Dirt speak truth.

Hello, Welcome back. Many people believe that ciphers start from caesar cipher. Some are believe hieroglyphics are first. When archeologist had discovered that israel civilization use cipher, 1000 years before egyptian civilization. Israel civilization had introduced first cipher system named as atbash cipher system.
Atbash cipher belong to monoalphabetic substitution cipher category. It's simple, You can replace first letter with last one and so on.
                        A = Z ,B = Y ...   
 Do you solve decipher a text
              message : "Meet me at 9pm "
you can comment your  answer in comment section.

In holy book ingir(Bible) there are many verses proves atbash cipher system existence. Sheshach  is word used in Holy Book. According to wikipedia Sheshach is common example. However this verse where Sheshach found "The king of Sheshach shall drink after them". When cryptographer decrypt with the help of atbash cipher, it provide us mind blowing information and that is Babylon. Babylon was a kingdom of Mesopotamia (Iran and iraq ).

Mathematical formula Encrypted message and return back original state.
                              E(X) = D(E(X))
This cipher is a special case of affine cipher.
                    E(X) = ((m-1)x+(m-1))mode m
    More details about affine cipher will be share next time.
Thank you , Have a nice day