HyTrust wants to help any IT manager who not only has to look after many virtual machines but also has to deal with looming compliance audits. The security company received $18.5 million in its third round of funding today.

HyTrust is built specifically for virtual machines: a number of different computers that all live inside one piece of hardware. Virtual machines help keep costs low on the data center front, but they’re a relatively new challenge in terms of security.

HyTrust calls itself a “virtual appliance” that is installed right on the hypervisor, or the piece of technology that makes it possible to virtually separate different computers on one server. From there HyTrust monitors all of the traffic on your systems and can even tell if your physical hardware has been tampered with through a partnership with Intel.

More specifically, companies use HyTrust to enforce “compliance policies.” If you’re a bank or a health care company, you must follow certain policies in order to ensure that your systems are secure. These organizations are subject to audits to make sure that they’re following those policies, given the sensitive information on their systems. IT managers input their policies into HyTrust, and the technology will make sure they’re being followed.

The funding comes from Intel Capital and Fortinet as well as existing investors Granite Ventures, Cisco Systems, Trident Capital, Epic Ventures, VMWare, and In-Q-Tel, the CIA’s funding arm. The Mountain View, Calif.-based company¬†last raised a $10.5 million round in 2010.

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