TheCodeBreakers
from the Romans — and from the greatest Roman of them all. Julius
Caesar thus impressed his name permanently into cryptology.
Suetonius, the gossip columnist of ancient Rome, says that Caesar
wrote to Cicero and other friends in a cipher in which the plaintext
letters were replaced by letters standing three places further down the
alphabet, D for a, E for b, etc. Thus, the message Omnia Gallia est divisa
in partes tres would be enciphered (using the modern 26-letter alphabet)
to RPQLD JDOOLD HVW GLYLVD LQ SDUWHV WUHV. To this day, any
cipher alphabet that consists of the standard sequence, like Caesar's:
Plain a b c d e f g h I j k l m
Cipher D E F G H I J K L M N O P
Plain n o p q r s t u v w x y z
Cipher Q R S T U V W X Y Z A B O
is called a Caesar alphabet, even if it begins with a letter other than D.
It must be that as soon as a culture has reached a certain level,
probably measured largely by its literacy, cryptography appears
annaabi.ee 
