Читать книгу Information Security - Mark Stamp - Страница 19

Cryptography is a fundamental tool in information security. Cryptography has many uses, including providing confidentiality and integrity, among other vital information security functions. We'll discuss cryptography in detail, as a working knowledge of crypto basics is essential background for any informed discussion of information security.

We'll begin our coverage of cryptography with a look at a handful of classic cipher systems. In addition to their obvious historical and entertainment value, these classic ciphers illustrate the fundamental principles that are employed in modern digital cipher systems, but in a more user‐friendly format.

With this background, we'll be prepared to study modern cryptography. Symmetric key cryptography and public key cryptography are the two major branches of cryptography, and each plays a prominent role in information security. We'll spend an entire chapter on symmetric ciphers, and another chapter on public key systems. We then turn our attention to cryptographic hash functions, which are another fundamental security tool. Hash functions are used in many different contexts, some of which are surprising, or even bordering on the counterintuitive (e.g., blockchain).

Then we'll briefly consider a few special topics that are related to cryptography. For example, we'll discuss steganography, where the goal is, essentially, to hide information in plain sight.