soon be seen in the RKO picture at Cracow. This is Hugh Brundage bidding you goodnight until next week at the same time when you are invited to listen again to Academy Award presented by the House of Squib, a name you can trust. This is CBS, the Columbia Broadcasting System.


Hello, my name is Sebastian Lord and I'm happy to present secure software leasing without assumptions in the context of the theory of cryptography conference or TCC 2021. This is joint work with my wonderful co-authors and broadband Stacy Jeffrey, support the Potter and Arthi Sundara. Let's jump right into it. So one of my main interests in quantum cryptography is where we can apply the no cloning principle to achieve things that would otherwise be impossible using only classical tools. So simply, the no cloning principle states that it is impossible to create perfect copies of arbitrary quantum states. And this is the pillar of many quantum cryptographic primitives that achieve things that would be impossible with only classical means. And the idea here is that the no cloning principle is quite a quantum phenomenon in the classical setting, adversaries and eavesdroppers and any party can just keep copies of classical information that is exchanged back and forth. This is not quite true in the quantum setting. And this gives rise to a whole lot of unclonable cryptography, some of which I'm sure you've already heard of. Perhaps the most famous examples are unclonable tokens. So unclonable tokens are essentially quantum states that contain no meaningful information, just enough so that a receiver can either accept or reject the token. We can also talk about unclonable information. These are encryption like schemes that achieve some extra security notion where this extra security notion is tied into the no cloning principle. This is something that myself and some of my colleagues are quite interested in and we have some previous work on things like unclonable encryption and encryption of a certified deletion. We also have unclonable functionalities and that's really the topic of this talk. And in this talk, we're going to cover two different types of unclonable functionalities. We're going to talk about copy protection, as well as secure software leasing. And one of the ideas that we're trying to promote here is that all of these three notions can be seen as part of a hierarchy, where at the top of the hierarchy you have the functionalities, followed by unclonable information, followed by unclonable token. The idea being that at every level of the hierarchy, these are more and more complex things, if you will, that are rendered unclonable by using the no cloning principle. Okay, so where does the story of unclonable functionalities begin? Well, it begins with a question by Scott Aronson in 2009. This question is quite similar. It asks, can quantum states be used as copy protected programs, which let the user evaluate some function F, but not create more programs for F. So let's sketch out the idea that's wanted here. So what's the basic idea behind copy protection? Well, we're going to have a pair of procedures protect a novel, such that we can feed some function F taken from a larger family of functions into the protection procedure. This is going to yield some quantum state row F and row F can be used in the evaluation procedure with an input X to produce the output of the function F of X. There's been a lot of recent activity, right? Aronson asked this question in 2009, and for about 10 years, there hasn't been a whole lot of progress on the question. But over the past two years, there's been multiple different works, multiple different publication, including other work that will be presented at this conference. I want to highlight at this point that all these other works, they use either some standard assumptions, right, we're talking one way functions or things like that, or quantum oracles or set up assumptions to achieve the security of their protocols. This is where our contribution comes in. So the main contribution in this work is that we construct a secure software leasing scheme specifically for point functions, which is provably secure without any assumptions at all and against unbounded adversaries. So our construction can be instantiated by any total authentication scheme. We'll get into those details in a bit. And we obtain our secure software leasing scheme by passing via this novel security notion of honest malicious copy protection. So we're going to define this security notion, we're going to show how we achieve it. If we were to sketch out the results of this work and look at it like this, you take a total authentication scheme, you use this to construct a copy and honest malicious copy protection scheme for point functions. We then show that honest malicious copy protection for point function implies secure software leasing for point functions. And I want to highlight this result by Colledangelo Mayans and Premba, which states that if you have SSL for point functions, you can also obtain SSL for compute and compare functions. And our construction follows through. Let's formally define copy protection. So as mentioned, we're going to start off with a pair of procedures protected about, and this is going to be a copy protection scheme for a certain family of circuits. Now throughout the talk, we go back and forth between functions and circuits. It's not particularly important for this work. Formally, the definitions are given at the level of circuits, but for the level of this