The public cloud delivers unbundled, distributed infrastructure — compute, storage, and network resources are here for the asking with nothing more than an API call. Platform services like databases are similarly available for developers wanting to consume resources above the infrastructure level. À la carte infrastructure, available self-service to developers, allows for agility and elasticity previously unavailable to enterprise IT.

But as the sheet metal surrounding this infrastructure falls away, so does the physical perimeter of the enterprise data center, leaving distributed infrastructure with no clear boundary. The perimeter has proved a convenient, if not always optimal, spot to insert data center security functions. With it gone, where should security functions reside?

In some cases, the answer is easy. Network segmentation previously provided by physical network subnets has been abstracted in AWS as a virtual private cloud, or VPC. With a simple API call, VPCs are available cheaply and easily.

Other instances aren’t so simple. The AWS object storage service, S3, is one example. The AWS Elastic Block Store volumes, or EBS, are another. AWS allows volumes and S3 objects to be shared between accounts in creative and useful ways, far beyond what their physical analogs could achieve. However, as I've written before, developers frequently misconfigure permissions, making their data vulnerable to loss. As cloud service providers expand the flexibility of their services, complexity and the risk of misconfiguration grow. 

Distributed infrastructure demands distributed security, and the industry is responding. VMware NSX and AWS security groups offer good solutions for network segmentation and firewalling in a homogenous cloud.

While these solutions suffice in single environments, these solutions don't work in hybrid environments, and they become unwieldy at scale. In hybrid environments, routers, firewalls, and the rest function under different controls and different conditions. They don't scale because any policies created — any single configuration — cannot apply across environments.

The rise of distributed infrastructure didn't result only from the rise of cloud, but it is largely attributable to it. With past data centers, the switch or router that forwarded data to the Internet relied on physical boxes (firewalls, load balancers, IDP, etc.) for security services. In today's cloud, virtualized software infrastructure inserts this functionality into every server. Rather than trying to replicate perimeters on infrastructure we don't control, the most logical approach implies securing applications individually — creating a perimeter for every application. The old perimeter has vaporized, but it needs to reappear in this distributed world.

For the new perimeter, the best solution is properly implemented encryption. Encryption allows IT teams to maintain control over assets in environments they don't physically control, especially as those assets become increasingly distributed. Encryption allows IT security to ensure the confidentiality and integrity of enterprise resources in any environment — particularly across the hybrid cloud.

In other words, encryption enables logical control over assets even in the absence of physical control. This logical boundary around enterprise assets is the new perimeter. The enterprise holds the keys, and their assets remain under their control.

With distributed infrastructure as the new normal, the security space is racing to catch up. But to accommodate complexity and scale, we need to adopt a model that attaches "distributed security" to workloads and data rather than replicating traditional data center solutions.

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