Public key cryptography - Diffie-Hellman Key Exchange (full version)

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  • Опубліковано 29 лип 2012
  • The history behind public key cryptography & the Diffie-Hellman key exchange algorithm.
    We also have a video on RSA here: • Public Key Cryptograph...

КОМЕНТАРІ • 625

  • @dancarlson3045
    @dancarlson3045 8 років тому +557

    The color analogy is amazing. Great work simplifying a difficult and important concept.

    • @human.earthling
      @human.earthling 7 років тому +14

      Yes! This is the first time I have understood this concept due to the color analogy.

    • @1986xuan
      @1986xuan 6 років тому +6

      Analogies are so powerful

    • @jacquelinecahill4836
      @jacquelinecahill4836 6 років тому +2

      I really enjoyed this. Thanks for breaking it down.

    • @Percavius
      @Percavius 5 років тому +2

      It's good in that it's simple, however unlike the discreet logarithm problem, you would be able to make a good estimate of the secret colour based on the starting colour and one of the mixed colours. For example if Eve received the starting colour yellow, and a mixed colour green, she can infer that the secret colour mixed in must be some shade of blue, which makes her search much easier. Recognizing this threw me off a bit at first.

    • @jsonkody
      @jsonkody 4 роки тому

      The concept is simple and genius.

  • @ChristopherCricketWallace
    @ChristopherCricketWallace 8 років тому +297

    by far the best explanation of public key encryption EVER.

    • @ArtOfTheProblem
      @ArtOfTheProblem  3 роки тому +5

      thanks for watching! stick around

    • @lennonmclean
      @lennonmclean 3 роки тому +5

      unfortunately, public key is completely different than key exchange. public key requires different keys to encrypt and decrypt, so there's no need for diffie hellman to agree on a secret key.

    • @ArtOfTheProblem
      @ArtOfTheProblem  8 місяців тому

      made another vid: ua-cam.com/video/OFS90-FX6pg/v-deo.html

  • @albertoradice7713
    @albertoradice7713 8 років тому +16

    This is precisely how mathematical concepts should always be explained. You guys nailed it!

    • @ArtOfTheProblem
      @ArtOfTheProblem  8 місяців тому

      would love your feedback again ua-cam.com/video/OFS90-FX6pg/v-deo.html

  • @wilkmasterflex
    @wilkmasterflex 12 років тому +71

    A great illustration. Diffie-Hellman has a well-known, fun vulnerability. Spoilers: Eve, knowledgeable herself on color theory, intercepts messages between Alice and Bob not letting their messages go directly to them. Instead she creates a color of her own. Mixing it twice with each of Alice and Bob's colors she creates two keys. She can now read Bob's message, re-encrypt, and send to Alice and pose as Bob. Same goes in the other direction. If only Alice could trust Bob's color comes from him.

    • @Germanywithtripti101
      @Germanywithtripti101 3 роки тому +4

      an underestimatted comment

    • @Arkalius80
      @Arkalius80 3 роки тому +5

      This is why you typically use a digital signing algorithm like DSA to authenticate the messages from each party.

    • @lennonmclean
      @lennonmclean 3 роки тому +5

      if only (epic RSA foreshadowing)

    • @alittax
      @alittax 2 роки тому +10

      This is called the man-in-the-middle attack.

    • @AnimMouse
      @AnimMouse 2 роки тому +1

      Key signing parties!

  • @satnamo
    @satnamo 7 років тому +74

    Martin Hellman said:
    The system...has since become known as Diffie-Hellman key exchange.
    While that system was first described in a paper by Diffie and me, it is
    a public key distribution system, a concept developed by Merkle, and
    hence should be called 'Diffie-Hellman-Merkle key exchange'
    if names are to be associated with it. I hope this small pulpit might help in that
    endeavor to recognize Merkle's equal contribution to the invention of
    public key cryptography.

  • @AjayPoriya
    @AjayPoriya 7 років тому +175

    I nominate this video for OSCAR !!

    • @barbell13
      @barbell13 7 років тому +10

      Yeah Oscar would definitely like this video

    • @alice_in_wonderland42
      @alice_in_wonderland42 5 років тому

      Computerphille uses the same technique.

  • @SomeOne-tb2sd
    @SomeOne-tb2sd 3 роки тому +1

    One the best and simplistic explanation of what appears to be a complex algorithmic process. Thank you.

  • @Nefariouspat
    @Nefariouspat 7 років тому +3

    I've watched a few videos on public key cryptography, but never really understood how it worked until I heard this colour analogy. Absolutely phenomenal video!

