Okay, a very good morning to you. It is Wednesday the 15th of December and of course we start now to kick off the central bank announcements The major ones for this week with the Fed the FMC later today Then we get the Bank of England the ECB tomorrow on Thursday And so I'm gonna jump straight in and start talking about the Fed rather than looking too much at the charts this morning things are Relatively flat. We did have in terms of the close on Wall Street a slightly negative finish Nasdaq once again slightly underperforming down around 1.1% the S&P down about three quarters of 1% In terms of where we're trading at the moment very much sideways price action As you would imagine a lot of people sitting on their hands now just awaiting the FMC announcement later In terms of the currency markets, we have got Cables a touch firmer and we've just had the UK inflation figure come out And it was quite a bit stronger than expected 5.1% against expected 4.7 Upward contributions to the change on the 12 month inflation rate between October November 2021 were quite broad based So as we've been seeing I was wearing the lights of the US kind of moving away from those more pandemic kind of Indio Syncratic issues related to more supply constraints and so on so becoming more broad based the largest coming from transport particularly motor fuels Clothing and footwear was the rationale there so cable outperforming euro dollar a little bit a bit of sterling strength this morning But look let's talk straight on the Fed because that is really the main feature of of today And this is a timeline from the analysts at Goldman Sachs And of course we're looking at turbo tapering to be announced later today. It's been very well telegraphed So the fact of that happening them increasing their tapering amount from 15 to 30 billion It's probably not going to come as a huge surprise I'd say the consensus is very much leaning in that direction and it comes amid of course the transitory word being dropped by Jerome Powell and a recent Senate speech and also generally the more hawkish turn We've heard from him and his fellow colleagues on the FMC And so yeah, this is the timeline We're looking at a tapering pace to be picked up and if they now sit now It's really to execute that plan from January and that means then by January through to then March They will look to conclude and wrap up then the process of tapering that then leaves a period of let's say roughly Two to three quarters of which then according to Goldman's they're looking and anticipating that rate rises from the Fed in May July and November and we'll have a look at a little bit of a difference then of what different banks are looking out for that But this is what's ultimately going to be quite key because not only do we get the Statement the tapering obviously announcement coming out from the Fed because it's a December meeting This is one of the four of a year on a calendar quarter Excuse me That will also get the economic projections and of the of note and the one that people will be most focused on of Course is the dot plots This is what I'm referring to here It's just the composition of the voting of the members of the FMC and Generally what we're looking at here not to go into too much detail right now is this is mapping then What goldman's are looking at as the current composition of dots on the left on each box So each box would signify where interest rates would be at the end of each subsequent year. So Then looking at so I'm just getting my bearings here So the end of next year would be here 2022 So this would be one of the closest ones watched to see how many rate hikes anticipating money end of next year 23 24 and then the long run and as you can see here the general idea is that in the near term So particularly 22 23, there's a slightly more distinct move higher in the average Median dot plot and that then is indicative of interest rates rising and goldman's like Morgan Stanley They've come out They expect the Fed to double the pace of tapering as we've discussed and they believe the dots will show two hikes in 2022 three in 2023 and four in 2024 for a total of nine and so slightly more aggressive in Fitting then with the general hawkish turn we've had from Fed commentary Now a couple of things to be aware of with the dots them themselves The one thing is is that any more hawkish kind of trajectory of rates for the future is likely going to be somewhat Offset by downside risks linked to Omicron So you'd expect a fairly tactful approach from how to come out perhaps in the press conference and if the Projections are quite aggressive to then talk it down saying look this is quite a fluid situation with Omicron We will adapt and change as we see fit and guide the market appropriately That type of classic central bank language The other thing as well is that President Joe Biden still has three Nominations to make for the Fed board and two regional Fed banks from the process of searching for new leaders So when you think about that then particularly the fact that there's three nominations for the Fed board White House officials have talked about this happening relatively soon Where it actually means then the composition of the Fed for next year might look a little bit different or at least unknown To what we actually know at this point in