public void Sign3(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());

            PdfSignatureAppearance appearance = signer.GetSignatureAppearance();

            appearance.SetReason(reason);
            appearance.SetLocation(location);
            signer.SetFieldName(name);

            // Set a custom text and background image
            appearance.SetLayer2Text("This document was signed by Bruno Specimen");
            appearance.SetImage(ImageDataFactory.Create(IMG));
            appearance.SetImageScale(1);

            PrivateKeySignature pks = new PrivateKeySignature(pk, digestAlgorithm);

            signer.SignDetached(pks, chain, null, null, null, 0, subfilter);
        }