Hashing: Why & How?

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  • Опубліковано 2 жов 2024
  • Why do we wish to reduce a long list to a short one? How to do it, so that the short list will identify the long list. How to do it so that it is impossible to identify the long list from the short one, and the implications of the fact that many long lists share the very same short list. Hashing configurations: straight encryption, MD4, MD5, SHA-1, SHA-2.

КОМЕНТАРІ • 76

  • @a.a7907
    @a.a7907 7 років тому

    I liked the way you explained the points from least important to most important. I also enjoyed my time here. Definitely, I will look for more videos in this channel.

  • @walterbril630
    @walterbril630 8 років тому +27

    I am by no means (very) technical, but this is the first time I see such a clear explanation. So thank you so much!

    • @GideonTheTeacher
      @GideonTheTeacher  8 років тому +15

      +Walter Bril Thank you Walter: Explaining technical stuff to non experts in the field is very important on many levels, and is missing everywhere. I am glad I can help in that regard.

  • @behlulshaljani864
    @behlulshaljani864 5 років тому

    You simplified hashing into a sentence...thank you for this clear explanation...

  • @abdullahafridi7947
    @abdullahafridi7947 9 років тому +21

    I was searching for hash and somehow ended up here.

  • @javierlainez8376
    @javierlainez8376 9 років тому

    excellent explanation...almost give up trying to find out how it work on a simple way.

  • @fsl001
    @fsl001 9 років тому +6

    I am not a technician or engineer, however, I found the explanation very fascinating. I may have to go back a few steps though. Thank you :-)

    • @GideonTheTeacher
      @GideonTheTeacher  9 років тому +15

      +Dj Mr Cool -- you are most welcome. I try to build my explanation on common sense not on uncommon knowledge.

  • @mosesa180675
    @mosesa180675 8 років тому +1

    Hi Gideon Samid,
    it's really good and clear explanation .. i can say it's very basic flow .. fantastic job ... i am looking how HASH JOINS functionally and its behaviour work..
    i gone through Google but no luck ...
    Looking your assistance.
    Regards
    Moses

  • @sladkacokoladka
    @sladkacokoladka 8 років тому +2

    Subscribed after the first 2 minutes because of the clarity of explanation I found in this video (and later in the rest of your videos). Thank you professor! I found awesome study material on your website too.

    • @GideonTheTeacher
      @GideonTheTeacher  8 років тому +1

      +sladkacokoladka Thank you much (although I cannot decipher your name). Keeps me motivated!

  • @khaledpac7797
    @khaledpac7797 4 роки тому

    u are the best professor.....i like ur method to explain the problems....thank you very much professor

  • @thecuriousone12
    @thecuriousone12 8 років тому +1

    First video I've seen of yours and I subscribed within the first minutes. Very clear explanation, thank you!

  • @fireeye33
    @fireeye33 6 років тому

    I love this video thank you so much!!

  • @danielalt7508
    @danielalt7508 6 років тому

    13:55 Why do we use blocks instead of every character its own block or have one long string hashed itself many times?

  • @salaheamean
    @salaheamean 10 років тому +2

    I like the way u initiated your presentation.It is an experience.
    Thank you sir

    • @GideonTheTeacher
      @GideonTheTeacher  8 років тому

      +salahe amean -- thank you! Glad it was useful for you!

  • @educationmadeeasy6420
    @educationmadeeasy6420 10 років тому +3

    Wonderful explanation shalom to you

  • @JohnSmith-he5xg
    @JohnSmith-he5xg 8 років тому

    Great point that collisions are unavoidable (and can only be made more difficult to find) given that we are taking an input of size S and trying to represent it in a smaller size L.

  • @mouradbarakat123
    @mouradbarakat123 7 років тому

    Thanks for the video.
    I have one comment about what you said on information theory, that a short list cannot contain all the information about the long list, just because it's shorter, that is not correct. For example, a compression algorithm can reduce the size of a big list into a smaller one without any loss of information, then a decompression algorithm can reproduce the original list again.

  • @hattube
    @hattube 6 років тому

    Question: does " implications of the fact that many long lists share the very same short list" mean that there are already collisions we don't even know about?

  • @kfudub7254
    @kfudub7254 9 років тому

    Thanks for the video. One question: A hash (like SHA-256) could be used to copyright? Like a song? If the SHA256 of the file (mp3) + date, this could be used in a certificate?

    • @GideonTheTeacher
      @GideonTheTeacher  8 років тому

      +Kfu Dub yes, it could, but you need a trusted party to carry out the hash.

  • @burhanhassan4377
    @burhanhassan4377 8 років тому

    Hi,nice explanation. Can you please name encryption protocols having cipher size greater then plain text size. 😊

  • @MrBahaaeldinmohamed
    @MrBahaaeldinmohamed 6 років тому

    very detailed explanation I hope if I can get more videos related to the cryptography topics
    Thanks too much

  • @anjalirai7127
    @anjalirai7127 5 років тому

    I was going through hashing concepts, and this was a clear and crisp good explanation. Thank you

  • @RSTao77432
    @RSTao77432 6 років тому

    Are Salts stored on the local machine? As there not stored in the database??

