Contributor analysis

Video in TIB AV-Portal: Contributor analysis

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Contributor analysis
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Contributor analysis is a simple cryptanalysis technique which allows detecting and attacking blatantly broken cryptographic algorithms and implementations. Although the technique is inspired by the techniques employed by algebraic approaches it aims at being much simpler to understand and reason with, making it possible not only to automate the testing but also to even run tests using pen and paper. In this talk we will introduce the participants to this technique, explain briefly the theoretic principles that make it work and how it relates to algebraic cryptanalysis and then explain how to handle contributor lists with different common operations. We will explain how these lists can be used to mount an attack therefore proving why a succesfully attacked cipher can be considered broken. Finally we will show some simple examples of ciphers affected by these techniques. No mathematical nor cryptographical knowledge is needed to follow this talk although some programming or computer architecture knowledge is recommended.
Constraint (mathematics) Computer animation Computer engineering Information security
Software developer Mathematical analysis Sound effect
Implementation Group action Beat (acoustics) State of matter Code View (database) 1 (number) Student's t-test Parameter (computer programming) Number Revision control Operator (mathematics) Cuboid Energy level Endliche Modelltheorie Data structure Physical system Key (cryptography) Information Mapping Gamma function Cellular automaton Forcing (mathematics) Poisson-Klammer Electronic mailing list Mathematical analysis Data storage device Sampling (statistics) Sound effect Total S.A. Bit Data mining Digital photography Personal digital assistant output Speech synthesis Right angle Quicksort Coefficient Surjective function
Divisor Multiplication sign Physical law Electronic mailing list Bit Parameter (computer programming) Compiler Impulse response Personal digital assistant Analogy output Right angle Position operator
Beat (acoustics) Implementation Knowledge base Forcing (mathematics) Software developer Execution unit Combinational logic 1 (number) Materialization (paranormal) Electronic mailing list Plastikkarte Number Computer animation output Website Right angle Collision Quicksort Pole (complex analysis) Library (computing)
Decipherment Computer animation State of matter output Bit Social class
Decipherment Beat (acoustics) Process (computing) Computer animation Personal digital assistant Similarity (geometry) output Bit Musical ensemble Number
Computer animation State of matter Mereology Number
Addition Implementation Computer animation Personal digital assistant Order (biology) 1 (number) Family Product (business)
Revision control Category of being Implementation Loop (music) Computer animation State of matter Set (mathematics) Quicksort Funktionalanalysis Number
Computer animation State of matter Personal digital assistant Bit Number
Decipherment Word Clique-width Computer animation Optimization problem Mixed reality Multiplication sign Ideal (ethics) Energy level Quicksort Substitute good
Beat (acoustics) Computer animation Weight Mixed reality Set (mathematics) output Bit Power (physics)
Decipherment Pairwise comparison Default (computer science) Computer animation Information State of matter Personal digital assistant Single-precision floating-point format Mathematical analysis output Bit Twitter
Dataflow Presentation of a group Beat (acoustics) Group action Digital electronics Computer file 1 (number) Set (mathematics) Water vapor Food energy Cryptanalysis Neuroinformatik Number Representation (politics) Pairwise comparison Sampling (statistics) Mathematical analysis Content (media) Planning Decipherment Word Personal digital assistant Universe (mathematics) Order (biology) Formal grammar output Quicksort
Computer animation Multiplication sign
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OK so my name is said Francisco last year Laureano about its available remain and this if you constraints and so please chemical make and there well I have been working security all 11 years by now why is that with 17 the and I'm a computer engineer and they're allowed that's like in
all things that you put on the wall and you forget about them I'm a city at the height of the development of an idea you could start to the and was knowing what extend does that so well in of hold
me now we're going to introduce you to effect analysis I mean not meant
so this is playing what's confusion and and what's the solution uh to both concepts waiting till you set by Michael someone in 1945 and there you might not realize it but they're they're basically the base below most I'll keep Dorothy coatings for the use of nowadays uh for example IOC's assignment to have both good and with the force so was this coefficient is basically deep that the siphoned have to hide out the relationship between plain text and the text based upon the key that you provided and the fusion and other side which is what we're going to focus on is that each single input the that you provide the safer so the effect each single both will be of siphons because otherwise you can try to focus on 2 speech that have affected by less inputs and then you can try to create 2 speeds and use the information you photos of onto speeds in other productive once uh fine it was as I do not know what level you had they could not be able to see it because this is really the system like my way OK so what is the idea there we want to reproduce the Qaddafi columns of for example die 1 implementation of Fiesole south Atlantique total when the whatever but instead of handing called and operations