An ASP.Net web site, that resides on a web server along with it's Microsoft Access Database
And an ASP.Net web service that connects the two; it resides on the web server along with the database, the windows app. requests information from the web service and the web service provides the information
What I need to do is making the web service more secure; I thought of putting a password, and the windows application must provide the password everytime it calls a method in the web service. But a more "modern" way would be getting advantage of the Globalized Unique Identifier (GUID). It's so easy to generate from VB.Net and even from ASP.Net, but how can I use GUID to Authenticate that the web service is being called from my windows application and not from any other application?
And is there any other way to reach my goal other than using GUID??