The purpose of this section is to introduce the fundamental ideas and basic terminology used in modern cryptography. It is by no means a comprehensive reference on cryptography. If you want to learn everything a programmer needs to know about the subject, we recommend the excellent book Applied Cryptography - Protocols, Algorithms and Source Code in C, Second Edition, by Bruce Schneier.

Chapter 1. Basic Terminology
Learn basic terms used in cryptography.

Chapter 2. Symmetric Cryptography
Learn about several modern symmetric cryptographic algorithms and how they are different from each other.

Chapter 3. One-way Hash Functions
Learn about hash functions and how they are used in cryptography.

Chapter 4. Public-Key Cryptography
Learn about public/private keys and the important role they play in modern cryptographic systems.

Chapter 5. Digital Certificates
Learn about digital certificates and how they are used in secure communications.

Chapter 6. Secure Mail and S/MIME
Learn about Secure MIME (S/MIME) - the leading secure mail format.

Suggested Reading:

1. Schneier, Bruce. Applied Cryptography, 2nd, New York: John Wiley & Sons, 1996.