--Originally published at Mental Droppings of a Tired Student
Chances are, you’ve had the need for a secure secret form of communication at least once in your life. Let’s say you’re planning on cheating on an exam with the help of a friend, and have the need to deliver a message without disclosing that message to prying eyes… how to achieve total security that this message won’t be intercepted by say the teacher? And if it is intercepted make it seem as innocent and unrelated to the actual topic the message itself is about?
Let’s get some ideas on how to be sneaky and how being a sneaky bastard makes you big bucks in the fair kingdom of technology.
Cryptography is the art of protecting information by transforming it into an unreadable format, called cipher text. Only those who possess a secret key or the correct instructions can decipher the message. All of our information is encrypted and the method used to encrypted give the information more or less security.
The earliest form of cryptography was the simple writing of a message, as most people could not read. In fact, the very word cryptography comes from the Greek words kryptos and graphein, which mean hidden and writing, respectively . Let’s look at some cool old forms of cryptography shall we?
The oldest trick in the book, so to speak, is called the Caesar Shift Cipher. It consists of wrapping a tape around a stick, and then writing the message on the wound tape. When the tape was unwound, the writing would be meaningless. The receiver of the message would of course have a stick of the same diameter and use it to decipher the message. It utilized the idea of shifting letters by an agreed upon number (three
The Caesar Shift Cipher is an example of a Monoalphabetic Cipher. It is easy to see why this method of encryption is simple to break. If you’re not completely illiterate and have some common sense, you’re pretty much good to go. All a person has to do is to go down the alphabet, juxtapositioning the start of the alphabet to each succeeding letter. At each iteration, the message is decrypted to see if it makes sense. When it does appear as a readable message, the code has been broken.
Throughout history, entrusting a messenger with a private communication has been rife with problems. In da Vinci’s time, a major concern was that the messenger might be paid more to sell the information to adversaries than to deliver it as promised.
To address that problem, da Vinci invented one of the first rudimentary forms of public-key encryption centuries ago: a portable container to safeguard documents called a Cryptex. Da Vinci’s cryptography invention is a tube with lettered dials. The dials have to be rotated to a proper sequence, spelling out the password, for the cylinder to slide apart. Once a message was “encrypted” inside the container only an individual with the correct password could open it.
This encryption method was physically unhackable: If anyone tried to force the container open, the information inside would self-destruct. Da Vinci rigged this by writing his message on a papyrus scroll, and rolling it around a delicate glass vial filled with vinegar. If someone attempted to force the container open, the vial would break, and the vinegar would dissolve the papyrus almost instantly.
Today governments use sophisticated methods of coding and decoding messages. One hugely important application for encryption is bank activity, secure exchange of information. The following video explains how some banks deal with this:
In essence, the encryption he is talking about is impemented by developing software that performs these mathematical processing of information. I now hereby command you to continue reading about software encryption in my friend’s blog:
References:
http://www.inquiriesjournal.com/articles/41/a-brief-history-of-cryptography
http://archive.wired.com/culture/lifestyle/news/2003/04/58378?currentPage=all
