- Implement federated identity. Since digital identity is extremely context-specific, SOA's highly distributed approach creates challenges in provisioning and access management. No one system tells you everything about a particular identity; rather, one service makes an assertion about an identity, and the relying services evaluate them.
In this light, it's critical to understand both the capabilities and limitations of your enterprise's current provisioning, access management and federation systems.
Fortunately, federated identity uses the basic principles of SOA to deliver identity as a service, extending the governance reach of the enterprise's identity management systems.
Your challenge is to enable federated identity use cases between service requesters and providers by creating a schema for representing the identity and the services that exchange identity assertions and results for authentication, authorization and auditing. The business benefits from increased integration with customers and partners.
- Bulletproof service registries. Service registries, which store and manage service interface information and associated policies, have at least two important security considerations. They contain valuable information, such as data schemas, service interface and security policy information that must be protected by access control.
Ideally, they should have the highest level of protection, like an OS kernel. Additionally, since the service registry is where the security policy and mechanisms' metadata is described at design time, and executed at runtime, the IT security team should look to it as a key enabling technology to publish and enforce security policy.
- Secure the middleware. Historically, middleware applications were considered to be "inside" the firewall, isolated from the outside world. SOA integration requirements place much greater reliance on middleware, such as enterprise service buses that enable reliable, asynchronous messaging and orchestration engines that manage interactions across multiple services. They function as decentralized hubs, aggregating enterprise services and data, and connecting key systems. This new role dramatically alters their security requirements and requires a review of your security architecture.
The key point is ensuring that messages have sufficient security rights to be routed in the network, while limiting access to the data itself. Think of an envelope holding a letter (the XML message) that requires the correct addressing and postage, but prevents the postal clerk (middleware) from reading its contents.
Gunnar Peterson is a managing principal at Arctec Group, which provides IT architectural services. Send your comments on this article to firstname.lastname@example.org.