Cryptography

Human ingenuity cannot concoct a cypher which human ingenuity cannot resolve. -- Edgar Allen Poe
The quest for a reliable means of keeping information completely secure is a troubling enigma that reaches far back into the history of mankind. From the concealment of top-secret military files, to the protection of private notes between friends, various entities over the years have found themselves in need of disguises for their transmissions for many different reasons. This practice of disguising or scrambling messages is called encryption, and in these days of ever-improving network technology, its importance is becoming more and more apparent.
The first encrypted messages were developed in ancient Egypt as series of disordered hieroglyphics. This means of encryption was very simple, utilizing a method called simple substitution. The original message, or plaintext, was encoded using a substitution cipher (a cipher is a method of encryption). Each letter (or picture, in this case) of the plaintext was simply replaced by another letter of the alphabet, resulting in the encoded message, or ciphertext. For example, the message,

"Welcome to Hartford."

could be encrypted as,

"Xfmdpnf up Ibsugpse."

In this example, each letter of the plaintext was simply replaced with the next letter in the alphabet. Actually, this example is a special form of substitution cipher known as a Caesar Cipher
Over time, previous ciphers were improved upon, and new ways to encrypt messages were invented. For example, people began to set pre-defined word lengths, so as to hide the lengths of words, making it harder to crack substitution codes. With the implementation of this improvement, the above message could look as follows:

"xfmdp nfupi bsugp se."

Recently, the invention of new mathematical techniques has accelerated this process to even better methods of encryption. In fact, cryptography has become so advanced that many of today's ciphers are considered to be unbreakable. 'Unbreakable,' however, is a relative term. Although it might take as long as several decades for one of today's computers to systematically decode ciphertext produced by some of today's leading methods of encrypting, who is to say what tomorrow's computers will be able to do? The fact remains that, in order for the ciphertext to be at all useful to the intended receiver, it must have some form of order to it, no matter how obscure this sense of order may be. Herein lies the problem. If there is an order to the cipher, regardless of how remote, there will always be the possibility that someone will find a way to exploit this order, and eventually crack the cipher.
Thus, the discovery of an absolutely secure means of communication continues to elude cryptologists today. We have certainly come a long way towards finding the perfect cipher, and yet, it would seem that our goal is still many miles ahead of us, if it even exists at all. And so, the quest persists...

There are several different types of encryption currently in use, of which we have selected some of the most famous to focus on. The following links will take you to their respective sub-pages which explain each type of encryption in greater detail, looking at the history, technique, and possible futures of each.

Main Page
Caesar Cipher
Simple Substitution Cipher
Vigenere Cipher
Gronsfeld Cipher
The German Enigma Machine
RSA Public Key Encryption
PGP -- Pretty Good Protection

Cryptogram of the Week

See if you can crack an encrypted message! Visit The Cryptogram of the Week!

CryptoTool

CryptoTool is a Macintosh program written by Professors Morelli and Walde to help you create your own ciphertext and crack that of others.

Who wrote the Shakespearean plays?

Click here to visit a new Web site that examines the hypothesis that Francis Bacon was the true Shakespeare. Of especial interest for us here in the home of Mark Twain are Twain's views on the question . The link is to a little known "autobiography" by Samuel Clemens in which he examines the Shakespeare-Bacon question. Highly interesting and entertaining!
This page has been brought to you by the following people:

Research: Brian Hart '99
Programming and Design: Chris Savarese '99
Supervision and Guidance: Professors Ralph Morelli and Ralph Walde
Special Thanks to Bryan Horling for the use of his cgi programs.
Trinity College of Hartford, CT

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Last Updated April 4, 1996