The incredible growth of the Internet has excited businesses and consumers alike with its promise of changing the way we live and work. But a major concern has been just how secure the Internet is, especially when you're sending sensitive information through it.

Let's face it, there's a whole lot of information that we don't want other people to see, such as:

  • Credit-card information
  • Social Security numbers
  • Private correspondence
  • Personal details
  • Sensitive company information
  • Bank-account information


E-commerce relies on the ability to send information securely.

Information security is provided on computers and over the Internet by a variety of methods. A simple but straightforward security method is to only keep sensitive information on removable storage media like floppy disks. But the most popular forms of security all rely on encryption, the process of encoding information in such a way that only the person (or computer) with the key can decode it.

In this edition of HowStuffWorks, you will learn about encryption and authentication. You will also learn about public-key and symmetric-key systems, as well as hash algorithms.