time And so it's hard to really take too much away from these dots because a they're hardly ever accurate Be that's because based on the reason it's very hard to predict the future And that future has become ever more uncertain under the Omicron pandemic environment and then three there's a number of people yet to be determined and so We don't have full visibility or clarity yet of their policy stance So although definitely intraday tonight you'll probably see quite a large reaction to tonight's announcement The overall takeaway might be not crystal clear until actually another month or two down the line And obviously there will be better equipped with where inflation is at this point in time Has it now peaked and so forth? So yeah, this is what we're generally looking at There's also here the goldman's have mocked up the December FMC statement This is really useful They're nearly always on point and the reason why is because there's very rarely too much text change here that happens So it's fairly easy to predict But if you want to check this out just jump on my Twitter I shared all of those graphics I've just flashed up on my screen if you want to prepare for the FMC But essentially there's some slight tweaks at the top of the paragraph and essentially this is about Previously the statement reflected Factors that are expected to be transitory and we've course now that that's going to be dropped So that's why that's been a kind of Exed out in that sense and then the others are fairly limited changes But the notable one will be further down here in around the fourth paragraph when they talk about accelerating of tapering It's from 15 to 30 billion and of course that split 20 billion for Treasury securities and up to 10 for MBS securities All right Otherwise before I move on don't forget. I'll drop the link as well on the bottom of the video If you go to Amplify me comm slash market hyphen maker pop in your email You'll get the daily email from me Deconstructing typically macro events on a day-to-day basis So if you're a student and you are thinking about a career in finance And you really want to up your game and your commercial awareness This is what I'm attempting to do with my daily emails. I also put out kind of job Adverts that I get from my contacts in the industry from investment banking to quant roles and everything in between So definitely worth checking out and we put together a weekend one where we comprised then live M&A deals SPAC deals Fundraising as well as global market stuff and crypto and DeFi as well So do check that out and feel free to subscribe otherwise the other big news of course came last night, which was a slightly perplexed Boris Johnson because he remains very much so under pressure and he suffered his biggest Rebellion since becoming Prime Minister last night almost a hundred Tory MPs voted basically against his proposal And that meant then that the ruling Conservative Party had to lean on the opposition Labour Party To support part of the key strategy for containment of this latest Omicron outbreak The Tories the rebels opposing the plan to main date mandate the use of so-called COVID passes at nightclubs and other venues in England As they tried to stem the tide of what's anticipated to be much further rising in if COVID case is led by Omicron This particularly sensitive timing because tomorrow we get the parliamentary seat of North Shropshire Which in normal time should be a fairly safe seat for the Tories They're defending a majority of almost 23,000, but they're in danger according to reports So it's apparently very tightly run against who were third place in 2019 Which is the Liberal Democrats who are going to run that Tory candidate close and again somewhat symbolic then of How the the needles kind of shifted a little bit on the popularity of the the Conservative Party at this point in time under Many different issues they've been confronting The government strategy for tackling the UK Surgeon Omicron infections is already facing setbacks as well Is what some reports are suggesting as you can see here commented in Bloomberg Medics warning of bottlenecks Starving shortages, you've also had I don't know if you've done it But I certainly did trying to book online your booster shot was Took took me about an hour because the site kept crashing You'd get through pick and date and there was no actual time slots and so on So there's a lot of pressure at the moment actually because the rollout program is facing and so you would anticipate logistical issues The Times newspaper has also reported citing the NHS leaders as saying the year-end deadline is Unlikely to be met at this point in time So that's the latest that you've got on the the situation of COVID in the UK As I said though the pound this morning is actually moving a little bit higher So it's not really reacting to politics It's reacting short-term to some of the inflation metrics that we've had as I mentioned the year-in-year CPI for the UK came in hot at five point one percent above the expected four point seven and if anything it then it just makes the Decision for the Bank of England all the more awkward tomorrow, which is they don't want to get behind the curve with tackling inflation But at the same time Omicron is going to get worse before it gets better And that's gonna Omicron lead to