Wcf.svc

//WCF CODE
namespace SRS_WCF
{
    [AspNetCompatibilityRequirements(RequirementsMode = AspNetCompatibilityRequirementsMode.Required)]
    public class SRSService : ISRSService
    {
        public SRSService()
        {
            /* this line is crucial for PrincipalPermission to work */
            Thread.CurrentPrincipal = HttpContext.Current.User;
        }

        [PrincipalPermission(SecurityAction.Demand, Authenticated = true)]
        public string Test() //Throws Error
        {
            return "Hello";
        }
    }
}