ABSTRACT
Cryptography is the science of data security. This chapter gives a brief survey of cryptographic practice and research. The chapter is organized along the lines of the principal categories of cryptographic primitives: unkeyed, symmetric key, and asymmetric key. For each of these categories, this chapter defines the important primitives, gives security models and attacks scenarios, discusses constructions that are popular in practice, and describes current research activity in the area. Security is defined in terms of the goals and resources of the attacker.