probably more onerous restrictions Which is going to impede economic activity going forward And so the pounds just running up to a near-term area of technical resistance from some of the price action of recent sessions going back to Last week and the beginning of the week on Monday and so a little bit of strength and out performance is sterling for now But we'll talk more about the banking Bank of England, of course tomorrow The other thing then is talking about COVID a little bit more on a global level Initial lab findings indicate that China's Sinovac shot Which is actually just given the population terms one of the world's most used in the world that saw as vaccines Concerned the latest finding suggests that the vaccine itself doesn't provide sufficient antibodies to neutralize the Omicron various virus variant some 2.3 billion doses of the vaccine have been administered so far mainly in China and the developing Wilds so yeah somewhat concerning on the fact that given those locations the size of populations obviously the Pandemic in itself is a global issue. And so given the differences in these different vaccines This is much more of a long-term effect, but one that's quite important All three us authorised covid vaccines Moderna J&J and Pfizer appear to be significantly less Protective against the Omicron variant According to laboratory testing but a booster dose likely restores most of the protection that came out of the Massachusetts General Hospital Harvard and MIT study as well over overnight yet to be peer reviewed, but Not too dissimilar from what our initial assumptions have been anyway at this point from a restrictions point of view Italy Scotland Netherlands are tightening restrictions South Korea is strengthening a social distance in measures at this point in time so everyone's trying to get ahead of the curve and Contain at least limit the impact of what Omicron is likely to have going forward Few other final points just to cover off. We've done some Chinese data overnight We had the Chinese industrial production number for November year and year came in touch firm and expected 3.8 against 3.6% expected retail sales though were touch week 3.9 against 4.6% Markets really for the European Open not reacting or too bothered by those Chinese metrics We've had the UK data. So then we move over to what else is in store for this afternoon Ahead of the FMC. We do get the latest US retail sales report analysts at ING Note that it's set to post another decent outcome Thanks to rising incomes and wealth providing a strong underpinning for spending Industrial production should also grow strongly since manufacturing surveys have all been pointing to robust activity And then yeah, we go to Before the Fed the oil infantry numbers Just a recap. You did have the API's last night and we had the headline figure was a drawdown 815,000 slightly Smaller drawdown than anticipated at 1.7 cushing those size will build 2.257 gasoline 426 distillates a drawer of a million No real definable impact though short-term in WTI front-month futures And then the Fed at 7 obviously a two-part event as usual And then we'll get the press conference of drone powell What my plan of action is is I'm not going to cover the Fed live But what I will do is I'll come on and I will do a video debrief at the close of Wall Street trade So you're fully up and running then for what happened and also then for Thursday's trading session All right with that have a good day and yeah, catch you later on this evening. Take care


In this video I'm going to show you one of the best selling products for this Q4. This product fits in the building toys niche which we can see year on year during the Q4 months spikes massively in popularity. As you can see it's a kit that you can put together in many different ways to build many different structures. It's a great toy that the whole family can have fun with together making it the ideal gift for Christmas Day. We can see here it has 1.3 million views but views doesn't always equal purchases. We need to see what people are saying about this in the comments section. So we can see here April says buy two. She's so glad that she did and her kids love it. Ross says he has this for his grandchildren. Ebony says she's just bought this for her kids. Priscilla says her grandchild got it last Christmas. Mark says he's just bought these for his kids. So as we can see people are 100% buying this product. If we check out the newest comments we can see one day, one day, one day, two days, one day, one day, one day. This is a great indicator. This is still current, still active and still making money. We can see this company is selling 66 pieces for $40 and we can see we can get the exact same product 66 pieces for about $10.


