- Atbash
Atbash is a simple
substitution cipher for theHebrew alphabet . It consists in substituting "aleph " (the first letter) for "tav" (the last), "beth" (the second) for "shin" (one before last), and so on, reversing thealphabet . In theBook of Jeremiah , nowrap|לב קמי "Lev Kamai" (51:1) is Atbash for nowrap|כשדים "Kasdim" (Chaldeans ), and nowrap|ששך "Sheshakh" (25:26; 51:41) is Atbash for nowrap|בבל "Bavel" (Babylon ). It has been associated with the esoteric methodologies ofJewish mysticism 's interpretations ofHebrew religious texts as in theKabbalah .An Atbash cipher for the
Roman alphabet would be as follows:Plain: abcdefghijklmnopqrstuvwxyz Cipher: ZYXWVUTSRQPONMLKJIHGFEDCBA
An easier, simpler and faster way of doing this is:
First 13 letters: A|B|C|D|E|F|G|H|I|J|K|L|M Last 13 Letters: Z|Y|X|W|V|U|T|S|R|Q|P|O|N
Atbash can also be used to mean the same thing in any other
alphabet as well. This is a very simplesubstitution cipher .For example, in Atbash, the letters "nlmvb" indicate the word "money".
A few English words 'Atbash' into other English words. For example, "hob"="sly", "hold"="slow", "holy"="slob", "horn"="slim", "zoo"="all", "irk"="rip", "low"="old", "glow"="told", and "grog"="tilt".
It is a very weak cipher because it only has one possible key, and it is a simple monoalphabetic substitution cipher. However, this may not have been an issue in the cipher's time.
The Atbash cipher is referenced in
Google 's Da Vinci Code Quest, in which participants must decode a common word from Atbash.The Atbash Cipher as an Affine cipher
The Atbash cipher can be seen as a special case of the
Affine cipher .If you define the first letter of the
alphabet to be 0, the second letter to be 1 and so on up to the last letter of the alphabet being the number of letters in the alphabet-1; then the Atbash cipher may be enciphered & deciphered using the encryption function for anAffine cipher :Where, for the Atbash cipher: in which m is the number of letters in the alphabet ( for monocase English).
This may be simplified to:
If, instead, the first letter of the alphabet is defined to be 1, the second letter to be 2 and so on, the encryption function for the Affine Cipher becomes:
Where, for the Atbash cipher: , in which m is the length of the alphabet.
This may be simplified to:
ee also
*
Gematria
*Hebrew language External links
* [http://home.cogeco.ca/~cipher/cyprogs.htm#atb MS-DOS software for encrypting and decrypting with Atbash]
* [http://www.murky.org/blg/2004/09/03/atbash/ Atbash] as discussed on [http://www.murky.org/blg/category/cryptography/ The Beginner's Guide to Cryptography]
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