  • @roseb2105
    @roseb2105 8 років тому

    sorry Just clarifying the point of cypher is to condense the text so that if we have limited spots available we have less chance of multiple data parts sharing the same spot and therefore avoiding collision? Also I like the way this lecture is presented would you mind making a video on how the polynomial has function works?

    • @GideonTheTeacher
      @GideonTheTeacher  8 років тому

      +Rose B
      Thank you Rose, if I find time, will upload the requested video.

  • @AlrightIamdone
    @AlrightIamdone 8 років тому

    awesome sir searched across google..found uh the best ....

  • @krantikumar2709
    @krantikumar2709 8 років тому

    Thank you sir for your beautiful explanation. Super.

  • @bestforgebuilder
    @bestforgebuilder 9 років тому

    I dont know what it is about your presentations but these help me understand so well. I especially appreciate how you build the foundation first and work from there. Great lecture

    • @GideonTheTeacher
      @GideonTheTeacher  9 років тому

      Thank you bestforgebuilder, I am really glad that you absorb it all so well!

  • @gkuhgjgh
    @gkuhgjgh 7 років тому

    Very nice Prof Gideon. Its very nice tutorial.

  • @pragadheshwarankulandhaive6466
    @pragadheshwarankulandhaive6466 10 років тому

    nice explanation sir!,,,u did well in this video,,and thanks

  • @tucom3556
    @tucom3556 8 років тому

    i need to see some lectures abut minhash and minhash types please

  • @terryburke7605
    @terryburke7605 9 років тому

    Thank you. Very informative

  • @eliotsalinas7504
    @eliotsalinas7504 7 років тому

    Thank you for the simplicity.

  • @adon2424
    @adon2424 6 років тому

    Lost me at l to the e. Poor delivery.

  • @DioXin
    @DioXin 9 років тому

    Thank you prof. ! Toda Raba! :-)

  • @kalyanhr
    @kalyanhr 7 років тому

    Awesome explanation Sir.

  • @RedShipsofSpainAgain
    @RedShipsofSpainAgain 8 років тому

    5:40 You're talking about the pigeonhole principle here, correct?

    • @pr1493
      @pr1493 8 років тому

      he ain't using pigeonhole principle here.. he's just applying the hash function to get a fixed size hash value of s bits, say for l bit block of data.

  • @mediel6378
    @mediel6378 6 років тому

    Loved your explanation

  • @GiveItNowX
    @GiveItNowX 9 років тому +1

    Thank you Sir!

  • @DevendraSingh-uz2wk
    @DevendraSingh-uz2wk 6 років тому

    Thanks a lot!! 👏👏👏👏
    #Gideonsamid sir

  • @naresh1234nmnn
    @naresh1234nmnn 9 років тому

    very very good explanation . I salute you sir ji.

  • @Makerbreaker10
    @Makerbreaker10 7 років тому

    This sir looks like Walter white😂

  • @abdulblessinger6659
    @abdulblessinger6659 8 років тому

    lol - catch a few hi lights

  • @AliOpridai
    @AliOpridai 9 років тому

    Finally I get it!
    Thank you!

  • @shaniranshul
    @shaniranshul 6 років тому

    Nice, short & effective

  • @STPADDYSHUGOSPLAY
    @STPADDYSHUGOSPLAY 9 років тому

    great explanation! thanks!

  • @GiangPham-mg3vd
    @GiangPham-mg3vd 8 років тому

    thank you sir! thanks a lots!

  • @tejara01
    @tejara01 7 років тому

    wtf is with the clicking...

  • @QuantumDataInc
    @QuantumDataInc 7 років тому

    This guy is great.

  • @walkingbobblehead
    @walkingbobblehead 10 років тому

    2 advanced 4 me
    salami 2 u

  • @zachdems4634
    @zachdems4634 7 років тому

    How can we get a cryptocurrency backed by anything

    • @GideonTheTeacher
      @GideonTheTeacher  7 років тому

      check out bitmint.com, or the book "Tethered Money: Managing Digital Currency Transactions" available on Amazon (Elsevier 2015), including digital edition.

  • @bmurph24
    @bmurph24 9 років тому

    Much appreciated.

  • @MUHAMMADUMARASHRAFBCS
    @MUHAMMADUMARASHRAFBCS 7 років тому

    Excellent Explaination.......

  • @saumya8149
    @saumya8149 6 років тому

    Awesome

  • @qassemaleid9774
    @qassemaleid9774 7 років тому

    thank you

  • @ecapanema
    @ecapanema 7 років тому

    bitcoin is not based on sha-2 but on sha-256

  • @eldadmo
    @eldadmo 10 років тому

    You are great! Toda raba!

  • @abdullgoes
    @abdullgoes 9 років тому

    thank u

  • @jacobkurien
    @jacobkurien 8 років тому +1

    you sir are a legend

    • @GideonTheTeacher
      @GideonTheTeacher  8 років тому +8

      Thank you Jacobkurien. I am not a legend, but I think the world will be a better place if we learn to explain better. Clarity prevents mistakes and misuse.

    • @doctorlazarus8854
      @doctorlazarus8854 7 років тому

      Gideon Samid You, sir, are very humble! :)