chapter discusses the basics of symmetric encryption algorithms.
Message integrity checking and hash functions are covered in Chapter 6. The use of cryptography on a network is
discussed in Chapter 9.
Many of the recipes in this chapter are too low-level for
general-purpose use. We recommend that you first try to find what you
need in Chapter 9 before resorting to building
solutions yourself using the recipes in this chapter. If you do use
these recipes, please be careful, read all of our warnings, and do
consider using the higher-level constructs we suggest.