Cryptography

Cryptography is the art of hiding data.

Today, it focuses on two important features:

• Encryption: The art of hiding data that can be later recovered if you only know how to do it. Usually, this is a method that involves an encryption algorithm and a secret key.
• Digital Signing: The art of providing a checksum that can uniquely identify data.

Cryptography for Dummies

Here's a short article that describes how encryption works: Encryption for Dummies