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Layer 1 encryption and decryption


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Title Layer 1 encryption and decryption
Subtitle Layer One challenge
Alternative Title Titkosítás és visszafejtés a fizikai réteg szintjén
Title of Series Hacktivity 2015
Part Number 14
Number of Parts 29
Author Miklós, Bíró László
License CC Attribution 3.0 Germany:
You are free to use, adapt and copy, distribute and transmit the work or content in adapted or unchanged form for any legal purpose as long as the work is attributed to the author in the manner specified by the author or licensor.
DOI 10.5446/18843
Publisher Hacktivity
Release Date 2015
Language English

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Subject Area Computer Science
Abstract Ha a fizikai rétegrol beszélünk, mindenki drótokra és optikai kapcsolatokra gondol, miközben a modern kommunikáció jelentos része vezeték nélkül zajlik. A rendelkezésre álló frekvenciaspektrum jobb kihasználáshoz az eszközök frekvenciaugratásos technikákat használnak, azaz mind a leadó-, mind a vevo-berendezés másodpercenként több ezerszer vált frekvenciát. A megfelelo kommunikáció biztosításához a leadót és a vevot szinkronban kell tartani. A kereskedelmi használatban ezt frekvenciaugratásos eloírások biztosítják. Ha a kommunikációt tovább akarjuk titkosítani, csak annyit kell tennünk, hogy nem szabványos eloírást használunk, így harmadik fél nem tudja veszteség nélkül összegyojteni az átvitt adatokat, ez a veszteség pedig megakadályozza a tartalom titkosítását megfejtését. A digitális jelfeldolgozás új eszközt biztosít minden átvitt karakterfüzér azonosítására és összegyujtésére.
Keywords Frequenzspektrum

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you know word you know you have a choice you OK good afternoon to all of you gentlemen and ladies have most of you are still widely if you aren't of try to make them more or when we
talk about digital communication everybody knows the 7 layer OSI model of the group's work and when we talk about detection or checking we usually talk about later student 3 where we're looking for the variance so we this is that attack points and these are the basic without the protections maybe we extend this layer for but not further and later 1 that we almost a physical layer we don't have to do anything with that to me is that every kid wired up somehow and we do trust that it works as it should this however depends on the components to be use in the network traditionally uh we have been using wired networks copper-based that reason about the optical fiber networks speed not really dangerous and not really interesting because if you really wants to attack a network like this sort of compromise that would like this and they will need to access to all the stuff for the for the moment forget about the situations where Dutroux administrators and defines a set of water and the variance of the traffic of a natural branch instead this thing called the classical like having that that on a wired net worth therefore we connect a friend device measurement unit to this natural this is feasible and this will cause the physical parameters of ever to be measurably change their reflections are generated by the extraneous device and the reflections also allows us to kind to wear that reports compromise awareness this of extraneous device was connected the syllabus to an optical that if I catch a a fiber-optic connectors 2 fractured off it also cause reflections which are which can be measured and the runtime of the signal of at the time and to the reflection arrives back at the origin enables us to determine where exactly physically or natural was changed if we consider wireless networks this is a bit more interesting of the if we have a Wi-Fi network we can monitor it for days or weeks or months listen to the traffic it will leave no trace behind being attacked the host and the owner of the detectors of the tax system would perhaps only noticed that something is wrong because data that you thought to have protected are starting to be used by unauthorized parties with another of the possibility is that the owner will realize that he is the author of associative memory in the middle attack so it's a local station was replaced by another 1 and the data that the owners thought were protected are being used but you can get much of interest from a lot Wi-Fi regret we do hold let's hope that we can because by 500 years up pretty well known for the situation becomes more interesting
therefore we want to sort of eavesdrop on the cover communication which were not which was not meant to be able to be accessed by simple means by anybody and here this is not only the data content because it's about it in a condom that carries information but also what the 2 endpoints are that the communicating this is a more
interesting scenario for instance you know the civil link 16 communication also went on in Hungary which is not from man and for many years the the distress communication among Hungarian and of the makes is using this communication and is the goal was to hide this from and normal now our once something has been irradiated as a radio signal it is in the in the and with appropriate devices anybody can listen to them and can use assuming he is able to put together the data segments and not the time it takes to decode it only depends on his computing capacity that he can lower the task since communications in the is analyzed well this animal communication is protected by some to meet their their digital predictions encryption that are related to 2nd place because of
communications have been working extracted they say stuff we talk about later ones and wireless communication then we're saying that later 1 cannot be increased to this and other communication and signals that passes through the center of nothing to be done with that the country would be protected because with the should be irradiated into all directions before and even if you have a directed antenna and a point-to-point connection even when you have scatterings was you know based on the eigenspread melt principle that signals are reflected from other obstacles and radiating all sorts of directions so you cannot even determine that anybody is listening to this topic and you cannot to disable them from doing so the
