Polyalphabetic cipher | Journey into cryptography | Computer Science | Khan Academy

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  • เผยแพร่เมื่อ 8 พ.ย. 2024

ความคิดเห็น • 82

  • @JediEmil
    @JediEmil 11 ปีที่แล้ว +11

    He first tries with length 1, doesn't find the distribution he's looking for, so he tries with length 2, then length 3 and so on.
    Once he tries with length 5, he sees the distribution of english and so he knows that is the length.

  • @Crazyfor2PM
    @Crazyfor2PM 12 ปีที่แล้ว +2

    I FUCKIN LOVE KHANACADEMY! THANK GOD THAT HE LEFT HIS JOB AND DECIDED TO TEACH THE REST OF THE WORLD!

  • @hattrickster33
    @hattrickster33 6 ปีที่แล้ว +3

    You can also break this cipher by looking for repeating patterns in encrypted message. Words like "the" are so common that it is likely that you will happen to get at least 2 the's at the same distance apart as the length of the code word. When this happens, they will be encrypted in the same way, which tells you the length of the cipher.

  • @iosifpuha6114
    @iosifpuha6114 ปีที่แล้ว +1

    Is there an error at minute 0:31? If all the other letters are 19, 11 and 5 then S should be converted as 14, not 13

  • @jpmorgan187
    @jpmorgan187 11 ปีที่แล้ว +2

    Found a mistake in this video.
    N = 14th letter in alphabet, not 13th
    however, when they shifted E, they did in fact shift by 14 places.

  • @andreirocks1992
    @andreirocks1992 12 ปีที่แล้ว

    This new kind video series is just what Khan Academy was missing :)

  • @Vogel42
    @Vogel42 12 ปีที่แล้ว +2

    You are right, it should have been 14.

  • @TheStealthSage
    @TheStealthSage 11 ปีที่แล้ว +10

    I am also confused by this.

  • @SapBurough
    @SapBurough 12 ปีที่แล้ว

    Khan, this video is in your micro/macro playlist for whatever reason

  • @DeepalJayasekara
    @DeepalJayasekara 10 ปีที่แล้ว +1

    Excellent video!! Thanks :)

  • @rinyasaka2909
    @rinyasaka2909 9 ปีที่แล้ว +1

    Correction: FSFE RX (N)U PQX(C)ILSM (Y)BVJ

  • @lokynokey4822
    @lokynokey4822 11 ปีที่แล้ว +14

    I didn't get the last part. All he got was random letters. How can he determine that five was the length of the shift word from random letters.

    • @PrithaMajumder
      @PrithaMajumder 3 ปีที่แล้ว +1

      Same doubt...

    • @78anurag
      @78anurag 3 ปีที่แล้ว +1

      @@PrithaMajumder There was a common change in frequency of 5 every where

    • @SB-lh5xb
      @SB-lh5xb 3 ปีที่แล้ว +1

      @@78anurag How?

    • @78anurag
      @78anurag 3 ปีที่แล้ว +2

      @@SB-lh5xbWatch that part again and again or just stare at it, you will get it

    • @ploopyttt6536
      @ploopyttt6536 2 ปีที่แล้ว +1

      @@78anurag bro 😭😭😭

  • @Thegamemakur
    @Thegamemakur 12 ปีที่แล้ว +1

    I love learning!

  • @margar1231
    @margar1231 12 ปีที่แล้ว

    that device is classified! its usually reserved for literate people or kids who want to draw...its called paper.

  • @canutouch34
    @canutouch34 4 ปีที่แล้ว +1

    This is in the Econ playlist just an fyi

  • @thangdao5175
    @thangdao5175 12 ปีที่แล้ว

    Great video, Thanks Khan

  • @dollyandsandy
    @dollyandsandy 7 ปีที่แล้ว +4

    I don't think this video is supposed to be in the Macroeconomics playlist...?

  • @TimWarner
    @TimWarner 12 ปีที่แล้ว

    Two questions: First, what is that little device being used in the videos? And second, what is the relationship with @ArtoftheProblem whose videos are nearly identical, but with a different voice-over?

