 Hey, we're back checking out tutorial level three in the Pico CTF challenge here This one is called color apparently you can go see it on the left hand side of the desktop here Click that open me icon and we get that challenge prompt So here we go challenge title just tutorial three challenge prompt is Robin handed me some color codes the other day They don't look like anything to me though. Can you help me find her favorite shade of red? So the hints here again probably tools on the internet that can help and that's a clear theme you'll hear from All of the capture flag competitions that you do Search engines are your friend. You've got to learn to Google. You got to learn to keep trying. That's Cali Linux offensive securities motto Try harder keep trying research things and try and learn on your own So let's see what we have click on that codes link and we get a new text file Here are a few of my favorite things So these look weird, right? These clearly aren't colors. They just look like numbers and letters So let's let's Google. Let's just see what one of these things is If we just paste it in here Do we get anything? Oh, okay. So the first couple results here are color hex Color hex Let's try it Hmm. This looks Like something whatever looks like kind of a brown ish. Maybe yeah pretty much brown. Just maybe a dark orange 7a 3b 0 0 color RGB value is 1 2 2 59 0 What does that mean? So This is a hexadecimal representation of a color or something that you see on Your computer so it's made up of those three numbers that are either determined in red green or blue that's why they call it RGB and These values are represented in different ways Normally we see them as regular numbers or regular numbers from what we understand and that they are in decimal They're in base 10 like zero for no value 59 and green and 122 for red But there's another representation or another way we can understand and perceive these numbers That's not base 10 not in decimal But instead in hex and hex is base 16 So that counts from 0 to 0 to 15 0 1 2 3 4 5 etc until you hit 15 Our decimal counting system is base 10 It goes from 0 to 9 and then it resets at 10 right you get another digit So when we say 16 or base 16 Going to 0 to 15 is really weird right because you can't have a 15 or an 11 just hanging out as its own Number beside other numbers like we can in decimal So that's why you see those values like a and b because rather than it counting 10 11 12 13 14 15 we represent them as a through f Hex, let's see if I can Google any other representations of hexadecimal numbers Because I can give you this explanation, but until you see it. Maybe it just won't click in your mind So here's a chart right x this looks like a multiplication table Kind of huh, I guess that's just addition here. No, I don't know That's not what I want to look at. Let's look at this chart This isn't really the best background so I hope you can ignore this checkers here that's transparent But you'll see decimal in the middle column here that 10 is represented by a because we ran out of a single Character or a single digit so so to speak that we can use to represent that so a 11 is B 12 is C 13d etc and that is base 16 or 0 to 15 that's how we show it and that is just a single Value because when we look at things like RGB those values are put together in those triplets red green and blue. I Want to switch to this page. Thank you That 7a is one bite that is a binary or a Number from 0 to 255 and you can that will fill out up to 255 in decimal or go all the way to ff the notation in hex for 255 0 is Just straight up zero. There's no value there. There's nothing there So there's no blue in this color brown that we're looking at right now So let's go ahead and try some other colors if I paste these into this website looks like Did I copy the exact same color? Oh, it didn't copy to begin with classic Okay, so this is a little bit of purple mish. Maybe um, try the next one We can keep exploring these if we really want to but we can kind of do some deductive reasoning here We know that these are in pairs of red Green and blue so the zeros mean no presence of color But higher numbers all the way to ff and being 15 and 15 right in hex that means there's More of that color so c7 over here in the red Means that there's a lot of red but zero zero and zero two mean there's practically nothing Nothing for sure in green and only zero two in blue. So this must be a good red color Let's check it out. If I get over to that page Paste that in you can see okay This is basically strong red and it says that here in the description This is a hex color that's mainly red So let's go ahead and try that as our flag because they're asking for a good shade of red, right? Submit flag paste it in Submit and cool. We've got it. So that's it That is how you represent colors in hexadecimal And that's a little bit of the behind-the-scenes of looking at that data and those numbers in your computer system It's not always the zero through nine that we're used to but we can instead move on to zero through six zero through 15 in a base 16 number system So you'll see that all the time because computers like things in binary. They like it as zero in a one But you've heard stuff like eight bit computers or 16 bit 32 bit Etc. So those bits are a zero or a one and then you get maybe pairs of them or eight of them You get eight bits you get a zero Four times maybe and then a one four times maybe that's a bite and you can represent that in base 16 as those two letters like seven a or like C3 like we had seen in some of those other colors. So that's it. That's how you can represent a color by using bytes in RGB color value red green and blue sweet So now we're moving on now. We're done with the tutorial and we can jump into the real Pico CTF get into some real capture the flag challenges and jump into some cool stuff Let's learn a lot of cool stuff and let's get better at cyber security get in the capture the flag scene and baby be elite hacker All right, so we're jumping in I'm gonna go ahead and skip this so it will show us The game board here and I can explain more about this in the next video But hey before I go I do need to give a little bit of a shout out to the people that are supporting me Thank you Spencer Clark Gal Horowitz. 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