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c#itextdigital-signatureacrobatpkcs#7

How to remove validity unknown icon from signature field using itextsharp C#?

How to remove validity unknown icon(question mark) from signature field before calculating the hash of pdf.

Below code that I am using to create signature field.

PdfStamper stamper = PdfStamper.CreateSignature(reader, os, '\0');
PdfSignatureAppearance appearance = stamper.SignatureAppearance;
appearance.SignDate = DateTime.Now.AddMinutes(15);
appearance.Reason = reasonForSign;
appearance.Contact = "";
appearance.Location = locationToShowOnSignatureStamp;
appearance.Acro6Layers = false;
appearance.Image = null;
appearance.SignatureRenderingMode = PdfSignatureAppearance.RenderingMode.DESCRIPTION;
appearance.CertificationLevel = PdfSignatureAppearance.NOT_CERTIFIED;
appearance.SetVisibleSignature(new iTextSharp.text.Rectangle(10, 10, 149, 69), reader.NumberOfPages, "s1");

Solution

  • Your code explicitly requests that icon: you use

    appearance.Acro6Layers = false;

    This instructs itext to create signature appearances as Adobe Acrobat up to version 5 did. This includes "layers" for signatures with positive, inconclusive, or negative validation results. If you use

    appearance.Acro6Layers = true;

    instead (which is the default), itext creates signatures for which Adobe Acrobat won't show such on-page visualizations of the validation result anymore.