This is stock number 7J142A, a 2017 Jeep Cherokee Latitude. We are here at Summit Automotive checking out this super clean ride. This vehicle has the 2.4 liter multi-air motor, which pumps out 184 horsepower. From this HD video, you'll be able to tell that this Jeep is like new all the way around. We shoot all of our videos in 1080p, so if you have HD capabilities on your computer tablet or smartphone device, turn them on now, because it's like you're right here looking at the vehicle with me. Driver's side rim is in excellent shape, no scuffs or scrapes. It has Firestone Destination 225, 60R17 tires, and these tires look like they have about 80 to 90% of the tread left on them. Bright white is the color. This Jeep has LED running lights, HID by Xenon headlights, and factory fog lights. In 2017, they started putting HID headlights standard on the Latitude package. Front bumper is very clean, no scuffs or scrapes. Passenger side rim is very clean as well, no scuffs or scrapes on that. As you go down this side of the vehicle, you can see just how clean the body is, how reflective and glass like that paint is. We take these HD videos so if you are far away, or even if you're close by and you just cannot make the trip down, you can still see the vehicle, hear the vehicle, and have confidence in what you're looking at before you even get here. I didn't see one single dent or ding down this side of the vehicle. All the lower rockers look really good there. Back rim is in excellent shape as well, no scuffs or scrapes. See on the Cherokee, they put in four-wheel disc brakes on here. Good stopping power. Back tires have just as much tread as the front tires, maybe even just a hair bit more. Rear bumper and quarter is in excellent condition. No scuffs or scrapes on that rear bumper, and you can see that this one does in fact have the backup sensors. It also has blind spot monitoring on it. You can see it does have a backup camera, and those are LED taillights. So they've been proven to shine faster, brighter, and farther than normal halogen. Back storage area, very, very clean. It does have the subwoofer back here, and it does have the tire inflator kit. They stopped putting spare tires in these vehicles because they were weighing the vehicles down and nobody was ever using them. So they just put an inflator kit in there. On this side of the vehicle, just as clean as the passenger side, not one dent or ding. Once again, this back rim here, all the rims are in excellent shape. But down this side, no dents or dings. Very, very clean car all the way around. It does have the blind spot monitoring right there. You've got built-in directional signals, and then these mirrors are heated as well. Inside the latitude package, you get the black cloth interior. There are no rips, there are no tears on the seats. Very, very clean. Does have lumbar on the driver's side, factory floor mats throughout. Power windows, power locks, and power mirrors. You have auto headlamps. And you can see that this vehicle does have 6,350 miles, and it also comes with a full tank of gas. Look at that, right there, full tank gas. Leather wrap steering wheel, we have Bluetooth audio controls. No scuffs or scrapes on that wheel. Has cruise controls on this side. Has the 5.0 touchscreen radio, AM FM capabilities. And then this is also where your backup camera shows up. Climate controls down here, and then you have an SD, USB, and AUX jack right there as well as a 12 volt power point. Leather seat, very clean as well. This one does have the in-seat storage, which a lot of people like. You can put valuables in there so nobody sees them. If you're just running into a store or something real quick. Passenger carpeting and floor mats, very clean. Does have side carrying airbags, and the headliner is very nice and clean as well. Take a quick look at the back seats, and then we will check out under the hood. Back seats are just as clean as the front seats. No rips or tears back here. Does have latch child safety system for your car seats. Very very clean. This vehicle has never been smoked in. Back storage area is very clean as well. Has this little flipper here, so that nothing falls in between. These seats are adjustable, and we got leg or knee curtain airbags here as well. This vehicle comes standard with 10 airbags, very safe vehicle. And finally we have a 115 volt, 150 watt plug-in back here. Very very clean. No rips or tears in the carpeting. This vehicle is basically like new. It's always been serviced at our shop, and locally driven. Has a 2.4 liter multi-air motor. Engine bay is very clean, runs very smooth. This Jeep has been fully safe to be inspected by our service shop. Has a fresh oil and filter change. All the fluids have been checked and topped off. And this Jeep is 100% ready to go. And to see more pictures of this one, or one of our other 400 new and used cars, trucks, SUVs, minivans, Wranglers, you name it, we got it. One of the best Jeep selections in the state. Check us out all at www.SummitAuto.com Full pictures and descriptions of every vehicle. I know a lot of videos of every single used vehicle that we have. All at SummitAuto.com. Thanks for checking out my video. If you want to make this Jeep yours, give us a call right now,<PHONE_NUMBER>. Ask for one of our sales associates to make this Jeep yours today. Once again, that number is<PHONE_NUMBER>. Thanks for checking out my video. If you want to see more, go to our YouTube channel, which is youtube.com slash SummitAuto. Remember to like, subscribe, and share. In fact, in a second you'll see a subscribe button on your left. A link to more used car videos on your right. If you haven't been to our website, on the bottom, a link to this vehicle on our website to check out more photos. Go check us out. See what we're all about. We look forward to helping you with this super clean 2017 Jeep Cherokee Latitude. Thanks again.