international radio communications for what we used to have was the center of which was due to a specific frequency a receiver was also tune into the same frequency we started about we knew press the button justices started at the receiver receives the transmitted signal this is not really sick at vision method so we certainly do you need something that can help in digital radiocommunications to stick to logical steps they open up new opportunities and possibilities and 1 is that so-called direct digital synthesizer is transmitted as appeared this means that I tell the sender to operate at specific frequencies and the center will then the a tune into the another segment of tens of seconds and the and and the receiver is a software-defined radio the heart it can also be told what to contribute into frequency or it can be made to monitor over a broad frequency spectrum and to the show in radio communications finds within this broad peaks of the spectrum of people if i in all the sender frequency I think you to that frequency with my received if these frequencies are or change sufficiently frequent use of the of the stopper will not be able to find the next occurrence of the I continue my in the transmission of some of us so I also can also digitize my voice is signal and makes it for much of its it with the with the with other digital data and I came in this in and use a lot of a big number of frequencies simultaneously so I can change transmission and reception the frequencies very frequently this is called a frequency I can even using pseudo random sequence of low frequencies and hope that the opponent will not be able to find my this is what the frequency of the look like all of the the sender works at a specific frequency for a certain time this is speculation number 1 on we ascendance voice data of the data in digital encoding and it should be encoded this is 1 of the 1st period I give some time to both the sender and the receiver to tune into the next frequency this is the so-called black times the center during this time you use into to the new frequency to be sent on and this actually also to look to see if you can do want now the 2nd batch the 2nd package of data is sent by the sender and this is continued on with the same thing for a man and decided to working on this topic we were curious about the frequency of changes and we were told that this is a classifier data so we had a closer look at this a equipment and Texas Instruments manufactures the chips of the musical culture as it about so we visited this system and its home base and we found a very nice table about the setting of the chips is is able to do and we found that 1 of the slowest to frequency hot is well over hundred pops but 2nd and that in the next few cases it can go up to to 30 200 the frequency changes per 2nd this means that if you if I pick up a channel 1 challenge of of of this mission I want you to do anything with it just hear the beep that's also a chemical is a traditional receiver to capture these kind on the sender side we have the so called directory assistance lies that generates the frequency of using to test me on and this frequency will be determined by the pseudorandom generators the signal will be amplified all of the including modulated by the that and that and that I want to transmit and made it is transmitted of pseudorandom generator must match with leads to the random generator in the receiver the which also generates a frequency that should be the transmitter sending frequency of and then we'll this similar can be decoded on the receiver side and processed so from this point on the my I have a digital signal flow and all I have to do is use the key to decode the transmitted data course here in gain we are faced with the problem of the process itself is that once again declared to be classified so what all we could once again goal of turn to the vendor of the distance to effectively appropriate chips and we can we could extract the super sensitive
information that will not that was not much to us when we requested so if I want to decode a message like this and I need to the concatenated the various bits of information that we tested it on different frequencies so any of the entire package chain 1 and only then can I be encoded so 1st I need to hunt together all the packages can cake made them to a contiguous a signal long and then I can apply the devices for decoding will cracking signal-flow if I know the algorithm for the for the random frequency generation as well and this is relatively simple so if I have a lot of that parent topic to have to get equipment and it's easy if I do not however if you know how the to the random generator operationalize and trouble because I'll have to look add that they're not in each weighting I'll have to find the next lecture the figures of the next the carrier frequency than expected the ratio frequency hopping we have mentioned that in the few frequencies actually Texas Instruments USA 17 and they follow each other in the steps of 1 migrants for instance the equipment by showing you it's not a big chunk but if I don't know what very where where the hobby is so in the in artists higher-order be lower than mine and I'm in problem I'm sure everybody all of you have equipment on your person that uses frequency hopping with us have it on this person
