Using Encryption

Abstract

Why would we want to use encryption? The answer is surely obvious: while some of the information stored on a computer may be public, there is also plenty that is not and should not be public: passwords and other access information, personal information of various sorts, sensitive company data, and so forth. Such information needs to be available; that is why it’s on the computer in the first place. But that information needs to be hidden somehow, made inaccessible to any third party who, by chance or malicious design, happens to stumble onto it. In this chapter, we’ll be discussing how and why to hide information, whether on disk or in a database. We will look at how to accomplish both symmetric and asymmetric encryption using PHP and the most common algorithms.