/// <summary>
/// Sign (fill) named field in the document soft way (using existing stamper)
/// </summary>
/// <param name="stamper">PdfStamper</param>
/// <param name="fieldName">Field to be signed</param>
/// <param name="reason">Sign reason</param>
/// <param name="location">Sign location</param>
/// <param name="graphics">Sign graphic</param>
/// <param name="certFile">PFX certificate</param>
/// <param name="certPassword">password of certificate</param>
/// <param name="renderingMode">SignatureRender renderingMode</param>
/// <param name="certificationLevel">PdfSignatureAppearance Certification Level</param>
/// <returns>Successfull or not</returns>
public static bool SignField(ref PdfStamper stamper,
string fieldName,
string reason,
string location,
Bitmap graphics,
string certFile,
string certPassword,
PdfSignatureAppearance.SignatureRender renderingMode = PdfSignatureAppearance.SignatureRender.GraphicAndDescription,
int certificationLevel = PdfSignatureAppearance.CERTIFIED_NO_CHANGES_ALLOWED)
{
bool result = false;
try
{
if (stamper.Reader.AcroFields.Fields.ContainsKey(fieldName))
{
PdfSignatureAppearance psa = GetPSA(fieldName, stamper, graphics, reason, location, renderingMode, certificationLevel);
Pkcs12Store store = new Pkcs12Store(new FileStream(certFile, FileMode.Open), certPassword.ToCharArray());
string alias = "";
ICollection <X509Certificate> chain = new List <X509Certificate>();
foreach (string al in store.Aliases)
{
if (store.IsKeyEntry(al) && store.GetKey(al).Key.IsPrivate)
{
alias = al;
break;
}
}
AsymmetricKeyEntry ake = store.GetKey(alias);
foreach (X509CertificateEntry c in store.GetCertificateChain(alias))
{
chain.Add(c.Certificate);
}
RsaPrivateCrtKeyParameters parameters = ake.Key as RsaPrivateCrtKeyParameters;
psa.SetCrypto(parameters, chain.ToArray(), null, PdfSignatureAppearance.WINCER_SIGNED);
result = true;
}
else
{
result = false;
}
}
catch (Exception e)
{
Console.WriteLine(e.Message);
result = false;
}
return(result);
}
private static PdfSignatureAppearance GetPSA(string fieldName,
PdfStamper stamper,
Bitmap graphics,
string reason,
string location,
PdfSignatureAppearance.SignatureRender renderingMode,
int certLevel)
{
PdfSignatureAppearance psa = stamper.SignatureAppearance;
psa.Acro6Layers = true;
psa.SignatureGraphic = iTextSharp.text.Image.GetInstance(graphics, ImageFormat.Png);
psa.Render = renderingMode;
psa.CertificationLevel = certLevel;
psa.Reason = reason;
psa.Location = location;
psa.SetVisibleSignature(fieldName);
return(psa);
}