The use of cryptography dates back to the beginning of man's use of written language. The word cryptography comes from the Greek meaning hidden writing. The oldest physical examples we have of using written codes dates back to the Spartan government's use of scytales. These were special devices in which the sender and recipient each had a special cylinder of the same size. A ribbon was wrapped around the cylinder and the message written vertically on the ribbon. The ribbon was worn as a belt and delivered to the receiver. Once the receiver wrapped the ribbon on the appropriate cylinder the message could be deciphered by reading vertically.

A few noted cryptographers were:

• Julius Caesar: He developed the first use of a substitution alphabet for ciphers.

• Roger Bacon: Quoted as saying "A man is crazy who writes a secret in any other way than one which will conceal it from the vulgar."

• Sir Francis Bacon: He developed the reputed baconian cipher using a bilateral system consisting of 5-bit binary encoding and utilizing a variation in type face as the key. There is ample evidence showing that Bacon was indeed the author of Shakespeare's work and these works are riddled with baconian ciphers.

• Thomas Jefferson: Invented a wheel cipher.

• Charles Babbage: Re-invented another wheel cipher.

• Edgar Allan Poe: He was very fond of and talented at creating and deciphering key word codes.

• Alan Turing: Very interested in cryptography and worked on government code-breaking.

Cryptography has become a very important part of computer technology and an integral part of the Internet. The ability to encrypt and decrypt information is crucial to secure financial transactions and even elementary forms of on-line privacy.

For our purposes here, we will concentrate on simple ciphers and cryptograms as an exercise in using both sides of the brain. Intuition plays a heavy role in the deciphering process. Whether it is recognizing a pattern in the coded message, or simply remote viewing the cipher key, those who are adept at code-breaking have always credited their art to insightful means. While the bulk of deciphering remains in the analytical realms, the reasoning of the algorithm used to encode the message, both kinds of thought are useful in breaking a code.

As an overview, here is some basic terminology used in the art of code-breaking. Cryptography is the science of keeping written messages secret. Cryptanalysis is the art of breaking the cipher, or retrieving the message without knowing the proper key. Cryptology is the branch of mathematics that studies the mathematical foundations of cyrptographic methods, i.e. the algorithms useful in creating codes, both public and private. A cipher is a method of encryption and decryption. All ciphers depend upon a key or algorithm to code the message and make it possible for the intended receiver to decode the message.

There are two types of key-based algorithms, symmetric (or secret-key) and asymmetric (or public-key). The difference is that the symmetric keys use the same algorithms for encryption and decryption. An asymmetric algorithm uses a different key for encoding and another for decoding. Asymmetric ciphers permit the encryption key to be public, allowing anyone to use the key for encoding. The encryption key is called the public key and the decryption key the private or secret key. Computers generate most modern cryptographic algorithms with specialized hardware and software devices.

Simple cryptograms use two main types of ciphers, a substitution cipher or a transposition cipher. A substitution cipher replaces individual letters (singly or in groups) with others within a definite system and a key. Of this type there are also monoalphabetic and polyalphabetic ciphers. A monoalphabetic always uses the same letter of the alphabet for the ciphertext letter. Below is a simple wheel showing the use of a monoalphabetic substitution

• Check for one-letter words. The word is A nine times out of ten. If A doesn't work, try I.
  
  
• A three-letter word may be THE especially if it begins the crypogram, both first and last letters are of high frequency, or the same three letter word appears more than once.
  
  

• Memorize the first six letters of the frequency alphabet, E, T, A, O, N, and I. The complete frequency alphabet is:
  E T A O N I S R H D L U F C M W P G Y B V K X J Q Z

• Try to identify vowels. One way is to examine how many different letters adjoin a high-frequency cipher letter. The four most used vowels, A, E, I, O must touch the 20 consonants more often than the consonants touch the different vowels. Also, every sequence of five or six letters most always contains a vowel.

• Look for doubled letters. The most often used doubles are L, E, S, O and T.

• Check the final letters of the cipher’s words. Letters that appear often as final letters include E, W, T, D, N, R, G, K, and Y.

With these helpful hints you are well on your way to solving most cryptograms that are published today. There is a myriad of encryption methods, and once you have the method or system you can fairly easily unlock the key. Intuition is the strongest factor in gaining insight to a key. Allow your subconscious to scan the ciphered text and quietly wait for some subtle feelings of how to proceed. Once you've discovered the key or some important words, logical thought takes over and you proceed to unravel the algorithm that was used to encrypt the message.

This is another fun way to use both sides of the brain. The Internet is full of sites that have cryptograms. As you play with this you may become interested in the science of cryptography itself. Enjoy the process and create some new neural pathways as a result.

We have a special applet created by Jos van Uden that will allow you to test your cryptographic skills. To use this applet click here.

For an in depth study of cryptology as well as a thorough examination of the controversy of Francis Bacon's authorship of Shakespeare's plays go to Penn Leary's site.