obviously if you know what about what it's about and then you will know that our are skin graphical seconds to work that there 1 of the classical frequency and devices at cell that use the so so book itself out and the last number of bits are capable of directing the synthesis changed the frequency of the transmission and also for receiving and concatenation and according to the whatever the receiver should I actually required in in order to perform such an activity we have already mentioned and sort of software defined radio this is the only device which is capable of concatenating the frequency of the transmissions its most important characteristic is that while the traditional radio frequency transmitters actually it works in a way that it selects this certain frequencies of these other ones so you can see the whole range of frequencies and digitalizes them into the 12 or even 24 it's dead and from the spectrum with an FFT Fast transformation is actually select set the frequencies that might be of interest to me so I can see fights and 100 megahertz spectrum and within that spectrum with that of other children methods I select those that I'm going real transmission frequencies which is noise which has to be subdued and from the interesting frequencies which is the 1 that's going to my random number generation is the transmission assigned to me very similar to the old panoramic receivers we but this is several frequencies simultaneously little panoramic receivers actually swept through arranged through a spectrum and I could not see in real time everything simultaneously 1 with some sort of duly sort of the frequencies of simultaneously in real time I could not according to
the current system in which the frequency of the light used was the other professional therefore the Belgian would assure and the of the company is not small it's 40 kilograms and works with the 20 were better resolution I can analyze the spectrum that we find interesting 220 gigahertz we presented a few examples of their device on how such a frequency whole thing communication looks like the
easiest which images in which you know about yourself because this rather simple dual band GSM phone works at 900 megahertz 1 particular you can see a huge impulse 900 megahertz this we were the 1st to complicated when you see a smaller 1 1 agrees with the 1st that there a reason 100 megahertz 1 available as well as the see half of the size of the students through its 200 megahertz sensitivity is in fact you know if we observe this communication all of them we deliberately made the
fluent into constant and communication that we started talking about 4 months and you can see that it uses a separate frequencies all this a nice cheap towards the rise action issues related communicating with the frequency distribution is and what the energy distribution in history is practically evenly distributed on the set of frequencies in their energy environment that's the cell
wishes to transmit the utricle closer and observe the strips
angular shape pose with them we see but a told is undulating the bullets deceiver can still send sets and then this little diagram and we can see the data packages
every single horizontal line is that this package and the data packages that you just put together
a gnostic an even closer look some of our we see the same frequency of the experts the 2 sizes the parasite frequencies of the persona programs which are due to the distortion of the transmitted in the middle of the frequency distribution is quite simple but the page is near the parasites instances of the problem but the receiver can actually handle managed situation adequate and receive signals that we didn't have to deal with we to have to work with if we open up so it should be from the set of all and
we see that we even within the peak here there is a movement of some the waterfall diagram is tied to the saturated the data about pictures that actually could cost of the whole thing from precursors
of this is that coming in afterward and the users we have to distinguish among these are the ones that we have used to compile the frequency always on the designs of which contains the communication valuable to let us take an even
closer 1 single adults on the waterfall diagram uh signifies that date back to the real time we have to locate that and the number of data packages that belong together we do get some help but not too
much time 1 he say that the transmitted is not capable of a large frequency of the disease that can change the frequency they have development in the behind them you know at the end it may not be able to do and that's what we can look at 1 frequency Donetsk quite to say that we can only hold on to an extent of 5 to 8 per cent with creativity in order to ensure the survival of the transmission and to make sure that the
international transmits the signal the mean estimates of subsets of thought is that all of a the frequency hopping we have created a situation where the receiving device that we have not at we have not true and I understand that the world situation because it's actually has to select the packages in a way that the content of the those on the frequency is also on on the frequency of the order of frequency and also on on the schedule sequences the same time it has to compile compile them on the set of communication that the world which has also advantages on the 1 hand it is protected against the channel is the jammer has to be able to perform the same sort of frequency with the same time as performed by a transmitter and receiver and at the same time it's extensive protected against competition with and the other in the reduce stations and mitigate the danger that it goes to Washington that to and the composition composition of these packages is made up in a way that's the receiving was unsuccessful than the can for a reiteration this as we have seen is quite difficult to compile that it's packages would be and this is more or less lost in the background in the last year we sold the very noisy background the transmitter that is capable of all for trends so that receiver this Cabletron transmitting that we have a set of nodes that was the frequencies is is capable of performing the computation of that is another advantage is conventional receivers can also read state so what we see here is 30 foreseeable really good quality printing used by the