In our previous video we introduced the idea of symmetric key cryptography which is a method of encrypting and decrypting plain text messages. You can encrypt it to ciphertext and then you'll decrypt the ciphertext back to plain text. Symmetric key cryptography is about encrypting information so that Alice can share it with Bob and with the assumption that Alice and Bob have the same key and that any eavesdropper aka eve would not be able to decrypt the message because she doesn't have the key. Now one of the earliest examples in history of the use of symmetric key cryptography, at least in a more modern sense of how cryptography is viewed, is what's commonly referred to as the Caesar cipher, named after Julius Cever himself back in the days of ancient Rome. So the idea of the Caesar cipher is you would write down a phrase in Latin, so you might say something like Vinny Vicky Vitti, like something like I came I saw I conquered, something like that. I might be butchering the Latin right here. So you take this message, so this is just the plain text, and then you're going to shift the letters in the alphabet by like say one. So you might shift our two or whatever right, so you might replace okay we're going to go up in the alphabet so V will become a U I will be then come what becomes before I H what becomes for N M what becomes before I the H again right and then you get U H B H you get the idea here U H C H so I just what I did is I just took each letter each letter and you shifted it. You took your original letter you just shifted it to the left by one so if you think of it like as a number the idea is we just shifted everything to X minus one we went to its predecessor. But what happens if you're beginning the alphabet if you're at if you're at the letter A you would then shift back to the end of the alphabet to be Z and so essentially you just shifted everything to left working mod 26 the alphabet are being the that's 26 being the number of letters in our alphabet. Now I should mention that in the Roman the original Roman alphabet when they were speaking Latin they didn't have all the same letters that we do in English but that's beside the point we'd be working we'd be shifting things according to basically addition or subtraction mod the number of letters we have in our alphabet it's a very basic idea but this truly befuddled the goals I mean honestly Latin is hard enough to speak for the native Romans themselves I took Latin for two years it was a brutal language it is and so the barbarians were definitely perplexed when they got these messages they intercepted them they had no idea what Caesar's generals were talking about because even if they knew Latin enough to understand it this was just a bunch of gibberish even in the Latin language and so this this confused them and it was a strategic advantage for for the Romans in their conquest of Europe at the time and North Africa as well so let's let's look at another example of this thing here so let's suppose that Alice wants to use the Caesar cipher with a shift of three which by the way shifting three to the right was actually the method that Caesar himself used with this with the now called Caesar cipher and imagine Alice wants to send the message we write at noon to Bob I always love these lessons on cryptography because the message was encrypt they always have this like dark sinister tone to it we write at noon what would that mean we don't actually know the context of it Alice and Bob are trying to say here but it definitely does sound insidious right we write at noon but this is the message that she wants Bob to receive but she doesn't want Eve to receive so what she's gonna do is she's going to encrypt it now she's gonna encrypt it using this method of the Caesar cipher and so I actually have some magma code set up to compute this exact same thing and I'll show you to you in just a second so you use the command Caesar encrypt Caesar encrypt takes three parameters the first one will be the plain text message it should be something with this regular characters or in terms of the computer language this should be a string it'll be it'll be preceded and followed by quotation marks following the quotation marks you have a comma to represent the next parameter for the case of the Caesar cipher this parameter is gonna be a one we'll talk about in the next video what happens if you change this parameter but for Caesar encryption put in the number one right there and then the last number will be the shift that you want to do and this will always consider this a shift to the right so we'll shift by three which admittedly as we're working on 26 if you want to a shift to the left by one you can put in a negative one and it should compile just fine and so if you run the Caesar encrypt code on magma it'll send you the following message Zulu go back to do what cook it's kind of almost sounds like something like the the Swedish chef would say something and so the Caesar encrypt it shakes this plain text message and gives you a bunch of gibberish right which if anyone sees this they're gonna have no idea what this is saying all right so how did it work well the basic idea behind the Caesar encrypt algorithm when you go towards the magma code like I said it takes in three parameters the plain text a will talk about a little bit later and then B is our shift so the very first thing it does is it's going to take the plain text and it's going to turn it into a string of numbers using the digitized command we had talked about in the previous video and so then initializes our cipher text C just by taking an empty array okay and so then what happens is that it's going to run a for loop a for loop meaning that's gonna it's gonna perform the same operation over and over as it goes from one to the length of P so in magma pound P this is the length of the array so for each letter in the plain text is going to perform the following operation so you're gonna take a times PI plus B PI right here so since P is an array P bracket some index there gives gonna grab the ith entry of that array so you're gonna times it by a which of course is one so it's doing nothing in the situation you're gonna times it by a and they're gonna add the number B to it so since PI is a number we're gonna add B to it and then we're gonna reduce that number mod 26 we're then going to add that number to C since C starts