SaaS most commonly uses client-side key management. With this type of implementation, the software for doing key management is supplied by the cloud provider, but is hosted and run by the cloud customer. This allows for full integration with the SaaS implementation, but also provides full control to the cloud customer.
Although the cloud provider may offer software for performing key management to the cloud customers, with the Infrastructure, Platform, and Desktop as a Service categories, the customers would largely be responsible for their own options and implementations and would not be bound by the offerings from the cloud provider.

The most common and efficient manner of securing operating systems is through the use of baselines. A baseline is a standardized and understood set of base configurations and settings.
When a new system is built or a new virtual machine is established, baselines will be applied to a new image to ensure the base configuration meets organizational policy and regulatory requirements.