  • @199NickYT
    @199NickYT 10 років тому +46

    "While Eve is stuck grinding away at the Discrete Logarithm Problem"
    Hahaha that's definitely the best part right there.

  • @xetronchan1059
    @xetronchan1059 6 років тому

    Most amazing and simple and clean explanation of Diffie-Hellman algorithm I've came across. Great!!!

  • @wreilly09
    @wreilly09 2 роки тому

    THIS DID IT!! You helped me understand a few points that, in my opinion, we’re not pearly presented in other videos. Thank you very much.

  • @davidcalderon6062
    @davidcalderon6062 7 років тому +12

    this is the best explanation I've seen on anything.

  • @ninumedia
    @ninumedia 9 років тому

    Thank you for taking the time to record and produce this video! Beautiful explanation.

  • @jasoncorrigan9937
    @jasoncorrigan9937 6 років тому +7

    My background in advanced math concepts is somewhat limited, and so it's always been difficult for me to intuitively grasp how DH worked. After years of struggling, this is the one video that really drove the point home for me. Thank you!

    • @oliverbeck6839
      @oliverbeck6839 5 років тому +1

      dafuq YEARS? i grasped it in about 15 minutes lol

  • @SanjayShelat
    @SanjayShelat 5 років тому

    This is an excellent explanation of what is usually a difficult issue to understand. Thank you!

  • @appapurapu
    @appapurapu 8 років тому +5

    Brilliant trick behind Diffie Hellman explanation is very clear.
    Thanks a Lot.

  • @marelloeg6988
    @marelloeg6988 4 роки тому

    Videos like this are always remind me why I am fascinated about the cybersecurity field! This is a fantastic video!

  • @aymanjabali
    @aymanjabali 4 роки тому

    Thank you sooo much for putting time and work into this video.
    you've helped a lot of people around the world

  • @mmuarc
    @mmuarc 4 роки тому

    Best explanation you can find on the internet about this. The color analogy is Godlike

  • @dm8144
    @dm8144 3 роки тому +1

    I am typing typing this message in 29/10/2020 and this is one of the best and easiest explanation about public and private key system ever. well done.

  • @AkashVermaNITian
    @AkashVermaNITian 9 років тому +13

    Colors made it wonderful to comprehend... really impressing!

    • @ANTHONYBOOTH
      @ANTHONYBOOTH 9 років тому

      Akash Verma now. I think that I understand how my Gizmo (for online banking) from HSBC works........

    • @Appoxo
      @Appoxo 3 роки тому

      I actually needed the numbers to kinda grasp the concept...

  • @rschintalapati
    @rschintalapati 8 років тому +1

    Amazing explanation! The best video about DH Algorithm. Thank you, it really helped me a lot.

  • @roxiogamer
    @roxiogamer 7 років тому +1

    Oml dude this is exactly what I have been looking for! A visual explanation on how it works ! 10/10

  • @skidude9800
    @skidude9800 5 років тому

    Single best explanation on any cryptography concept I've seen.

  • @Malmizaur
    @Malmizaur 8 років тому +143

    wow finaly the video i was looking for with the best explanation and number proving examples
    thank you very much I also checked your chanel realy awesome

    • @ArtOfTheProblem
      @ArtOfTheProblem  8 років тому +12

      +Malmizaur Episode 3 is up next: ua-cam.com/video/4qN9OvvEPr8/v-deo.html

    • @dangerlibya2010
      @dangerlibya2010 7 років тому

      you are a magician !

  • @MohamedAnsari_H
    @MohamedAnsari_H 7 років тому +4

    fantastic video, explained something I've wondered for a long time, Thank you.

  • @mash0000
    @mash0000 8 років тому

    Use of mixing colors as an analogy to explain the DH concept was brilliant. I know DH concept well, but never thought of the color analogy. Good job!

  • @duallancers001
    @duallancers001 8 років тому

    This was dramatically more helpful than the meager amount of info my book offered on the subject; thank you.

  • @blackmouthblackface
    @blackmouthblackface 8 років тому

    Much better than the short version which confused the hell outta me @4:35!
    Thank you very much for posting this!

  • @kanaverum
    @kanaverum 7 років тому

    Perhaps the best explanation of private key exchange on the internet. Thanks very much for this video!

