{ideas}

When you develop WCF services you might want to have some protected and unprotected methods on the same service. To do this you will need to do as follows.
Publish your service on an unprotected area of your site; change your web.config file to do it:

<location path="services">
    <system.web>
        <authorization>
            <allow users="*" />
        </authorization>
    </system.web>
</location>

Add this line of code to your service constructor method:

public Service()
{
    Thread.CurrentPrincipal = HttpContext.Current.User;
}

Finally use declarative permissions on the service methods you want to protect:

[PrincipalPermission(SecurityAction.Demand)]
public String YourMethod()
{
    return String.Empty;
}