With Google launching its new cloud-based enterprise apps marketplace these days, many people are paying closer attention to a maturing overall cloud offering. One of its components which caught my attention today is ironically something that you are meant to install enterprise-side: the Secure Data Connector (SDC).

The SDC lets the enterprise control access to its private resources (resources behind the enterprise’s firewall) from google apps. This illustrates an increasingly popular pattern relating to enterprise cloud adoption where applications deployed on the cloud need to access private resources located securely behind the enterprise’s firewalls. This pattern is also referred to as the ‘distributed SOA’, the idea that an enterprise’s SOA spans across multiple service zones both on and off-premise.

Google’s SDC is essentially reverse-proxy software, which you install on a server deployed in your DMZ. SDC maintains a secure link with Google apps and enforces basic rules relating to access control. Although some aspects of the solution borrow concepts from standards such as OAuth, the solution as a whole is mostly proprietary.

There is no doubt that this pattern is very important to address for any enterprise leveraging cloud-side applications. However, before deploying Google’s own gateway, and the ones of each cloud provider that you will eventually rely on, consider a best-of-breed specialized piece of infrastructure (SOA gateway) that works across cloud providers using standards and meets the highest threat protection requirements.

As it is, google apps access private resources through such an SOA gateway just as well as they will through the proprietary SDC. This type of openness is crucial in your choice of cloud provider. Proprietary security mechanisms increase vendor lock-in – perhaps one of the most important barrier to adoption for rich enterprise cloud use. Investing in security solutions that only works with one cloud platform affects your long term ability to switch provider.