There are 3 main alternatives for creating webservices in DotNetNuke: WCF, ASMX and HttpHandler.  I would like to avoid making changes to web.config and want to be able to use a single webservice layer for most of my calls.  Finally my webservice should integrate with the native DotNetNuke security framework so that I can limit who can call specific methods.

Which webservice offering is preferred to handle these scenarios and where can I find documentation that shows how to build the webservice to take advantage of DotNetNuke security?