  • @supernanotech1
    @supernanotech1 3 роки тому +1

    Time hardened Encryption just like safe hardening how much time is needed to open it. I love this, this is the best way to explain encryption ever. I love how they have IBM sage running for this video also. Amazing

  • @davidr.flores2043
    @davidr.flores2043 4 роки тому +3

    Fantastic. I've watched many videos on this same topic; nevertheless, this is The Best one. A million thanks for breaking down difficult concepts in an easy, understandable way. Kudos!

    • @ArtOfTheProblem
      @ArtOfTheProblem  4 роки тому +1

      appreciate the feedback. I always watch every video on a topic before making a new one, so i'm glad you noticed :)

  • @KILO993
    @KILO993 7 років тому

    I found your video while studying for a technical certification. Very well done. Thank you :D

  • @orionjonesy226
    @orionjonesy226 8 років тому

    Thank you for making this video, great explanation and brief history of the concept! Keep on, keeping on!

  • @jon_hodl
    @jon_hodl 9 місяців тому

    Still one of the absolute best videos for explaining asymmetric key pair encryption

  • @KautilyaSave
    @KautilyaSave 8 років тому

    Great video explanation. I loved the demonstration of colors & Mod Calculus Clock rope.

  • @jacquesvanderwesthuizen7287
    @jacquesvanderwesthuizen7287 9 років тому

    Very well explained. I would recommend this video to anyone studying the arts of encryption/decryption.

  • @IAmSinister5
    @IAmSinister5 7 років тому

    This is such a good explanation, it makes so much sense logically to me now.

  • @notmychairnotmyproblem
    @notmychairnotmyproblem 3 роки тому

    THIS IS THE EASIEST EXPLANATION OF MODULAR MATH I'VE EVER SEEN
    Why didn't I have this channel 10 years ago when I was in college??!!

  • @mfratto
    @mfratto 7 років тому +3

    That's called magic math. Great video. Very helpful. Now to watch the series.

  • @akshaymahale6521
    @akshaymahale6521 8 років тому

    It was just awesome, u played wid the colors and dat made the algo go so simple to understand !!!

  • @thomaspribitzer5373
    @thomaspribitzer5373 6 років тому

    that colour analogy was mind blowing. made my day!

  • @LGM4
    @LGM4 7 років тому

    LOL I've been explaining this idea using colors for about 6 months, then I find your video! love it!

  • @georgiepentch
    @georgiepentch 4 роки тому +3

    Oh my god, your content would fit SO WELL into a podcast format! It's something we need!

    • @ArtOfTheProblem
      @ArtOfTheProblem  4 роки тому +2

      Funny you say that, i'm working on developing a podcast right now. I was town between just using the audio from these or doing a new conversational approach. can you listen to the demo I posted last week and give feedback? ua-cam.com/video/1w4Y_sCDeCE/v-deo.html

    • @georgiepentch
      @georgiepentch 4 роки тому

      @@ArtOfTheProblem wow sorry, I don't know why I just got this notification now, but I did listen to the demo and I loved it! Keep it up :)

  • @Yashuu96
    @Yashuu96 7 років тому +1

    This video is so awesome! Had been looking for the answer to this problem.

  • @CrazyDoBlue_1
    @CrazyDoBlue_1 9 місяців тому

    I really really like the music in this video. It mysterious. I like the fact that you take your time to explain and it is also visual. Nice creative video.

    • @ArtOfTheProblem
      @ArtOfTheProblem  8 місяців тому

      Took 2 years to finish this one, finally live would love your feedback: ua-cam.com/video/OFS90-FX6pg/v-deo.html

  • @MalaAnsoo
    @MalaAnsoo 4 роки тому

    This is ingenious. Thanks for sharing your knowledge and creativity and helping people to understand so easily.

    • @ArtOfTheProblem
      @ArtOfTheProblem  4 роки тому

      appreciate the feedback and comment, stay tuned!

  • @tasoskontos10
    @tasoskontos10 5 років тому

    Great video! It helped me an insane amount understanding the public key cryptography consept.

  • @greg4529
    @greg4529 8 років тому +2

    Amazing and excellent explanation. Better than my lecturer!

  • @ashutoshnautiyal9625
    @ashutoshnautiyal9625 5 років тому

    this kind of learning material is actually i m looking for. Great explanation
    .

  • @houyao2147
    @houyao2147 5 років тому

    Amazing!!!! This is the best explanation that i've ever seen.

  • @mortenbrodersen8664
    @mortenbrodersen8664 6 років тому

    Best explanation I have ever seen. Well done!