  • @chancewatkins5071
    @chancewatkins5071 10 ปีที่แล้ว +6

    This is cool, thanks for sharing these info vids; Jesus Christ Bless yall! :)

  • @Goofmobber
    @Goofmobber 12 ปีที่แล้ว

    Awesome!

  • @13rapheill
    @13rapheill 6 ปีที่แล้ว +1

    What does he mean by "shifting to the number below it"??

    • @hattrickster33
      @hattrickster33 6 ปีที่แล้ว

      Yeah they should have explained this better. It simply means adding that number to the current letter when you encrypt the message. The person you are sending it to then subtracts that number.

    • @PavanSanwlot
      @PavanSanwlot 5 ปีที่แล้ว

      @@hattrickster33bro i still didn't understand can u help me out

  • @JumboBoxGames
    @JumboBoxGames 2 หลายเดือนก่อน

    What's Khan Acedemy's theme song back in 2014?

  • @transitanalyzer313
    @transitanalyzer313 9 ปีที่แล้ว

    Please change or lower the background music. It is so high pitch that I not only cannot hear you but it is also very disturbing. It really spoiled the series for me, which are wonderful.

  • @1996sagark
    @1996sagark 12 ปีที่แล้ว

    BOMB! :*
    Truly classic

  • @saltyman7888
    @saltyman7888 11 ปีที่แล้ว

    Is it a known truth that there is no encryption algorithm that cannot be broken?

  • @someonetoogoodforyou
    @someonetoogoodforyou 12 ปีที่แล้ว

    I think you mean "did he make a mis-Snake"!! So in answer to your question, I have no idea...

  • @ddbsiblings7265
    @ddbsiblings7265 4 ปีที่แล้ว +1

    I tried clue 2 exactly as shown in this vid and I still can't get it.

  • @ThomasBaxter
    @ThomasBaxter 12 ปีที่แล้ว

    around the 1minute mark, what is the name of the device they are using to code and decode the message?

  • @PavanSanwlot
    @PavanSanwlot 5 ปีที่แล้ว

    What does he mean shifting number below it how much the gap he did to get FSFE.....
    Any one please help me out

  • @calvinhobbesliker2
    @calvinhobbesliker2 12 ปีที่แล้ว

    Wait, why is the narrator male in this video but female on ArtOfTheProblem's videos?

  • @diocholula8549
    @diocholula8549 11 ปีที่แล้ว +1

    A few mistakes on the example is ok, but not in the real world.

  • @killionaire175
    @killionaire175 5 ปีที่แล้ว

    This is biblical!

  • @andrewdomingo1653
    @andrewdomingo1653 6 ปีที่แล้ว

    Was confused by the N being 13, even if you're using a mod26 alphabet it wouldn't make much sense because shifting by 4 still wouldn't get you the right answer.

    • @rl7233
      @rl7233 2 ปีที่แล้ว +1

      "N" should be 14. It makes more sense

    • @hattydaddylive2474
      @hattydaddylive2474 2 ปีที่แล้ว

      That’s what I’m stuck on, so the video is wrong right? Being it is 14 not 13?

    • @rl7233
      @rl7233 2 ปีที่แล้ว

      @@hattydaddylive2474 that's righ

  • @ArturBSU1
    @ArturBSU1 12 ปีที่แล้ว

    wrong playlist!

  • @merinajacobson4334
    @merinajacobson4334 3 ปีที่แล้ว

    Lay man words please 🙏

  • @azadkaya
    @azadkaya 10 ปีที่แล้ว +5

    I don't get it because I get the letter N to 14 ?

  • @WarCloud20
    @WarCloud20 9 ปีที่แล้ว +3

    Heavyweight thinking.

  • @mobarakhossen2704
    @mobarakhossen2704 6 ปีที่แล้ว

    sir how could be the n is 13th number letter?

  • @BalrajArpit
    @BalrajArpit 8 ปีที่แล้ว +5

    E+13 = R not S. Please, check and respond.

  • @T3hTroll
    @T3hTroll 12 ปีที่แล้ว

    Or did he PURPOSELY DO IT?

