Professional Visual Basic 2012 and .NET 4.5 Programming

Encryption Basics

Rather than present an exposition of cryptography, this section is meant to familiarize you with basic techniques required to deal with .NET security and protect your Web services through encryption. There are four different categories of cryptography: encoding, hashing, and symmetric and asymmetric encryption.

First you will review each of these four different cryptographic categories. The first is encoding, which, as you may already know, if you are at all familiar with encryption, doesn't actually protect information. The most common encodings are things like UTF8, UTF7, and Base64 encoding. These encodings are typically used to take information that might interact with a container and hide the special characters. Thus, if you want to embed binary data within an XML file and want to ensure that the binary data won't interfere with the XML, you can Base64 the data, and it can safely be placed within an XML file.

Encoding is quite common for passing hidden or state data in Web pages, MIME, and XML file formats. For example, in ASP.NET, ViewState is an encoded block of information about the state of an ASP.NET page. However, keep in mind that encoded data, while not immediately humanly readable, uses a public algorithm to create its string. Encoding algorithms are designed to be quickly and easily reversed, and without any form of implied privacy. This means that anyone can reverse the encoded data, so for ASP.NET, ViewState does not protect the data which has ...