Cloud Computing: Eyes on the Skies gives a good definition of Cloud computing. “Cloud computing is similar to what the tech industry has been calling "on-demand" or "utility" computing, terms used to describe the ability to tap into computing power on the Web with the same ease as plugging into an electric outlet in your home. But cloud computing is also different from the older concepts in a number of ways. One is scale. Google, Yahoo! (YHOO), Microsoft (MSFT), and Amazon.com (AMZN) have vast data centers full of tens of thousands of server computers, offering computing power of a magnitude never before available. Cloud computing is also more flexible. Clouds can be used not only to perform specific computing tasks, but also to handle wide swaths of the technologies companies need to run their operations. Then there's efficiency: The servers are hooked to each other so they operate like a single large machine, so computing tasks large and small can be performed more quickly and cheaply than ever before. A key aspect of the new cloud data centers is the concept of "multitenancy." Computing tasks being done for different individuals or companies are all handled on the same set of computers. As a result, more of the available computing power is being used at any given time.”
Clouds are on the horizon. I know very few data centers that host everything internally. Most, including my own, deliver a mixture of desktop applications, client-server applications, and hosted (e.g., cloud) web apps. The shift has an immediate impact on security planning. Information security architectures began with terminal-server applications and focused on strong perimeters. With apps moving to the desktops, the perimeter became a little wider and a little more porous. But we could still control the information, by restricting what data was on the desktops and using technologies like end-point security. In fact, one might argue that many of our controls today are based around restricting information to the data center and keeping it off the desktops. The next major shift, which we are already starting to see, is moving the information from data centers to third-party hosting providers. This is only going to accelerate as young people, weaned on MySpace and Gmail, join the workforce. Another accelerant which we may see in the next few years is another economic downturn. Both sociological and economical changes are moving the data from controlled perimeters to uncontrolled open spaces. The clouds on the horizon are coming nearer.
The open question is this: how do we build controls in an age of perimeter-less security?