  • @shadowranger94
    @shadowranger94 7 ปีที่แล้ว +2

    it should be 19 14 1 11

  • @hazetay
    @hazetay ปีที่แล้ว

    snakes n is wrong, it is not supposed to be 13, it is supposed to be 14...😅

  • @95cobhc
    @95cobhc 12 ปีที่แล้ว

    I didnt get it :S

  • @jvgama
    @jvgama 10 ปีที่แล้ว

    I gess this video is in the wrong playlist

    • @jvgama
      @jvgama 10 ปีที่แล้ว

      but I enjoyed it nonetheless :)

    • @njamenawilcox5612
      @njamenawilcox5612 10 ปีที่แล้ว

      Csj f's gdbdgdysyggdgghfs2westdgdgfg\"/:/ /; \,% _,%/%&5#5#%&/6\\5/\%/5:#¿♤♡♢♧》》《

    • @ploopyttt6536
      @ploopyttt6536 2 ปีที่แล้ว

      @@njamenawilcox5612 k

  • @priderock.k9s
    @priderock.k9s 4 ปีที่แล้ว +1

    8yrs later and I still don't get it.. anyone willing to explain it further??

  • @JakeOfAllTrades17
    @JakeOfAllTrades17 12 ปีที่แล้ว +1

    Saw this too. Confused me. Made me angry.

  • @StanleyZheng
    @StanleyZheng 10 ปีที่แล้ว

    Alright! Now how do I use this to help me solve clue #2?????? Even if the codeword is snake, HOW DO I DECODE IT!?!?!?

    • @LFSPharaoh
      @LFSPharaoh 9 ปีที่แล้ว +2

      if you have the length of the key, in this case it's 5, you single out each fifth letter (like at 2:07), you're now looking at a single caesar cipher, the 'juicy' data we need, the frequency of letters, can now leak out of this single cipher, you can check it against the chart at the bottom to see what the letter it could possibly be (aka determining the shift), (example: if it shows up the most it's most likely an E) but you must do this for each different letter of snake: aka 5 times. Also just thought of this, another good way to understand is, if you have a code word of all the same letter for some reason, like "EEEE" or "AAA", you now have just a caesar cipher, at least I'm pretty sure lol xD. The caesar ciphers vulnerability is frequency so the polyalphabetic cipher is a way to still use a casar cipher but use multiple different ones in the same message to soften or hide the fingerprint of the frequencies. Hope this helps if it doesn't just reply. The only way I really understand this stuff, grasp it, and ultimately remember it, is if I can help someone else do the same. :)

    • @StanleyZheng
      @StanleyZheng 9 ปีที่แล้ว

      no worries I got it now

    • @johnathanvelasquez1310
      @johnathanvelasquez1310 3 ปีที่แล้ว

      @@StanleyZheng care to help me out?

    • @StanleyZheng
      @StanleyZheng 3 ปีที่แล้ว

      @@johnathanvelasquez1310 5yo comment my friend, don't remember sorry

  • @victorgrottil5303
    @victorgrottil5303 10 ปีที่แล้ว +10

    I have no idea how to decrypt this, please tell me for fuck sake.

  • @TheOcularmigraine
    @TheOcularmigraine 12 ปีที่แล้ว

    Gnar

  • @cantugcavusoglu7656
    @cantugcavusoglu7656 9 ปีที่แล้ว

    hahah :D N for 13? you guys first learn alphabeth first before trying to deal with such things.

    • @SoldiersofGlory
      @SoldiersofGlory 9 ปีที่แล้ว

      Cantuğ Çavuşoğlu Yeah something is definitely wrong with their numbers. At first I thought N was 13 because they started counting from 0 but then that would make S 18 not 19.

  • @gravitytech
    @gravitytech ปีที่แล้ว

    first comment in two years lol

  • @Squaggerself
    @Squaggerself 7 ปีที่แล้ว

    lol khan academy screwed up

  • @lokynokey4822
    @lokynokey4822 11 ปีที่แล้ว +1

    Fuck it! Just create a new language.

  • @lokynokey4822
    @lokynokey4822 11 ปีที่แล้ว +1

    Fuck it! Just create a new language.

  • @lokynokey4822
    @lokynokey4822 11 ปีที่แล้ว +1

    Fuck it! Just create a new language.

  • @lokynokey4822
    @lokynokey4822 11 ปีที่แล้ว +3

    Fuck it! Just create a new language.