have going to try to see hold the operations like makes clear that the different inputs that we are providing so that's what we're focusing on the and so how can we not the basins you know that to make that happen well 1st we have the concept of a black so students in books of brackets books the ascendance books on also additional books on which we know which is the gamma mapping at this is broadly is something that stores and the ample people that has been doing different separate analysis so basically would have liked and beats a simple and beautiful pulled and we will assume that this of the input provided to and bits of tilt tools so for every single could be used as a lawyer for a missing single complete we will make the only on all of these all often missing and incomplete we have have to be twice not which is was totally trivial i mean values flipping every single bit that is no gross dependency so built with list of not is the same as the input list I'm or X we only will they interacted with Bessel beat so we use make their we're of both come through list uh seats add a lot more complicated the view on have a constant on perceived parameter so what we will do is just the specter that analysis of the 1st input blood all ports and that will lead because we note that they the 1st the input will be in 1 of 2 possible for systems the strength of its uh for the cells we can spread from Ellis beastliness bees and the cilia familiar with what we got the score book The is that the pig loading that you use of the schools when you have to like at the let's numbers so you start having the 1st the heats up that on the right and then you might have a credit that also play 2nd he'd group of the hits and you add them so if you understand the and you understand why if we 1st will take tell him of of the 1st 2 years and then we propose a that that's scattered to the 2nd group of the use that would provide a conduit and leads to the fair and so on so structures separating appeared in much the same because when we has been offered that as a we would lock complement of 2 so it's and not of the open and and we are sort 1 at the end so that some of the sample and then we'll go on a little east and so we will use the tool to sameAs would have these and and provided from right to left the modifications still the same would provide from kind of the delayed to from right to left as we use it to 1 school most animal tended to match so for now we have to use a black his books so at the museum's uh lately you will not see many models and many revisions and most of them all as you will see Michael was of 2 which you bump on the things that go on by quite answer there might by twice and and there was a like this books which is the to some book you can find for example on mines and this case what we can try to lose state to find out if there is some beats that dominant country with 2 on a specific code would be that this is usually the case so on this books it's like the ones that you set for the target because they get us boxes have 256 bits of input but they have 6 sorry they have 8 bits of input and they have 16 bits of old World so let's see if we can optimize sitting
in that this so funny it's a bit confusing and but now it's hopefully going to be a set so big white and my if
we lobbied waste bound by a constant and it's really simple we used cleared out the lists where they beat the Seidel because we know that this week is going to be Seidel really with a bit ways all of this is that the same we will lead to be it's worth to beat someone like twice x a we used copy the least we noted the constant the too some updates basically we use to see if the rotating inputs which makes things a lot easier if the compiler to law was although it approach item ITiCSE invites seeds we use have to move to the right and then copied the most significant if b is going through the list policing of position we have worked see dates of a constant analogs have been sold for now we will use use the union of factor but that impulse for the 2nd parameter would it be cases where they can be replaced by 6 Summary sense and as you can believe you out that this is the last seed lot of work left to do I
mean they at the stage that the developing pollen on on April and was highest work for time so I the half that much time for this stuff so this gold now for the good
but I mean if we wanted to decipher once we know that there is at least 1 0 could be it that has less inputs and in this country will from the input needs exist on their site for the we would use the right to brute force there the country dose of that single beat and active out which of 2 combinations of contributors had actually collide once uh from the diuretic approach this means that you have broken the safer because you comfy without a new country without which said at the correct inputs using the less than 2 to the number of a immortality of course if we have like a beat that has 127 conjugal dose of 128 with this kind of solves the problem by hey is Roque but in knowledge bases whatever sigh these out fully broken you will find that maybe 1 has 1 or 2 be is that that will do with the poodle and those are the ones that basically that so well now is when we call Faraci polemic the now is when things that are going wrong so let's hope I'll think they could be so hopefully this will work as a and let's move his work on here and this makes use of units so that is I developer the smart Python library that they implement small most of the silence in which you can find them and we still about materials the so 1st we need to import implementation of tolerance which I'm going to do old ways on let's see copied 1 based so for example here you can see that they extort is basically they conclusion of data about mission
