Tool
Atbash Cipher
The oldest mirror cipher: first letter for last, second for second last. Some scholars think it hides a name in the book of Jeremiah.
What the Atbash cipher is
Atbash swaps each letter of an alphabet for its mirror image: the first becomes the last, the second becomes the second last, and so on. In the Latin alphabet A becomes Z and B becomes Y. In Hebrew, aleph becomes tav and bet becomes shin. The name comes from those four Hebrew letters: aleph, tav, bet, shin.
It is one of the oldest ciphers we know of, and some scholars read a few words in the Hebrew Bible as Atbash substitutions for other names. Whether that was deliberate is argued over, and the book on hidden codes in this series (Written in the Open) sorts the certain cases from the disputed ones.
How to break it
There is no key, so there is nothing to guess. If you suspect Atbash, run the text through the decoder once. Because the mirror is symmetrical, decoding and encoding are the same operation.
Goes with
Written in the Open
Real codes, ciphers and hidden messages in old texts, art, music and buildings: the certain ones, the disputed ones, the hoaxes, and how to tell them apart.
About the book