off as an empty array cat right here means we're gonna concatenate this array with a single entry to it so we're just gonna add it to the end of our array and build it up so we're gonna get an array of numbers and then at the end we alphabetize and we turn that array of numbers back into letters and so in the end product as we get this Swedish chef comment right here and it's gonna be just but just random random information which then the shift is hidden inside of that thing and so there we go so that's that's how we encrypted this thing well I'll show you how to do this in magma in just one second so perhaps to the contrary though Alice is concerned that if she sends the message we write at noon although we can see spacing we can see capitalization our digitized command ignore spacing and it ignores capitalization so and lowercase letters as well it treats everything as an uppercase letter so when Bob decrypts this and we'll talk exactly how to do that in just a moment when Bob decrypts this then it's gonna have all the letters squished together there's not gonna be any lowercase letters whatsoever so she's concerned that might be hard for Bob to know when one word starts and the other word ends so she might instead add some little fillers into the message so she might write something like W.E.X.R.I.D.E.X.A.T.X.N.O.O.N. why are we doing that well the idea is the letter X is a very uncommon letter in the English language therefore if we insert letter X's that's essentially taking the place of like a space so Bob then when when he looks at the plaintext again he can see oh we ride at noon oh I know what to do and then he goes does whatever the thing they supposed to do this of course will change the ciphertext so you get Zalga had walk or rock or whatever it is right and so that's because all these extra letters are in there X's which again Bob will be able to decrypt them with the appropriate command we'll talk about that in just a second so let's go back over here to magma so if we wanted to implement this operation of magma we need to include the command Caesar encrypt which the code you can either copy from the screen you saw there or more likely click on the link in the description to take you to github for which you can copy all of this magma code and magma can be run on the following website where you can see right here which is also linked in the description of this video now to run cipher text the cipher encrypt you do need to have the digitized command and the alphabetized command copy and pasted prior to the pasting of a Caesar encrypt which you can see these commands already right here in my compiler Caesar decrypt will talk about that just in a second and so I want to show you what happens that we run these commands so what's going on here is that we have our command Caesar encrypt we have our message we have our parameters one and three right here in magma if you have a double forward slash in front of something that I'll actually comment it out so magma will ignore that command so if I run it right now there's no output if I remove the comment there and I run Caesar encrypt you now get this gobbledygook if I do the second one right here you run it again that's where these things come from if you change your parameters let's we want to shift by five right then you'll get a different message and so the shift is the key if you know what the shift is then you know what the original message is we'll talk more about that just just this moment right here actually so now let's suppose that Bob receives a message from Alice it's let's say he receives the message department of justice homeland encryption unified division no I don't think that's what that meant this is this is clearly a cipher text right this looks like gibberish so what Bob needs to do is he needs to decrypt it now he knows that Bob and himself are using the cipher shift key of B3 he knows that's the key and so what he's gonna do is he's gonna run the cipher decrypt algorithm which this is the inverse operation to the encryption mapping we talked about earlier it takes on three parameters the first parameter will be the cipher text the second parameter at the moment it's gonna be one we'll talk about what that does a little bit later and then the third parameter is gonna be his analysis secret key which is in this case a shift to the right by three when he runs the Caesar decrypt procedure he's gonna get the message algebra all right and that means something to to Alice and Bob which we know if anyone sends the message algebra that must be diabolical here's the actual code for Caesar decrypt you can copy it from the screen right here or more likely copy it either from the attached lecture notes to this video or from the github link is probably the best way to get a hold of this so what seizure decrypts gonna do is it's gonna first take the cipher text and it's gonna digitize it we need them to be numbers so that we can do algebraic operations on it then we're gonna initialize the plain text just as an empty array and what we have to do is because of this number a we might need the inverse of it again I'll talk to that a little bit later but as the number a we're just using as a one right now it would compute the multiplicative inverse of a which in this case will just be one and so then it's going to be basically solving the linear modular equation from before so the the previous equation took a x well you take x and you translate it to ax plus b well if you want to solve this equation you're gonna have to take the inverse of a times it by c and then subtract from it the inverse of b like so so that that's all we're doing so we're just solving the we're just solving the linear equation mod 26 and so that's then you do a for loop and you do this for each letter and see one by one you just reverse you on you you unshifted back to where it was and then you're gonna alphabetize it and so that's what we're trying to explain right here the encryption process as you send x to x plus b the decryption process then says you'll take y and you'll send it y minus b mod n that's the basic idea behind the Caesar the Caesar cipher in that regard so if we switch over to magma again let's take a look at that we will comment out Caesar encrypt encrypt we don't care about that one I already have the Caesar decrypt pasted on the screen right here and so what happens if we run that