Cloud computing security (sometimes referred to simply as "cloud security") is an evolving sub-domain of computer security, network security, and, more broadly, information security. It refers to a broad set of policies, technologies, and controls deployed to protect data, applications, and the associated infrastructure of cloud computing. Cloud security is not to be confused with security software offerings that are "cloud-based" (a.k.a. security-as-a-service).
Many commercial software vendors have offerings such as cloud-based anti-virus or vulnerability management.Third-party cloud computing represents the promise of outsourcing as applied to computation. Services, such as Microsoft’s Azure and Amazon’s EC2, allow users to instantiate virtual machines (VMs) on demand and thus purchase precisely the capacity they require when they require it. In turn, the use of virtualization allows third-party cloud providers to maximize the utilization of their sunk capital costs by multiplexing many customer VMs across a shared physical infrastructure.
In the emerging cloud security space, Craig Balding laid the foundation for cloudsecurity.org (http://cloudsecurity.org/) This site is for people that want to learn more about cloud computing from an enterprise security perspective. Lot of interesting topic, discussion, blog are available and so the interested folks can fetch the benefit out of it