The whitepaper discusses how to secure microservices that are to be accessed by clients who communicate through the public internet. It also talks about a security architecture for microservices that addresses the risks and incorporates the countermeasures described in the other document, Microservices Security Principles. The security architecture described in this document is intended as a guideline. While the architecture can be used successfully in most situations as presented, it should not be used without first reviewing its suitability for a specific situation. Before beginning to make architectural decisions about security, it is crucial to have a clear understanding of the security risks that need to be protected against. It is also important to understand what the legitimate activities are that need to be supported so that trade-offs between security and convenience can be well understood.