public JsonResult GetContactsInGroupByAjax(string id /* group Id */)
        {
            int userId = WebSecurity.GetUserId(WebSecurity.CurrentUserName);
            var userProfile = _userContext.UserProfiles.First(x => x.UserId == userId);

            UserData userData = new UserData();
            userData.PublicKey = userProfile.PublicKey;
            userData.Timestamp = DateTime.Now;
            userData.GenerateAuthenticationHash(userProfile.PrivateKey + userProfile.PublicKey + "GET/contact/group/" + id + userData.Timestamp + userProfile.PrivateKey);

            ContactEndpoint c = new ContactEndpoint();
            var contact = c.GetContactsInGroup(id, userData);

            return Json(contact, JsonRequestBehavior.AllowGet);
        }