7.1. An Overview of Cryptography

Cryptography is a field almost as old as humankind. The first recorded cryptographic efforts occurred 4,000 years ago. These early efforts included translating messages from one language into another or substituting characters.


You won't be tested on the history of cryptography in the Security+ exam; this information is included primarily for background purposes.

The following sections briefly discuss three categories of cryptography—physical, mathematical, and quantum—as well as code breaking. Quantum cryptography is extremely classified and is relatively new. The other methods discussed are well known and commonly used.

7.1.1. Understanding Physical Cryptography

Physical cryptography includes several ...

Get CompTIA Security+™ Deluxe: Study Guide now with O’Reilly online learning.

O’Reilly members experience live online training, plus books, videos, and digital content from 200+ publishers.