title: How to implement simple WCF security
body: <p>We have a C# client app that communicates to our C# backend service via WCF. We want to make sure that each WCF call made to our service is from a user that has logged into our client and not via some hacker who has figured out how to call our WCF services. </p>
  
  <p>I suppose there are several ways we could ensure this. One of which is to have our backend Login method return some sort of token that each client WCF call must then pass as part of the WCF call. In order to get such a token, the caller would have to provide valid login credentials. For each WCF call then, the token would get validated on the backside. If the token cannot be validated, the WCF call fails.</p>
  
  <p>I'd like a simple straightforward way of doing this. We don't need anything super complex and secure. Anyone have any information on the standard way of accomplishing this? We're using .NET 4. I should add that I don't have a great deal of experience with WCF.</p>
  
  <p>A little more information. We have two different client apps calling our WCF services. One is a WPF based client and the other is a browser based app (ASP.NET). Both are internet wide applications. Our clients could be anywhere in the world.</p>