Chapter 6 - Cryptography

Abstract

The objective of cryptography is to hide information so that only the intended recipient can access it. This chapter focuses on cryptographic techniques and their application. The two main categories of cryptography are symmetric key and asymmetric key cryptography. Symmetric key cryptography uses a single secret key, while asymmetric key cryptography uses a pair of public and private keys. Each algorithm has its own relative speed, security, and ease of usage. Data Encryption Standard (DES) is the oldest and most widely known modern encryption method. Advanced Encryption Standard (AES) was designed, as a secure replacement for DES that can employ several different keysizes. Both of these techniques are symmetric key and are explained in the chapter. Where symmetric cryptography combines a single key with the message for a number of cycles, asymmetric cryptography relies on numbers that are large to be factored. Brute force attack is the single attack that will always succeed against symmetric cryptography and is used frequently to crack passwords. It closes with a discussion on identifying improper use of cryptography algorithm, and accessing amateur cryptography attempt.