talk, it's easier to reset about functions at times. So the security of our scheme is going to be parameterized by a bunch of different distributions. And this starts off with the distribution D on the family of circuits which we are copy protecting, as well as a set of distribution on pairs of inputs. There's an inputs to the circuit, and every single circuit C has its particular distribution on pairs of inputs to see. And we're going to analyze the security via a game that's going to be played by a referee against a collaborating pirates and two evaluators. So the pirate and two evaluators get to set a strategy ahead of time, but the communication that they have during the run of the game is going to be quite limited. So let's put up our referee, let's put up our pirate and our two malicious evaluators. I want to highlight here that the two evaluators are distinct, they can behave in completely different ways. The game starts off with the referee sampling a circuit C, according to the distribution D, and producing the copy protected program row that results from protecting the circuit C. The state row is handed off to the pirate who can do arbitrary computation. But at the end of this, the pirate has to hand off one register to malicious evaluator zero, and one register to malicious evaluator one. Once the program state is split between both evaluators, the referee will sample two inputs to the circuit X zero and X one, hand off X zero to evaluator zero, hand off X one to evaluator one, and both evaluators attempt to compute the value of C X for their respective X. So they output some Y zero Y one, and they win if and only if both correctly compute the value of the circuit on their inputs. Normally we're going to say that the scheme is epsilon copy protecting if the probability that both evaluators correctly outputs is at most some trivial guessing probability plus epsilon. What is this trivial guessing probability comes comes from. Well, there's one attack that we can't prevent the pirates and the malicious evaluators of implementing. And this is simply the attack where the pirate hands off the program completely unchanged to one evaluator, and the other evaluator guesses their value of Y simply based on their value of X, and we optimize over this gets into obtain the trivial guessing probability. So that was copy protection, but we mentioned that we're going to achieve honest malicious copy protection which is a slightly weaker version of this more general idea. So, I want to highlight that in the game that we just studied malicious evaluators are completely unconstrained, we have no guarantees on their behavior, they can do whatever they want. In this malicious setting, we're going to force one of the evaluators to behave honestly. So if we put up the same diagram as last slide, it's going to look quite similar with the only difference being that one of the evaluators must be made honestly. They must use the evaluation procedure that is prescribed by the copy protection scheme. In addition to this, the setup is essentially the same. We're going to say that the scheme is epsilon honest malicious copy protected, if the probability that both the honest and malicious evaluator correctly compute the value of the circuit on their input is at most some trivial guessing probability. So we're going to call this epsilon where the trivial guessing probability follows from simply giving the unchanged program state to the honest evaluator, and having the malicious evaluator guess the possible outcome based only on x one. Okay. So we're going to achieve this idea of honest malicious copy protection by using quantum authentication. So let's talk about the general idea behind quantum authentication. This syntax, a quantum authentication scheme for some particular space M is just a collection of pairs of quantum channels authenticate and verify indexed by keys K. And they satisfy this correctness guarantee that if you verify an authenticated state by using the correct key, you get precisely that state that same state back, as well as a flag qubit in the a register. The register is spanned by either the a state or our state for accept or reject. Now security is a bit more technical to define. But kind of the intuitive idea that you would want to have in head is that if you had some attack that interacted with the state between the authentication and verification procedure. And make sure that you never output the reject flag if you don't obtain the initial state that now this is not a formal definition and in fact there might be some issues in formalizing precisely this, but it's a bit the intuition that you would want frequent authentication But we're going to need a more precise security definition and the security notion that we're going to pick among the various ones in the literature is total authentication. And this is a notion that was first introduced in 2017. To properly talk about total authentication, we need a slight variation on the verification map, which is this verification with the overline, and this is simply verification conditioned on acceptance. So we check to make sure that the flag is in the accepts state and we just reject if it is, we just reject the state if it's in the reject flag. So, I want to highlight that this is not a trace preserving math. The trace of the state following this overline verification is precisely the probability that accepts. And what we're going to do is a bit of an ideal versus real set. So, in the real setting, some adversary can