For most of its modern history, cryptography has been shrouded in secrecy. Political and military organizations have been using cryptography to communicate sensitive information securely. They employ the most brilliant mathematicians and information theorists in the hopes that they will create unbreakable codes. At the same time, these cryptologists are put to the task of breaking the codes created by the enemy抯 brilliant theorists. The successes and failures of cryptologists have been known to profoundly influence the outcome of wars.
For most of the history of cryptography, advanced techniques for creating secret codes and ciphered transmissions were the exclusive domain of government organizations. Code makers and code breakers were kept far away from the public and
academic spotlights. Any unauthorized research into cryptography was strongly discouraged. The existing literature on cryptography went little further than the theoryneeded to solve the cryptogram puzzles in a newspaper. Truly effective cryptography techniques require an advanced understanding of mathematics, and the few people with these skills were often hired by government agencies. As a result, the general public knew very little about cryptography.
This all changed in the mid-1970s as computers became a viable tool for academic research. A number of mathematicians started exploring cryptography and
realized that it would be a powerful tool for protecting the communications of individuals. Over the next few years, the public抯 understanding of cryptography would dramatically advance. By the end of the �s, cryptography would become a viable tool for securing personal and business communications.
The most straightforward use of cryptography is for secure communication. Encrypted messages are sent between two parties to ensure that the message, if intercepted by a third party, cannot be read. Thanks to the development of public key systems, secure communication has now become commonplace.
Identification and authentication is another area where cryptography is commonly used. An example of encrypted authentication and identification is observed when withdrawing money from a bank. The automatic teller machine obtains the data on your bankcard and your secret pin code. Cryptography protects this information when it is sent to your bank for verification.
The above information is the start of a chapter in "Network Security Illustrated," published by McGraw-Hill and available from amazon.com, as well as your local bookstore. The book goes into much greater depth on this topic. To learn more about the book and what it covers, click here.
Below, you'll find links to online resources that supplement this portion of the book.