public void Sign(String src, String name, String dest, X509Certificate[] chain,
ICipherParameters pk, String digestAlgorithm, PdfSigner.CryptoStandard subfilter,
String reason, String location)
{
PdfReader reader = new PdfReader(src);
PdfSigner signer = new PdfSigner(reader, new FileStream(dest, FileMode.Create), new StampingProperties());
// Create the signature appearance
PdfSignatureAppearance appearance = signer.GetSignatureAppearance();
appearance
.SetReason(reason)
.SetLocation(location);
// This name corresponds to the name of the field that already exists in the document.
signer.SetFieldName(name);
// Get the background layer and draw a gray rectangle as a background.
PdfFormXObject n0 = appearance.GetLayer0();
float x = n0.GetBBox().ToRectangle().GetLeft();
float y = n0.GetBBox().ToRectangle().GetBottom();
float width = n0.GetBBox().ToRectangle().GetWidth();
float height = n0.GetBBox().ToRectangle().GetHeight();
PdfCanvas canvas = new PdfCanvas(n0, signer.GetDocument());
canvas.SetFillColor(ColorConstants.LIGHT_GRAY);
canvas.Rectangle(x, y, width, height);
canvas.Fill();
// Set the signature information on layer 2
PdfFormXObject n2 = appearance.GetLayer2();
Paragraph p = new Paragraph("This document was signed by Bruno Specimen.");
new Canvas(n2, signer.GetDocument()).Add(p);
IExternalSignature pks = new PrivateKeySignature(pk, digestAlgorithm);
// Sign the document using the detached mode, CMS or CAdES equivalent.
signer.SignDetached(pks, chain, null, null, null, 0, subfilter);
}