pick a state row that's going to be authenticated, as well as living on some memory register that the university holds. If the message register gets authenticated, the adversary can attack both the authenticated states and interact based on their memory register, followed by verification and once again we're going to condition on acceptance by this overline. So we get some state Sigma in the real setting that depends on a key K. But what's an ideal adversary for quantum authentication. Well, we could think that the ideal adversary is an adversary that just does not interact with the authenticated state. So, here we have an ideal it's a bursary side that simply interacts on their own memory register they cannot touch the authenticated state between the authentication and verification. And note that this authentication scheme is epsilon secure if for all state Sigma. Sorry, if for all initial states row, the final states in both of these dashed red boxes are epsilon close and trace distance and note that this includes the key K. I want to highlight here that in the ideal scenario the adversary and their memory register Z they have no information on the key that is used right they don't actually find a way to interact with the key. So how can we use a total quantum authentication scheme to construct a copy protection scheme for point functions. So let's recall that a point function is a function that takes us input a bit string of like that and outputs a single bit. Now, every point function is characterized by precisely one bit string. It's point, we're going to denote it P, and the function is such that it outputs one if and only if the argument is its point. So, now we're going to take some epsilon total authentication scheme we're going to fix an arbitrary state psi on the message space. The idea is to build on this correspondence that we can have between inputs to the point function and keys to the authentication scheme. So our protection algorithm, our protection procedure on input of a point function delta P is simply going to output the authentication of the fixed state using the point as the key. So, if we authenticate. Sorry, if we protect using authenticate, we're going to evaluate using verification. If we have a candidate program Sigma and some argument X, our evaluation procedure is simply going to verify Sigma using X as the key. The evaluation procedure that outputs one if and only if the verification accepts. So, ideally, we would achieve correctness in the following way we would say that we have an data correct scheme if for all possible arguments X and all possible point functions delta P. The probability over the randomness of the evaluation and protection procedure that you obtained the correct outcome is greater or equal to one minus eight. Unfortunately, we don't achieve the above correctness, but instead we're going to have correctness with respect to certain distributions. So what do we mean by this, we mean that we're going to define and achieve a correctness with respect to family of distributions index by put that by potential functions. More precisely, for all possible point functions, the probability that the evaluation correctly outputs taken over the randomness of the evaluation protection procedure, as well as the sampling of the input is at least one minus eight. We don't necessarily have correctness for all possible inputs. We obtained correctness averaged or taken out on. Sorry, we obtained correctness with probability over the possible inputs. So, let's bring up the scheme here so recall that we protect by authenticating and evaluate by verifying. So, we're going to show correctness with respect to a very specific distribution. This is the distribution that so sorry, so the distribution is indexed by the point function delta P. And for every possible bit string, it's going to be P with probability one half and not P with probability one half and in this case it is sample uniformly at random over all possible strings that are not P to properly show correctness we actually show this following theorem which states that for any epsilon total authentication scheme for any state row. If you simply random key K, the probability that you accept is at most to to the epsilon. So the theorem follows from the security of the authentication scheme, you can kind of be the argument essentially says that if there was a state that was excited that was accepted with higher probability. You could use the state to construct an attack against the authentication verification scheme. So, this is the authentication scheme for all points P. We have that we correctly evaluate on the point P with probability one, and this theorem will allow us to make a statement for what happens when you try to evaluate with the wrong key. You combine all of the above, and you show that when you start with an epsilon total authentication scheme the probability that you correctly evaluate is at least one minus epsilon. So let's go on to the honest malicious security. Let's refresh our memory just a bit. So, our scheme is here. Once again we protect by authenticating and we evaluate by verifying. More precisely, we're going to prove security when depth one the point function is sampled uniformly at random from all possible point functions and where each challenge is sampled according to this distribution that is P with probability one half and not P with probability two challenges are going to be sampled independently from each other. So let's recall the security games so we