Cryptology is the science of coding and decoding secret messages. It is divided into cryptography, which concerns designing cryptosystems, and cryptanalysis, which is concerned with breaking cryptosystems. 

The word cryptology has its origin in ancient Greek and is made up of two components: kryptos, which means hidden, and logos which means word. Cryptology is believed to be as old as writing, and sign language could be considered the earliest form of cryptology. From the start of civilization to the advent of mass electronic communication, cryptology was mainlyused to safeguard military and diplomatic communications. Since then it has also become part of common manís communication as more and more people are turning to electronic communication like e-mail. For example, in the past, cryptology was used by the military during wartime to make sure that the strategies were not leaked to  opponents, but today we send encrypted e-mails to our buddies to make sure that they are not read by our parents.

Cryptography deals with developing cryptosystems, which can be used to covert the messages from unintended readers. But it is in the nature of human beings to keep trying to know the secrets of others. This gave rise to the fascinating science of cryptanalysis. Cryptanalysts  try to break cryptosystems by reading messages that are not intended for them. Since cryptography is used in a wide variety areas including simple e-mail, highly important and secretive military communication, and in e-commerce, there is a lot of gain for cryptanalysts if they break a cryptosystem. History has proven that cryptology is a never-ending struggle between cryptographers and cryptanalysts.

Cryptology is not just the science of secret communication but, as believed by many, is itself a secret science. As cryptography plays an important role in military communication, many cryptosystems that are more powerful them the ones in use today could be classified secret by the governments around the world. 

Cryptography is not only used to safeguard a message in transit but can also be used to safeguard information residing in a computer system. For example files and databases can be encrypted to make sure that they are not ready by some one who hacked into the system. Cryptography can also be used to authenticate and authorize users for a single system or a network.

In this website we present some of the cryptosystems, which have been and/or are being widely used. For every cryptosystem we have give a brief history, in depth explanation with example and Java Script/Java Applet Interactive demo. To use this website, you website should be java enabled and support flash. If your browser is not support flash then you wont be able to see the menu on the left hand side of the page.