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, the chapter defines the important primitives, give security models and attack scenarios, discuss constructions that are popular in practice, and describe current research activity in the area. Security is defined in terms of the goals and resources of the attacker.
