What is cloud computing?

Cloud computing is a term that isn’t precisely defined yet. Some define it as anything that takes place outside of the your firewall is “in the cloud.” Others define it as the next stage of utility computing. Whatever it is, it’s big now, and looks like it’s only going to get bigger. For our purposes, cloud computing is when data retention and processing are turned over to an outside service provider. As noted by howstuffworks.com, if you've used one of the popular web-based email clients such as yahoo, gmail, or hotmail, you've used cloud computing.

That seems pretty harmless. But protecting email is one thing. Protecting major financial, medical, or other sensitive data is quite another. And we have problems protecting the email. There are ways of analyzing memory usage to steal data when two programs are running on the same computer and operating system. Theoretically it should work for two virtual computers running on the same server, but with dozens or hundreds of them running on a server, it was believed that actually isolating useful data that way was very unlikely.

Technology Review ran a story on cloud security called "Security in the Ether". One of the first things it talked about was three researchers who had shown that it is possible to monitor virtual machines the same way. They did their research on Amazon's cloud servers, but Amazon says they have taken steps to make sure that data can't be stolen by that method anymore.

But that isn't the only concern about cloud computing. There are concerns over downtime, application security, data security, the human factor. Perhaps you've heard that the more people who know a secret, the less likely it is to remain secret? There's a cloud computing corollary. The more people in the cloud, the more likely there will be a breach. And cloud computing is only economical if lots of people are using it.