The Data Encryption Standard (DES) Cipher Explained - How Does it Work?

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  • Опубликовано: 1 фев 2025

Комментарии • 9

  • @creonte38
    @creonte38 4 года назад +4

    Horst Feistel created the most elegant way to do encryption. Thanks for the video. I would like to know if you will approach Thorp Shuffle(Feistel network unbalanced) in the future?

    • @CryptographyForEverybody
      @CryptographyForEverybody  4 года назад +3

      Hiho, the next videos (about modern ciphers/cryptography) that I want to make are probably about AES, and then some hash functions (MD5, SHA-1, SHA-256). Also, I will have a look at more modern techniques in the future, but since this is not my main expertise I have to first get more knowledge about such topics :-)

  • @l.w.8313
    @l.w.8313 4 года назад +3

    Thank you for this video - great explanation! Only one thing I noticed: Around 8:35 you are showing the structure of the DES rounds. In the last round you are applying the feistel function + XOR again to L_16 and R_16. I had a look at the specification and could not find this last operation. Did I miss something here?

    • @CryptographyForEverybody
      @CryptographyForEverybody  4 года назад +2

      Hello L.W.,
      Yes, you are right. In the last step of the figure, it should have been L_15 and R_15. And the results are L_16 and R_16. Good catch.
      Funnily, I implemented DES before creation of the video :-) but obviously added the wrong indices at the end.
      In the end is also no crossover of left and right. That is shown correctly.
      Greetings,
      Nils

  • @abhijeetkarna3229
    @abhijeetkarna3229 2 года назад

    In video at (16:39 slide 6) I think the initial key is size of 64 bit and the size of Permuted Choice 1 should be 56-bits

    • @CryptographyForEverybody
      @CryptographyForEverybody  2 года назад

      Hiho,
      Yes you are right.
      The input key size of DES is 64 bit. But only 56 bit are used as actual key material. The remaining "unused" 8 bits are used as parity bits. So every 8th bit is a paritiy bit.
      Greetings,
      Nils

  • @afifahmu
    @afifahmu 3 года назад +2

    hello, that's a great video! What should i do when i want to encryption URL with DES algrithm in cryptool?

    • @CryptographyForEverybody
      @CryptographyForEverybody  3 года назад

      Hello Afifah Muthmainnah,
      If you want to encrypt text (and a URL is also just text, I suppose :-)) you can try encrypting it as described in this video here: ruclips.net/video/Ie7yg1okghk/видео.html
      In the video, I use AES for encrypting text, but you could just exchange the AES component with a DES component. Nevertheless, I would suggest using AES since its the current encryption standard and DES is outdated.
      Hope that helps and answers your question,
      Greetings,
      Nils

    • @afifahmu
      @afifahmu 3 года назад

      what is the difference between encrpting endpoint URL using the AES algorithm and the Rijndael algorithm? where can we find the rijndael algorithm in cryptool?