What should we implement to authorize clients to use our web service?

Question

We have a web service that we will be hosting on a public web server and it will be contacted by web services hosted on web servers within the walls of a hospital. We have writ

Answer 1

Client certificates can be used to provide credentials from a caller to your webservices; it's not that hard to take the passed cert and do any additional evaluation to dictate what that cert has visibility into.