Atbash is an ancient encryption system created in the Middle East. It was originally used in the Hebrew language; some historians and cryptographers believe there are such examples in the Bible. The name "Atbash" comes from the first Hebrew letter Aleph and the last Taff. The Atbash cipher is a simple substitution cipher that relies on transposing all the letters in the alphabet such that the resulting alphabet is backwards. Atbash is also a substitution cipher. Since each letter corresponds to another, it offers very little security. The first letter is replaced with the last letter, the second with the second-last, and so on. The completed cypher looks like so:
Plain: ABCDEFGHIJKLMNOPQRSTUVWXYZ Cipher: ZYXWVUTSRQPONMLKJIHGFEDCBA
An example plaintext to ciphertext using Atbash:
Plain: MEETMEATONE Cipher: NVVGNVZGLMV
As one can see, and as mentioned previously, the Atbash cipher offers no security once the cipher method is found.