Defense Fund founded which cannot be interesting 1 is is also advantages for instance in military stationed in working with great there is has to functional and which 1 is search modes and 1 of is target of music that is called the readout devices as in the case of the model to 31 regression which we haven't really used it can be performed simultaneously constantly searches in the plans and the interesting thing suspicious tools in the the aircraft and the machine that this will on the region this is a good and senses that the reader has now switched tracking and structural and if this is sort of machine learning they will do nothing fix the military and she has nothing to do they have to really
embarrassed to say the least and trying to escape tracking can be recognized by the fact that a judge impose the costs of the following the longitudinal when there is no point at which the services that use the frequency of the on the interplay in the travel not notice that this is the full because it was 1 battalion false and then the next 1 and policies in a different frequency that is not distributed and because of that it was the frequency has changed and we would expect the balance of signal at the same frequency as well the main issue here is that the status of the practical use of this is being tracked In order for such a frequency hoping communication to be acquired with new software defined radio 1 has the hypothesis that is similar to to that Aldershot's receiving that resource provides which only has 1 problem namely the because you 100 thousand euros whatever lies to bring it home with you and there also the 1st and what does this machinery that the smaller ones to knowledge on utilizes up to 24 bits of received a very good digital signal which can conditions has enormous calculation capacity to they can perform their efforts procedure very efficiently personal fortunate thing not sufficient enough and to this
procedure such a frequency of transmission that actually itself that is the 1st what 1 of these cost you 50 dollars which with 12 bits resolution is a bit slower than the previous and introduction attitudes thought the receiver has a good DVB-T receiver which course your test and always also shows you how many signals you have in this pension but that's the end of the line because the installed calculation and process is inadequate for us to perform the transformation estimation of enable us to compare the sample and the resolution of all the device is inadequate %
correlations of the so in order for me to concatenated data packages that must be able to recognize what blocks on compensation transmits and this is interesting for many aspects because you want to define find the location of the transmitter the 92 2 and the direction of its measured the direction that examine that they available tell you the frequency with which a lot of interaction so I have to identify what transmitted data can also come from and that the ability to compile all the signals coming from a given transmitter I will take into consideration to characteristics of the transmitted signal 1 is the harmonic content which is constructed characteristic of the transmitter was not the worst and you can change and the other 1 is the end of the it namely how this transmission is commenced with what's you a force peace can be transmissions stabilize and transmission ceases to how long does that take to happen transients we can count and then based upon that survive adequate admission capacity available to that's
what is most from 1931 came from the same transmission operations content can be defined by the effort to receives them on a continent 2 transmitters 1 was a traditional 1 of the harmonic content what comes from the distortion of the transmission transmits essentially has this year Hungarian background but allows seek actually published a rise in this environment in news of Wonderment noise frequency spectrum but he came up with that of the findings has published a book which has a floppy supplemented with that of Gossage and what could be calculated with the idea that the fact that people seeking actually before this is 1 element of that we examined the harmonic
content the 1 that was the end of the is but I really operates in the transmitter about status according to the 1st image the transmitter switches on it reaches its nominal performance transmits the data little bits of it which is of and as the transients died down the radiation in transmission and on the 2nd images the transmitter which performed and over short this the slow status of received a ball of logic of formants transmission and and his laws we can see along distribution of the transmission of this program is very similar cases of which transmitted which the extension we said we can examine the 1st portable doesn't periods of Y of the parameters of the harmonic content have so what we initially things like the that 1 last thing I would like these all dependent and the construction of the channel as the 1st of the attributes of stocks and so we can see that the temperature starts rising so the 1st will but the 2nd 1 the 2nd 1 over the other 1 and I have 22nd this really is the sequence of
states that we saw in the case of the envelopes so this means that the transistor is working in a stable condition for that reason we analyze the 1st 10 or so years that's what we want to examine the invisible not the review of the creator consonants can be identified as this and hence should be called transmission and printing and
searching for the transmits so what do we have to do we have to inspect every single you have to figure out to itself of them to inspect them and to calculate the harmonic content that we have to we examined the actually we have to have these all these things on the the chart if that 1 of those numbers you should have the the same into lands that they both came from the same transmitter and well harmony and not much if I I have a with that that 200 to frequency hopping around the world time and other 311 might sex this is very little from this the dwell time the active transmission times 50 microsoft excel in I haven't been to all variables it's so frequency see that the 1st 20 periods stick 2079 asserts during the 17 IV able to build up role of the property table so that means determine the harmonics content and the shape of the envelope this won't fly it it is impossible to perform this calculation by the by the time the next what time the rights so I need to gain some time
