Mogull commented yesterday on my post regarding TCG's IF-MAP and remarked that in discussing cloud security and security models, the majority of folks, myself included, were focusing on the network:
Chris’s posting, and most of the ones I’ve seen, are heavily focused on network security concepts as they relate to the cloud. But if we look at cloud computing at the macro level, there are additional layers which are just as critical (in no particular order):

- Network: The usual network security controls.
- Service: Security around the exposed APIs and services.
- User: Authentication- which in the cloud world, needs to move to more adaptive authentication, rather than our current static username/password model.
- Transaction: Security controls around individual transactions- via transaction authentication, adaptive authorization, and other approaches.
- Data: Information-centric security controls for cloud based data. How’s that for buzzword bingo? Okay, this actually includes security controls for the back-end data, distributed data, and any content exchanged with the user.
I'd say that's a reasonable assertion and a valid set of additional "layers." There also not especially unique and as such, I think Rich is himself a little disoriented by the fog of the cloud because as you'll read, the same could be said of any networked technology.
The reason we start with the network and usually find ourselves back where we started in this discussion is because the other stuff Rich mentions is just too damned hard, costs too much, is difficult to sell, isn't standardized, is generally platform dependent and is really intrusive. See this post (Security Will Not End Up In the Network) as an example.
Need proof of how good ideas like this get mangled? How about Web 2.0 or SOA which is for lack of a better description, exactly what RIch described in his model above; loosely coupled functional components of a modular architecture.
We haven't even gotten close to having this solved internally on our firewalled enterprise LANs so it's somewhat apparent why it might appear to be missing in conversations regarding "the cloud." It shouldn't be, but it is.
It should be noted, however that there is a ton of work, solutions and initiatives that exist and continue to be worked on these topics, it's just not a priority as is evidenced by how people exercise their wallets.
And finally:
Down the road we’ll dig into these in more detail, but any time we start distributing services and functionality over an open public network with no inherent security controls, we need to focus on the design issues and reduce design flaws as early as possible. We can’t just look at this as a network problem- our authentication, authorization, information, and service (layer 7) controls are likely even more important.
I believe we call this thing of which he speaks, "the Internet." I think we're about 20 years late. ;)
/Hoff