Thursday, 10 March 2011

Cryptography and Cryptanalysis: Atbash Cipher

The Atbash cipher is a very old substitution cipher. (A substitution cipher is when you substitute one letter or word with another.) Hebrews scholars used this code for biblical text. Basically you substitute the last letter with the first and the second with the second last letter.

Example: A would be substituted with Z, B with Y, U with F, P with K...

It is a very weak cipher because it only has one possible key, and it is a simple monoalphabetic substitution cipher.



Try solving this code:
Dszg rh blfi uzelirgv xlwv-yzhvw nlerv?

29 comments:

  1. That was fun, "what is your favorite code-based movie?" A movie doesn't come to mind, but I just finished listening to the audio book of THE CAT WHO CAME TO BREAKFAST by Lilan Jackson Braun and it had a code in it.

    Mason
    Thoughts in Progress

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  2. I presume one of those Angel and Demon movies but I guess my mind is blank. :)

    Have you seen this show? There is a really good episode on Jefferson and his use of codes.
    http://www.history.com/shows/brad-meltzers-decoded

    Have a good one :)
    Jules @ Trying To Get Over The Rainbow

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  3. You always come up with fun brain teasers, Clarissa.

    Michael

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  4. Mason, I haven't heard of it but I want to read it now!

    LB, that's such a cool movie!

    Jules, I'm going to check it out.

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  5. Star Trek!! I'm sure they had a code breaker thingy in one of their films! LOL! Take care
    x

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  6. Star Trek!? LOL. I've not watched enough to know.

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  7. Clarissa - Thanks! This is really interesting! I have to admit, I'm not all that much of a movie-goer, so answering your question would be hard. But I liked the code in Dorothy Sayers' Have His Carcase.

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  8. I just read Juliet and that had some coding in it...I got what she was saying, but if she didn't walk me through it, there was no way I would have known. I do like the Dan Brown type of movie.

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  9. That's easy once you get the hang of it.

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  10. Interesting! I never had the patience to do any of this decoding stuff, but I do find it fascinating.

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  11. Awesome code stuff! I really like The Da Vinci Code.

    By the way, I used to do those cryptograms a lot. They are always fun to figure out the code. I hadn't heard of the Atbash Cipher before, though. Great post!

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  12. Codes are cool. I remember the movie Sneakers had a device that cracked all codes.

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  13. I love cryptography. It's such a fascinating subject - the more you delve the more weird things you can find out. But then I just love all things spy!

    My answer - I guess the Da Vinci Code.

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  14. Of course, no movies come to mind. I remember creating codes with my friends when I was little. It was so much fun.

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  15. The Matrix.
    It always amazed us when the teachers knew what we wrote. LOL

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  16. You have discovered my weakness. I have trouble with cipher's and I also have trouble telling when people are lying. I value honestly above almost everything else. This is why I can't write mysteries. I am no good at it.
    Nancy
    N. R. Williams, The Treasures of Carmelidrium, Special .99 through April 30

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  17. As I taught one of my classes a couple of years ago, this type of cipher is far too simple :D

    If the text is long enough, it is easy to see which letters and combinations occur most often.

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  18. Margot, I will have to read Dorothy Sayers' Have His Carcase. Thanks!

    Carolyn, cool! Another book suggestion. I'll look up Juliet.

    L. Diane, yeah. Anything with practice.

    Talli, glad you liked it.

    Cherie, atbash is a type of cryptogram.

    Alex, I loved the movie Sneakers! I'll have to watch it again. I liked the part where he was in the trunk but could find his way but the sounds alone.

    Kate, me too! I'm studying it a lot.

    Holly, I used to do that as a child. Kinda like a scavenger hunt.

    Mary, that's funny!

    Nancy, personally, I think people who can't read others are fortunate because I hate knowing how others are feeling all the time. It makes me want to hid in my house.

    Dorte, I agree. It's one of the most simple. What class did you teach?

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  19. I love codes. Would National Treasure fit into that?

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  20. I don't know . . . I recently watched The Da Vinci Code but I wouldn't say it's my favorite code-based movie. Then again, I haven't really seen that many. :P

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  21. Excellent brain teaser! It certainly had me stumped.

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  22. "cipher" - I've just learned a new English word :)

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  23. whoo, ghirl. I don't usually do cypers b/c they're hard! LOL! But I like learning about them and the histories and how they were used. Cool... :o) <3

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  24. I don't have a favorite, but I sure liked this post! I think I'm going to run off and cause some mischief with code now. :P

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  25. Late to the party, but I agree with some of the others. The Matrix is awesome!

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  26. Interesting post Clarissa. My oldest son has dreams of finding lost treasure and what better topic to hold his attention that the famous uncracked Beale Ciphers.

    Too bad there is no movie about it so I could answer your question.

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  27. hmmm, code-based movie, huh?? Let me think on that...

    Probably Mercury Rising. I love me some Bruce Willis.

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