Architecture for natively authenticating a client application to a web server via HTTP authentication. The Web Services Architecture, and more specifically, Web Services Security, is leveraged to enable legacy applications to access web services transparently to the existing legacy applications. A security support provider (SSP) is created that employs WS-* protocol to at least emulate ws-trust and ws-mex thereby enabling policy exchange via an HTTP protocol stack. Policy can be exchanged via a WWW-Authenticate header enabling legacy applications to use the WS-* family of protocols without modifying the client application. The WS-* protocols are abstracted into a generic programming interface for native client application use.