private void signWithoutTimeStampAuthority(PdfStamper stamper)
{
var signAppearance = stamper.SignatureAppearance;
signAppearance.Reason = SignatureData.SigningInfo.Reason;
signAppearance.Contact = SignatureData.SigningInfo.Contact;
signAppearance.Location = SignatureData.SigningInfo.Location;
addVisibleSignature(signAppearance, stamper);
signDetached(signAppearance);
}