public async Task CheckCertUpdate()
        {
            try
            {
                if (DeviceInfo.Connectivity.InternetReachability == NetworkReachability.NotReachable)
                {
                    return;
                }

                string certHash = await Pkcs12FileHelper.GetSha1Hash();

                if (certHash != null)
                {
                    string remoteHash = await GetRemoteCertificateHash();

                    if (remoteHash == null)
                    {
                        DialogHelper.ShowAlertOK(AppResources.APP_TITLE, AppResources.CERT_UPDATE_FAILED);
                        return;
                    }

                    if (!certHash.Equals(remoteHash, StringComparison.OrdinalIgnoreCase))
                    {
                        bool yes = await DialogHelper.ShowConfirm(AppResources.APP_TITLE, AppResources.CERT_UPDATE_AVAILABLE);

                        if (yes)
                        {
                            Device.BeginInvokeOnMainThread(() =>
                            {
                                Application.Current.MainPage = new CertPage();
                            });
                        }
                    }
                    else
                    {
                        DialogHelper.ShowAlertOK(AppResources.APP_TITLE, AppResources.CERT_UPDATE_NOT_REQUIRED);
                    }
                }
            } catch (Exception)
            {
                DialogHelper.ShowAlertOK(AppResources.APP_TITLE, AppResources.CERT_UPDATE_FAILED);
            }
        }