of the list of missing a beat on the real data is the and well it's not something has to set a complicated so now we have fair for example there there's Seyfert that we haven't implemented which is a simple exorcise the which you have guys have broadly familiar with the I hope so as you can see believing that we are doing his 1st we annotate their lists of the people's and then here you will concede that we used to take sort of walking poles and then we let alone that is sort of takes
so if we go and generate the state and then we paint to called for by the state you fancy whole basically with fine that they're bit Seidel class to go to those which are uh input CEO and Wunsiedel week 1 has to go do those that that's 1 and 1 1 there be 2 has 0 2 I 1 tools the the silphium 1 the so by now I mean even if you look at all of the and you think that using an Excel sigh face acute you should be able to fewer out that it's not that that delete this if you do that that thing is going you it's only 2 reads for inducing a local greedy so missile for something kind a slightly more that 1 advances in so you can understand that the signaling in the on
the yeah I for look to the find decipher so this is the which US of probably as a familiar with it's basically
having a constant tool no and now we use the safe so the complete and they the OK
so as you can see here we can see that there is less significant beats which in our case beats No. 7 only has 1 can do with them but produces from speed 7 of people see on 1 bit number 6 applet has to do with the from it's 6 and 7 . 0 on 1 and it keeps increasing as we go to the most significant the feature so in this case he would trade to approach the of decipher we would 1st try to break out beta number 7 and then with the was we get from the number 7 that the considered valid inputs will to beats number seeks and then with this from that to be the 5 and so on uh or wealth process simple siphon use that to find out which is the constant by having to seems to bring the expected so far I'm trying to make it simple so so you can understand what they went home on so now we're going to do what I had a similar take oxoacids siphon with fencing around so you can see that there that actually can music with some slightly more there was sigh 1st and then OK
so as you can see now it's a lot more complicated to focus more on when I was doing to them with smaller than uh smallest streaming was a lot easier but
all and then OK so as you can see basically would have a lot of country will despite the latent members of the siphon about it legal to state number 1 we can see that the number of country will discuss user significantly I mean we have some parts where would have 9 7 5 and frequently with those which is out of bite on be number 3 so to
set the beach on which we will instead focus in that that in order to continue calling for the more complicated ones and now we are going to go
for well day-earlier have the stuff uh I mean I have so you
hope to hold if you have 1 product and you have family about it then you have to write it that's why want to switch to that that signal addition so now I'm going to take a so you don't 1 I think you should be able to the by now I mean you have learnt everything you need so they're think case and have an implementation
of the 1st version of the US siphon which is the 1 that motivated well motivated me to start doing that if the set
as you can see it's not very complicated it's so bad pretty much like says that basically we would have a loop on which we will use change the state number for which would be that there can be function of a estates fallecido 12 was constant number 7 and as you can see it's basically sort of outcast 216 is what they call the the two-pass 252 at 60 coming this is pretty much have to follow but if you use this implementation replacing x or 16 . 16 a CD that might the property implementation of discriminative you will get exactly the same results as if you run but and which I hope you never have to but so for those of you that don't know big a sense of where that there transplantable sector and when he's not his very interesting ideas at this from the and so well as you can
see here we can that we have not so in is the onto does because in some cases it's often a huge and he would have liked to 128 255 so it would be the fun have to understand but here we can see that for example for the state the their state number 14 bit number 15 we only have 1 country will and
here we have 2 3 5 6 and 7 that is happily whitetail
you know that that you set the evolutionary evidence in a little try to find the optimal solution at the work because some of these words so look solely the influence of ideal that means that there are they were pretty much plaintext so you could use the big sort of the plaintext at the level of the known with that of sort of decipher which last basically take the width of the mix it with anything so hopefully this Council you that there was this kind of a staff and use it
for something that is war I mean I do have 2 more examples which I think was you have some time to to analyze which is there such a tool which is basically to wrongful faster so it's low substitute on the this
land such and the idea was uh place about that that's what happens when you do present-day since late at nite and the anyways where you can see that they not able to be sigh contributing to other filled with me it's I mean some of them get their 255 country will just which is less than the full allowance was so that gets 128 which sees the lessons to be and but
instead he would be accessible and you will see that the set produced the mixing weights food and power of 2 beats have 512 bits of the input that supposing that have not miss about caring the
