Chris Swan, who is the security CTO for UBS bank, says that businesses will “clearly not” be able to use the public clouds for everything their enterprises need.

At the 451 Group’s Hosting and Cloud Transformation Summit, Swan argued that “there is a level of assurance that I don’t think the public cloud can at the moment provide”, a sentiment echoed by VMware president Tod Nielsen, who stated that while some enterprise workloads will end up in the public cloud, the bulk of such workloads will remain private.

There are a number of concerns that come with moving data to a public cloud, the most important of which being how much a company wants to risk its data being truly “public”. While the security of public clouds is improving, they are still seen to be not at the same level as VPS options or private clouds, and many IT departments fear that what they put on the public cloud will become public knowledge.

If a company has a public-facing Web site or data that they share publicly on a regular basis, then a move of that data to a public cloud makes sense. The next, more private layer of data requires more serious thought.

Currently, data breaches in public clouds are centered around applications, and according to Swan, it is there that dollars need to be spent. Once application security issues are addressed, he predicts that multiple, industry specific clouds will develop hybrid models that will provide companies with both security and functionality.

While the public cloud offers a broader access to many companies in terms of data availability, moving all information, applications and mission-critical data to the public cloud is something that most businesses will not do.