To add to the previous post
Examples of anti virus software include McAffee, Norton, and AVG. These are programs that the public can purchase to protect their computers from malware, viruses, logic bombs, or phishing.
The same programs listed above provide the service of firewalling your entrance to the net. Once you are firewalled, you are assumed to be protected from people accessing information.
Anti spy software is the same as spyware killers, and they are included as part of the service from providers such as Norton et al, however, if you enter online territory which is very unethical you may want to purchase additional protection. Any website which does gambling, pornography, even games may have spyware attached to it as long as the site invites u to take a membership. That is how they get your information. Spybot, Spyware killer and others are for sale at Best Buy
The final one, encryption, is like the previous post said the process of taking information and coding it. That is done by your computer when you send e-mails, enter private info, passwords, et al.