Rest - how to handle authentication in microservice architecture

Question

I am creating a series of RESfull services using the microservice architecture described by Martin Fowler on his blog ( http://martinfowler.com/articles/microservices.html ) But I need all the methods to be accessible exclusively to authorized users. I am implementing a service facade that should handle user authentication and redirect api requests to the appropriate service. How should the facade handler authenticate to the main services? Should all services use basic HTTP authentication on their own, or is there a way for the facade to inherit the user that it authenticates?

thanks