The first recorded use of a cipher in communications in the Western World is that of one used by Gaius Julius Caesar to communicate with his generals. According to Suetonius, Caesar used a simple substitution code by changing the letters of the alphabet. In one code he just substituted the fourth letter down from the letter he wished to; thus D was substituted for A, and so forth. This code is easily broken by a knowledgeable cryptologist but may have been made more difficult in Caesar's day since letters were written without any space between words as is now done. In fact, Caesar was admired for his ability to look at a manuscript and quickly make out the specific words in what would have been a continuous line of letters. Another Roman historian believes that Caesar used several more sophisticated codes. In any event, the use of ciphers has a long history in the Western World.
|Note how this inscription from the Colosseum has no spacing.|
I wish I had followed your example, and wrote it in Latin, and that I had called my dear campana in die instead of αδνιλεβ. We must fall on some scheme of communicating our thoughts to each other, which shall be totally unintelligible to every one but to ourselves. I will send you some of these days Shelton’s Tachygraphical Alphabet, and directions.
|Jefferson's "wheel cypher."|