Amazing History of Secret Codes & Cryptography – Full Documentary
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Secret codes have been used for centuries. The first known cipher in history was developed by the Roman leader Julius Caesar. His code was very simple. In fact, you could probably crack it, if you took a bit of time. He just replaced one letter of the alphabet with another and it never changed. However, his enemies didn't catch on very quickly. A code was still a new idea! As people became smarter about the idea of codes, harder ciphers were developed. An Italian, named Leon Battista Alberti, made a new invention, called a cipher wheel. This had two circles, both engraved with alphabet letters. When you matched each wheel in a certain way, a code could be both created and cracked. However, if the enemy didn't know where to match the wheel, you could hide some pretty good secrets, even if they had a similar wheel!
As time progressed, codes and ciphers have gotten more and more sophisticated. Technology began to be used to make more complicated codes. They have even been used for everyday people, who weren't spies. When the telegram was used to send messages, they charged by the word. You could write up to ten letters in a word for the same price. To cut costs, people made up codes. A group of letters meant a certain phrase. If you stop and think about it, we still use codes in this way today. Just think about the last text message you sent!
Different Types of Codes and Ciphers
There are many different types of codes and ciphers. A code is a system where a symbol, picture or group of letters represents a specific alphabetical letter or word. A cipher is where a message is made by substituting one symbol for a letter.
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Some common codes that have been used by spies:
American Sign Language
Morse Code
Navajo and other unwritten ancient languages
Picture codes
Common ciphers:
Alphabet ciphers
Math based ciphers
Transposing or substituting letters
Codes and Cipher Systems
The Ceasar Cipher - This cipher (aka. shift cipher) is a substitution cipher, where letters are replaced by a letter with a fixed shift in the alphabet.
Pigpen Cipher - The pigpen cipher (aka. masonic cipher) is a very simple substitution cipher, that goes back all the way to the 18th century.
Vigenere Cipher - The Vigenère cipher (which is actually French and sounds a bit like visionair) is a very old way of coding that's designed to mask character frequency (checking character frequency in a piece of coded text is one of the most well-known ways of breaking code).
Book Cipher - Book ciphers are a kind of secret code, that uses a very common article (a book) as the key. All they have to do is to transmit the location codes that are needed to pinpoint specific words in that book.
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