have our referee our pirate and both evaluators, and we check whether or not the evaluators correctly compute the value of the function. Okay. So, let's sketch our proof of security. The correspondence between the honest evaluator correctly evaluating Delta P on the point P with accepting authenticated state. And we recall from total authentication that conditioned on acceptance, the attacker will know essentially nothing on the key. Now we play this correspondence more we say that Oh the authentication key actually corresponds to the copy protected function, the authentication attack corresponds to the copy protection adversaries. The conditioned on acceptance the attacker knows essentially nothing on the key they know essentially nothing on the function on the point function is copy protected. That's going to limit their ability to correctly compute the circuit. Right, so if the honest evaluator is correct that the malicious evaluator knows essentially nothing on the point of the point function. So let's analyze the case for the honest evaluator is challenged with something that is not the point of the point function that is authenticated, but we leave that for the paper. For me the theorem that we show is that with this scheme and these distributions, the probability that both that the adversaries when is that most this trivial guessing probability, and this fairly nice function of epsilon. We also show that the trivial guessing probability in this case is precisely one. We've obtained a scheme for copy protecting point functions in the honest malicious setting. Let's finally talk about secure software. So secure software leasing is similar to copy protection in the sense that it prevents copying of programs, but it is a bit different in the sense that there will be no second evaluation, we're going to have a verification procedure instead. So security is also parameterized by distribution over circuits and inputs, much in the same way that copy protection was. So let's sketch this SSL game. So we're going to have a referee and a pirate. In this case the pirate is also going to play the role of the single evaluator. There's no second evaluator as previously mentioned. The referee is going to sample a circuit see according to the distribution D produce some state row that essentially includes the circuit and that state row off to the pirate. The pirate does some computation that can hold on to some quantum information, but eventually they have to return some state signal to the referee. The referee will then verify the state sigma and either accept the return or rejected. So assuming they accept they're going to sample some argument X, according to the distribution TC that can depend on the circuit C, hand X off to the pirate, and the pirate wins if and only if they correctly compute the value of the function on X. Very similarly we're going to say that the scheme is epsilon secure if the probability that the referee accepts and that the pirate correctly computes the outcome is at most the trivial guessing probability plus epsilon. And finally we emphasize that in this setting the pirate can evaluate maliciously so we don't control any of the computation of the pirate does. So how do we obtain secure software leasing from honest malicious copy protection. Well the idea is quite simple, you can verify a return program by honestly evaluating it on an input. The protection and evaluation procedures in the setting are unchanged we just construct the verify from the honest evaluation right so how do you verify on input of some circuit C and a candidate program sigma right that the pirate claims. You sample some argument X prime, according to some distribution T prime C, you compute, and you verify whether or not this is the correct outcome. If you plug this into the game you get this figure here where we just kind of expand a verification procedure to include, and you see that this essentially simulates the honest evaluator of the honest malicious copy protection game. The reason that we show is that if the copy protection scheme is epsilon honest malicious secure with respect to some distribution D, and this distribution on challenges. Then the derived SSL scheme is going to be epsilon secure with respect to the same distribution on the circuits, and just the singular distribution on the challenges to the pirate. So in conclusion, what do we have as results in this work well we define and achieve honest malicious copy protection with no assumptions, I also want to put up this figure here that kind of sketches how we do this. We show that honest malicious copy protection yields SSL. And we can contrast this work with other works where we do not need any assumptions we have no setups and no oracles. Finally, but kind of the trade off here is that for copy protection we only consider a restricted class of adversaries right we have honest malicious copy protection which is a bit weaker than the more general malicious malicious copy copy protection if you will. So there's two main open questions for future work. First of all, can we improve the correctness of our scheme right so currently we have correctness over with a probability over possible inputs we would like to have correctness for all possible inputs. And perhaps the main question is, can we achieve copy protection against multiple to malicious evaluators without any assumptions at all. And I think this is a question that is gathering quite a lot of interest in the field right now. And with that, thank you very much.