so it and I know that is something that is going hopefully will here and and that's what it is the I guess I forgot look to the finding involves that OK so I'm sorry this is the problem of entire a lifetime of as you probably know so OK so now we have to meet folks and so sentences should now yeah so as you can see that most of the input only get 480 bits of comparison which is less than the 512 bits that that that the state contains and in some cases we have almost 3 100 bits of continuous I mean of course we cannot practice decipher with this information but we have an adult that it has flowers and that he we use 1 of concept
analysis techniques we may be able to break the in of SES plenty we will use that find that I think would be this article to working toward will put tweets and therefore it's kind of people can easily and yeah as it as it takes and then read more about the now you can see that the day it would be a set the wanting to article would be it's so because of this was that we're getting kind 512 on there because of that it means that every single bit default put gets at least at the anybody was from every single bit of the input and therefore that means that it has had with the fusion and its haplotype at his using diffusion based approach so well the
that's basically that have the most so now we are
going to use the last mile comparison of both approaches that will have on 1 side and the bike approach so well we would try to create a specific formalities by finding out the simplification of the algebraic representation using the sales for basic so so we might mapping toward energy that was the question of assuming it's quite hot but please raise your hands if you really enjoy it they I tobacco Cecil Montreal unduly high school or on university a year I think that no nobody elicit the concert you can understand why nobody does this kind of algebraic like approaches group and was simplification of this if you want to do it with a computer that be painfully is usually and and people and people and so is that we could use of analyses we have something that is simply the to wrestle we find me and I think that everybody hear and understand the concept of OK we have some inputs we have some all quotes and we are going to see hope this input Suffolk quotes each Cecil successfully in we have 3 broken siphon and uh well we'll get out hope their contributions have made will get if it somehow and if it's an we use disabled beat is affecting him some way this all could be and because of that it's really fast because we only need to run decipher and we will only need to do them alterations where n is the number of reads that they put of decipher house so the Hessian promise of course it's out fully less precise than I'm here and at the Socialist besides samples Hassan out cryptanalysis he fail I have found for example so such to without the selected analysis approach I could have formed a much bigger flowers and have fun we it that this approach and the it will you find reluctantly and create a broken sigh semi and that is that people like to find the next flower on M 4 because it will not the best of us a lot more files melodies that means that it will find a lot of sizes that you would think that's acute when they are not so this should be used it mostly for open this size and but and this that some people that is the universe and unity of my water in a little try to understand what are the flows of the safest thing analyzing but if you work a circuit analysis and their activities before them and company you cannot say my side for is totally SecureIIS conclude analyses the was it most likely will not be secured by something else so well that makes the presentation on there is some of the people the find here my moment and that in which I'm not watching this and the people that is making become possible that before and the the set of all the 4 golds please come on and there were there has been a lot of people that have supported me was there was and when my company actually allows me to take and for 5 since I don't get paid for the sets but they can do research because know have to work with the set but the most important here thanks to you for you that is him so I think we have time for like the 2 for like 1 of the 2 questions uh I guess if anybody wants to ask something because I consider placing hands or anything this even tho knowledge of the according to uh figured out sensing borrowed from some you convert the common country because people on and we do know that if you them then there is are the contributory that contains the earliest uh sometimes that so 2 beats and doesn't affect the the if you ever do 1 so do zeros he said the same uh the aspect that you you know that the holds with these and there was a kind of making it so that for example if I do any sort of ideas that specifically and then accelerated through these said at the start of the detected by content with the romances you would need to use an idea like approach if you want to detect that because it's really hard to follow up day and even beats out of the working to their to Delhi right so what they're what this will do is that it is case you will find beats that you think that contribute to a pair the Seyfert when they don't so that's why I said that you should use this order to find flowers siphon multinary because that's IFIs acute not so if I understand myself OK and the other was used I want to believe that this is because I'm really will display mean otherwise you have about that we looked at Spanish than the finite and not because they do the above this kind of thing a word that I said and their answers that hold uniform plane out there that you called
if you want to find that out method in town that you and I saw somebody that was taking pictures so please knowledge that I tend to think that the 2 you know that this OK so thanks a lot for your time and well I hope you do it the rest of the conference