Ethical Hacking: Techniques, Tools, and Countermeasures, 4th Edition

Cryptographic History

Humans have used cryptographic techniques for thousands of years. The only things that have changed are the complexity and creativity of the techniques. Today cryptography covers the confidentiality, integrity, and nonrepudiation of information, but originally it was used only to protect confidentiality. A quick look at cryptography’s colorful history shows some of its diverse applications:

• Egyptian hieroglyphics—In many ways, the colorful and mysterious glyphs that cover the walls and tombs of ancient Egyptians can be considered a form of secret writing. This system is a great example of a substitution cipher.

• Scytale—The Spartans used this technique to send encoded messages to their military’s front lines. It relied ...