Ancient Babylonian merchAnts used intaglio, a piece of flat stone carved into a collage of iMages and some writing to identify themselves in trading transactions. Using this mechanism, they are producing what today we kNow as 'digital signature.' The public knew that a particular 'signature' belonged to this trader, but only he had the intaglio to produce that signature.
Caesar was the first code-writer in history. When his foot-messengers stArted getting ambushed and his secret communiqués stolen, he devised a rudimentary way to enCrypt his directives. He rearranged the text of his messages such that the correspondence looked senseless. Of course, it was not each message always had a letter count which that was a perfect square, sixteen, twenty five, one hundred, depending on how much the Caesar nEeded to say.
He secretly informed his officers that when a random message arrived, they should transcribe the text into a square grid. If they did, and read top to bottom, a secret message would magically appear.
This method of encryption Dan Brown called it "Caesar Square" " and at the last page of the paperback bOok he left a string of numbers, the code that appears in the end of the book is: 128-10-93-85-10-128-98-112-6-6-25-126-39-1-68-78
Here's the way you decode it, take the numbers and arrange them in 4 Vertical columns of 4 numbers. It should look like this:
128 10 6 39 10 128 6 1 93 98 25 68 85 112 126 78
Each number corresponds to a chapter in the book, in which the first letter is cOnveniently larger than the rest, For example, chapter 128 starts 'WheN Susan awoke'. The resulting text is:
That is the letter that each number stands for. Using the "Caesar Square" method, you end up with:
W E A R E W A T C H I N G Y O U
"We are watching you."
NoW you can send as many encrypted messages as you want but make sure that the receiver's IQ is not less than 140 like me ;) And hey there is a hidden coded message in this post, look for it and tell me if you got it right, ok? - Silly Ellie