  • @blackcheetah4550
    @blackcheetah4550 4 роки тому

    The best explanation on UA-cam .. thank you very very much ❤️❤️

  • @wassollderscheiss33
    @wassollderscheiss33 9 років тому +18

    I love it! (this is the first thing I publicly love on the internet) :-)

    • @ArtOfTheProblem
      @ArtOfTheProblem  9 років тому +2

      wassollderscheiss33 That's so awesome. Thanks for the love

  • @scienceblossom6197
    @scienceblossom6197 6 років тому

    Can't thank you enough. Awesome video. I wish you also explained how the digital signature works in order to avoid Eve pretending to be either Bob or Alice.

  • @nabeel250575
    @nabeel250575 11 років тому

    This is really a great set of videos. Thanks and great work.

  • @danyellbaptiste1055
    @danyellbaptiste1055 5 років тому +3

    EXCELLENT EXPLANATION. Thank You!

  • @laurv8370
    @laurv8370 6 років тому +8

    Very nice! Hat off! One of the best explanations I have seen, and nice put into the story. however, when you swap those powers, you should use parenthesis, that is because generally, powering is not commutative. That is, a^b^c is not equal to a^c^b, modular or non modular powering. Powering is right-associative. But (a^b)^c=a^b*a^b*...a^b (c times) which is a^(b*c)=a^(c*b)=a*a*a*a.... (b*c times), which is (a^c)^b always, modular or not. This is due to the commutativity of the _multiplication_ operation. Not the powers.

  • @exdunn
    @exdunn 7 років тому

    I learned more from this video than 5 weeks worth of lecturing in my university class.

  • @CarlitoProductions
    @CarlitoProductions 5 років тому +1

    if this was 2 hours, i'd still watch it. awesome explanation

  • @ROCDUC
    @ROCDUC 11 років тому

    Your videos are great. They have interesting visuals as well as an easy voice to listen to.

  • @fubonte2272
    @fubonte2272 7 років тому

    why can't i like this video more than once? thank you for an excellent explanation

  • @johnmacward
    @johnmacward 9 років тому

    Brilliant explanation about key exchange for those of you interested in how your data is encrypted over the web. Ok, when the maths comes you need to pay attention but all in all the best explanation I've found.

  • @godfreytan1001
    @godfreytan1001 7 років тому

    Deep concept but simply explained. Excellent!

  • @atom2ueki
    @atom2ueki 10 років тому

    definitely an awesome video show you how to understand Diffie-hellman key exchange

  • @thefirstfishadvancetheland8980
    @thefirstfishadvancetheland8980 7 років тому

    This is so beautiful theory. Really amazing!! Thank you for showing:)

  • @Konraden
    @Konraden 11 років тому

    I'm reading wiki trying to understand how public-key encryption works (I'm told its better than symmetrical encryption). I remember someone tried to explain this before using colors, so a quick search--and I find your video. This is a great video.

  • @jackdrost7291
    @jackdrost7291 6 років тому

    Excellent explanation of a hard thing to understand. Thank you! (Cool background music too!)

  • @abeer_nawaf_sul
    @abeer_nawaf_sul 8 років тому

    very smart.. my teacher also explained it in a wonderful way so it stuck in our minds .. bless him

  • @sics993
    @sics993 10 років тому

    Really good explainded. Helped me a lot, thank you for making this!

  • @princyep8409
    @princyep8409 7 років тому +1

    The articulation is excellent! Great read

  • @infinitybiff
    @infinitybiff 7 років тому

    well this was an incredible video. such a good explanation. well done!

  • @fireflies15
    @fireflies15 2 роки тому

    "without letting Eve, who's always listening.."
    brilliant video, amazing explanation
    thank you!

  • @AgglomeratiProduzioni
    @AgglomeratiProduzioni 7 років тому

    For a few months, my teacher didn't manage to explain this to a class.
    In 8 minutes, this video can explain it to every dummy.
    If it's simple, keep it simple.

  • @TheLexusAlexey
    @TheLexusAlexey 3 роки тому +1

    I just love this, everything is so much easier!

  • @mustafarangwala5657
    @mustafarangwala5657 8 років тому

    Very nice i was thought about the color logic in my college but i wondered how it would work in numbers.Excellent video.

  • @redrover06able
    @redrover06able 9 років тому

    Great video. I like the intro and examples used.

  • @piriyaie
    @piriyaie 7 років тому

    AWESOME!!!! Please keep on teaching... You did a great job!!!

  • @earavichandran
    @earavichandran 4 роки тому +1

    Now i understand clearly about diffe Hellman method. Lovely and lively demo video. Thanks for making this wonderful video.

    • @ArtOfTheProblem
      @ArtOfTheProblem  4 роки тому +1

      thanks please share and stick around for more content.

