iTextSharp.text.pdf.PdfSignatureAppearance.AddFieldMDP C# (CSharp) Метод

        private void AddFieldMDP(PdfDictionary crypto, PdfDictionary fieldLock)
        {
            PdfDictionary reference = new PdfDictionary();
            PdfDictionary transformParams = new PdfDictionary();
            transformParams.Merge(fieldLock);
            transformParams.Put(PdfName.TYPE, PdfName.TRANSFORMPARAMS);
            transformParams.Put(PdfName.V, new PdfName("1.2"));
            reference.Put(PdfName.TRANSFORMMETHOD, PdfName.FIELDMDP);
            reference.Put(PdfName.TYPE, PdfName.SIGREF);
            reference.Put(PdfName.TRANSFORMPARAMS, transformParams);
            reference.Put(new PdfName("DigestValue"), new PdfString("aa"));
            PdfArray loc = new PdfArray();
            loc.Add(new PdfNumber(0));
            loc.Add(new PdfNumber(0));
            reference.Put(new PdfName("DigestLocation"), loc);
            reference.Put(new PdfName("DigestMethod"), new PdfName("MD5"));
            reference.Put(PdfName.DATA, writer.reader.Trailer.Get(PdfName.ROOT));
            PdfArray types = crypto.GetAsArray(PdfName.REFERENCE);
            if (types == null)
                types = new PdfArray();
            types.Add(reference);
            crypto.Put(PdfName.REFERENCE, types);
        }