This is short slides about federated identity and gatekeeper pattern. The source is from "Cloud design patterns" by Microsoft.

1. Presented by: Roger Chien
Mar 2014
Content is from “Cloud design patterns – perspective architecture
guidance for cloud applications”, by Microsoft.
Cloud Design Patterns
Federated Identity & Gatekeeper Pattern

2. Federated Identity Pattern
 Delegate authentication to external identity provider 
LDAP inAAA.
 Eliminates the need of multiple login credentials for every
service. (e.g. Open-ID)
 More easily for privilege management. (people leave and fine
grain control)
 Application and services can save the overhead of identity
management.

3. Federated Identity Pattern
Could be chain of trust
In STS.

4. Federated Identity Pattern - Issues
 Can be single point of failure.
 Need fine grain control for features & resources via Role
based access control (RBAC).
 Need to maintain user information for claim based
authentication (thru registration)
 If there is multiple STS, have to deal with sign-in redirection.

5. Federated Identity Pattern - Example
 User in large enterprise to use SaaS application onWindowsAzure.

6. Gatekeeper Pattern
 Using a dedicated host instance that acts as a broker between
clients and applications/services, validates and sanitizes
requests and passes requests and data between them.
 Add another layer of security and reduce attack surface.
 Fit for:
 Applications that handle sensitive information, expose services
that must have high a degree of protection from malicious
attacks, or perform mission-critical operations that must not be
disrupted.
 Distributed applications where it is necessary to perform
request validation separately from the main tasks, or to
centralize this validation to simplify maintenance and
administration.

7. Gatekeeper Pattern

8. Gatekeeper Pattern
 Controlled validation: validates all requests and rejects those
didn’t meet requirement.
 Limited risk and exposure: Gatekeeper itself is not access to
credentials and keys. If gatekeeper is compromised, those
information are not exposed.
 Appropriate security: Run gatekeeper in a limited privilege
mode.
 Gatekeeper is actually an application firewall.

9. Gatekeeper Pattern - Issues
 The trusted nodes only expose necessary interfaces to
Gatekeeper.
 Run in limited privilege mode (Gatekeeper and trusted
nodes are in separated hosted services orVM)
 Gatekeeper only do validation and sanitization, not touch any
processing related to services/applications.
 Secure channel (SSL/TLS/HTTPS) is required for
communication between Gatekeeper & trusted nodes.
 Performance impact.
 Could be single point of failure.

10. Gatekeeper Pattern - Example