    • @earavichandran
      @earavichandran 4 роки тому

      @@ArtOfTheProblem yes.thanks for your valuable reply.

  • @ma271
    @ma271 6 років тому

    Dude thank you. Really a great video

  • @mort8568
    @mort8568 4 роки тому

    I'm not even a math guy or even like numbers that much but every once in a while I come back to this video purely because of how entertaining it is

  • @h.kkhandelwal9142
    @h.kkhandelwal9142 9 років тому

    Lovely videos. .... awesome way of descriptions. .... awesome job.... very well done guys

  • @valor36az
    @valor36az 5 років тому +5

    I don’t know what your background is just amazing explanation of concepts

    • @ArtOfTheProblem
      @ArtOfTheProblem  5 років тому +3

      I did a degree in CS and Engineering however I've always enjoyed explaining things. thanks for the feedback

  • @SninjaThirteen
    @SninjaThirteen 8 років тому

    Thank you so much. Really helped me understand the concept. And I thought I was just going to have to fail my certification exam.

  • @AmanShaikh-qr5lh
    @AmanShaikh-qr5lh 5 років тому

    That's a wonderful example!!! Mind blowing 😍😍😍

  • @gowthamiirao9010
    @gowthamiirao9010 8 років тому

    Very well explained. Thanks a tone for your effort.

  • @andyGPT101
    @andyGPT101 9 років тому

    Nicely done. Makes a lot of sense

  • @carlossiverio3570
    @carlossiverio3570 Рік тому

    This is the best explanation by far.

  • @chetanrane724
    @chetanrane724 6 років тому

    fantastic explanation. loved it

  • @ishaanvyas1490
    @ishaanvyas1490 7 років тому

    Really helpful and very interesting..thank you very much.😁😄 it helped me in my exam...it is tomorrow by the way😋
    please can you do more videos..on like Rc6,Fiestel structure,Aes,Des,ceasar cipher,etc.
    but please don't stop making videos..keep doing it. We really appreciate it.
    thank you soo much again.

  • @ImmaShadowGirl
    @ImmaShadowGirl 7 років тому +1

    Thanks a lot! This was amazing!

  • @Kevi_N.
    @Kevi_N. 8 років тому +25

    The trick in a nutshell:
    ( G^*a* mod P )^*b* mod P = G^*a*^*b* mod P = ( G^*b* mod P)^*a* mod P = *key*
    *a* and *b* - private numbers
    *key* - private key (same for both)
    G - public generator
    P - public prime module
    ( G^*a* mod P ) = *A*
    ( G^*b* mod P) = *B*
    *A* and *B* - public numbers
    both sites do:
    *A*^*b* mod P = *B*^*a* mod P = *key*

    • @yc4295
      @yc4295 7 років тому

      I try to calculate in Javascript but found it not the same, is there any wrong?
      According to the fomula "( G^a mod P )^b mod P = G^a^b mod P",
      Assume G = 3, a = 13, P = 17, b = 15
      Math.pow(Math.pow(3, 13) % 17, 15) % 17 = 10
      Math.pow(Math.pow(3, 13), 15) % 17 = 2
      Math.pow(Math.pow(3, 15) % 17, 13) % 17 = 10
      But 10 is not equal to 2

    • @romanmandeleil
      @romanmandeleil 7 років тому

      Not clear how A^b = B^a

    • @uid26
      @uid26 6 років тому

      Paste this into console: Math.pow(Math.pow(3,15)%17, 13)%17
      Result should be 10

  • @ankitprajapati3768
    @ankitprajapati3768 7 років тому

    Great job! Very good explanation.

  • @JohnGodfrey
    @JohnGodfrey 7 років тому

    Thanks, best I've seen on this. :-)

  • @hdlopesrocha
    @hdlopesrocha 2 роки тому

    Cryptography 101, the best intro ever!

  • @legoman777777777
    @legoman777777777 8 років тому

    Awesome! Thank you! Great job guys

  • @upliftingspirit6873
    @upliftingspirit6873 5 років тому

    I seriously love this video.

  • @aiayumi
    @aiayumi 6 років тому

    Amazing you fully explained this using paint!

  • @Derbauer
    @Derbauer 5 років тому

    Just......beautifully and succinctly explained!

    • @ArtOfTheProblem
      @ArtOfTheProblem  5 років тому +1

      thanks for the feedback, stay tuned for more

  • @frank4738
    @frank4738 6 років тому

    Great video, clear explanation. Thanks