one we'll submit it and so we get back you put in this DOJ HEUD we get back algebra if I just type in some random message right something like this and you run it you get back also something random because the message that I just typed in right now this was not a legitimate message to begin with so when you decrypt it you get back a bunch of gibberish all right now of course if I put these processes together I might say something like the following let's Caesar say Caesar encrypt a message what we want to say we might say something like magma let that be our message right now it seems insidious right so let's say we do the shift of seven if we encrypt it I'm gonna actually save this as e and then so that you can see it on the screen I'm gonna type in e right there and then I'm gonna run the decryption process using the message e I don't need I don't want quotations in that case because if I do quotations around e it'll think my message is e and not the function or not the variable e that has it saved so now we want to run seven as our as our key right there and so you run it then the the ciphertext is gonna be th and th and you know that that's gibberish but then the the plain text is magma right there now be aware that if use a different key to encrypt versus decrypt you're not gonna get something back like so the encrypted message is RFL RF right that's the ciphertext but when you decrypt it using seven instead of five you end up getting back KYE KY right that that's that's not a real message right there and so it's imperative that those who are working to decrypt it have to use the same key as who encrypted it Alice and Bob need to have the same key so the symmetric key cartography met methods we talked about the Caesar cipher being one of them it has the benefit of being easier to use compared to other crypto systems we'll talk about for example public key cartography in the next lecture which is much more sophisticated but symmetric key cartography has the weakness that both keys are both both parties communicate must have the same key and that key has to remain secure if one of the parties doesn't have the key then they can't either encrypt or decrypt you can't communicate effectively like we saw just a moment ago and if any eavesdropper like Eve has the key then she also can decrypt the messages and she also can encrypt messages and pretend to be Alice so there's some authentication identity problems with that as well and so a symmetric key cartography the more parties involved in the communication the harder it will be to keep the secret key safe if an encryption process is compromised for example if an enemy captures an officer and learns the details of the encryption process through interrogation or maybe even torture yikes all past encrypted message are now vulnerable to be read all future messages can be protected by adjusting the encryption process this can be this is best done by switching the encryption key if Alec or if Eve knows that Alice and Bob are encrypting messages via the Caesar cipher and they shift everything by three then she can read all the messages and so therefore if once Alice and Bob discover this then they're like oh we're gonna we're gonna switch our key from three to 17 all right that's how we're gonna do this to try to protect future messages well and switch switching encryption method hastily is impractical since the encryption method will likely be part of the communication infrastructure right we have our infrastructure has built into it maybe the Caesar cipher so we can't be like oh she figured out we're doing the Caesar cipher we're now gonna go do the hill cipher next that would be too fast too difficult to do it and so typically a new key can easily be constructed and distributed right so we then have to we'll just be like oh we'll keep on using the Caesar cipher but we use a new key and that then has to be securely shared that's an issue in of itself which I won't talk too much about right now so for this reason the security of any reliable crypto system must not rest on the secret of the encryption method but instead must be on the key of the encryption of the encrypted system itself what I'm trying to say is if Alice and Bob expect to have safe communications the secret should not be how the Caesar cipher works if your encryption method is itself the secret eventually that'll leak out and you will not have enough time to develop a new system before your information is compromised the security needs to be on the key not on the method itself so we should assume that Eve knows these two are communicating using the Caesar cipher but on the other hand if they know it's a Caesar cipher how many keys are there with the Caesar shift the method has only 26 encryption keys which correspond to the 26 letters of the alphabet and you could try to beef that up by like saying oh okay we'll use lowercase letters so that I've doubled that we can use special characters like commas and periods in percentages or whatever symbols you want right so you could do sort of like an ASCII code which I think goes up to what 255 characters or whatever but the the the strength of the Caesar cipher is dependent upon how big the alphabet is how many letters are in the alphabet because that gives you the possible shifts well with only 26 letters it would take a computer no effort to search every possibility and see which decryptions actually give you plain English in which ones don't even a person doing it by hand it would 26 attempts would not take that long I mean it would be a moderate feat but it would be doable right this is what's commonly referred to as a brute force attack brute force attack meaning that you look at every possible you look at every possibility and see which one works generally speaking brute force attack is not very effective if you have a good crypto system because there's just too many possibilities if you're working mod 26 that's just too small it would be easy to brute force that even if you're working mod 255 or I guess 256 or whatever if you if you had something like that that's still would be too easy for a computer to do so in the end although the Caesar cipher worked very well back in ancient Rome in the modern digital age with with technology computers we need a much we need a much larger number of possibilities if we want our encryption to be secured from just brute force attack