Because it mirrors a point I often feel compelled to make when discussing security and cloud computing, I wanted to highlight a couple of paragraphs from Cloud Computing: Assessing the Risks by Jared Carstensen, Bernard Golden and J.P. Morgenthal as excerpted in Tech Target.
It's important to understand that this risk limitation [whereby service providers shift the primary responsibility for risk to consumers] is not unique to Cloud Computing. Outsource providers (e.g. firms that take over operating a company's IT data centre) also limit their financial responsibility in the event of an outage. Therefore, it is important not to regard this risk limitation as a complete restriction on using a Cloud provider, unless, that is, a company regards any risk limitation by a service provider as unacceptable. In that case, the company should continue to operate its own computing environment and forego use of an external Cloud provider.
The important point from this discussion is that when Cloud Computing security is raised as an issue, other issues are often being addressed. It's important to distinguish what type of issue is of concern, as that will change the method of evaluating the issue, the demarcation of the trust boundary and the appropriate actions to be taken by the Cloud user.
One of the reasons why I think this point is important is that discussing overall IT governance discussions solely in terms of security (whether we're talking public clouds, private clouds, or--increasingly--some manner of hybrid IT) is far too narrow a framing. This narrow framing, in turn, often leads to thinking about the issue in narrow technical terms such as multi-tenant security features, encryption and key management, and physical facility protection.
These are important matters certainly. But they're also matters that public cloud providers (like other types of outsources) can reasonably argue they have well in-hand using well-established procedures and processes. The more difficult answers about where workloads should run come down to broader questions--and those answers may well change over time.
(I covered some of these broader issues in a presentation at the Red Hat Summit in June. I'm hoping to get a version of that presentation Beyond Safety: Controlling Clouds posted over the next month or so.)