somewhere of course how can you win wouldn't have team at Microsoft makes the bottom you see here's switching diagram this is a delay line on the that it appeared in practice in the beginning of the thirties of the new century it was used you what you see is the a is the delayed other Hammond or organ of the I think of the 2nd session extremely can see the delay line for the time being settings of a computer manufactured in the seventies and on 1 and I in here in use the signal at X is on the other end of and ancient to the well-being of the points that can be used to model and have to get out of the delayed signal the 3rd 1 is seen as an acoustic cue delay line will ya know what do for it to you this is a very small very stable very low distortion and extremely cheap as with because
work that problem about the atomic signal is to convert it to alter the sound and sent through a group about appropriately body shape quartz crystal of sound propagation damage to give lower than that of reducing that it also bounces control of the crystals so it too will love experiences significant or he is dealing actually in this case the 1 TV line in the limit of the article it will be a undistorted and unchanged at the other end of the excitatory without
affecting is harmonics content or and a lot of people so the at the output of the delay line I have the signal available without the harmonic content or its analog haven't changed at all so this gives me more time to process of what I said when send signal into the related to the delay line by
study of 50 ideas started uh in this in media the envelope and I have to separate the lowest related to prior to the 1 branch is sent to the delay line and that the system signal the other branch is sent to the US at university or receive group which which has its only task to calculate the shape of the envelope of the harmonics companies for its 2 bits of information received in kinds of information out even process there in immediately handed over to us as the logic to it is using the process of reasoning which was a RISC processor and of course for the task of will compile the properties stable and based on the properties table it will be called tells the SDR receiver which was similar to recreate because this paper this package is the continuation of the previous back into the community for so with this line by 1 of the world by getting the amount of time needed to process and this means that in class real time with a view of government might have 6 of the late I have available the signal that the center of thought was projected because they want to be able to find the sequence of discover minus 6 is the limit of this not disturbing if you're new to election measuring and if you want to call it the cold the complete signal then it doesn't affect us all in the case of voice communication kilometers 60 Linear doesn't count at all the of this process can of course be redefined by the board of the Book of Mormon if I attach the line like I showed you it was possible with this why should you be alright concatenating 2 ultrasonic lady lines and with the intermediate with industry on the receiver in between the 2 I find my calculations and the of the 1st this year I was not unable to this side of of the room which reduces them to what can I the 2nd stage we call these uh few remaining from estimate process and that process that with the 2nd stage and you end up with all associated with the restored complete communication so by adding a delay layer into the signal I will obtain the extra time needed to process the the entire signal more than you think this is roughly what it is all about and the idea
was again we to see the receiver equipment because by increasing the delay I can gain from any arbitrary amount of time we have our own decreasing processing quality so you can play around with these devices and the even to hold meetings with them because the processing the processing that does the Digital Signal Processing Conference is being a good quality video card or of a unit can work to a Citigroup so remote that would have multiple video clients and you can start trying restoring signals and the only thing to take into account is that this is a protected by process to patent pending
and if you want to use it for commercial purposes and let me tell you that I like I gotta be so this is where w hearing questions I'd like I'm happy to answer them again and again so the only serious histories the pseudorandom generator stuff right of this and not only is the degree of frequency hopping I'm in the in the number of hops has been defined by the chips and the the the size of a chance to get a jump all Hobbes is defined by the receiver is going to mechanical design density frequency various optimal and that the the by sort of the the evolving I'll experienced standing waves that power will be of the most effective from the internet so you can jump to and then it to major to be jumps 5 to 8 % is the largest amount of the and on the other hand the important thing is that if you do not want to do that so that it's use use a real random generator and you embedded in the package that the crystal the the next frequency set and the and you cannot use traditional methods to decode this fact extreme because you have to 1st decode the package to find think was a bottle of I can determine the gestural fingerprinting determined of this package comes from the previous 2 2 is the addition of previous package than I have 1 time and was able to hold this industry hi annotated you when they have they been evident in the form of a all of would like it for to look at this yes this and again allows us to the year when the intuition is kid this off well thank you for your attention fj
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