将文本字段添加到数字签名的 PDF 会破坏应用的签名

Question

我正在尝试使用 PDFBOX-3.0.0 将带有值的文本字段添加到数字签名文档中，该文档允许填写表单，但会使应用的签名无效。

代码

try (   InputStream resource = getClass().getResourceAsStream("SignatureVlidationTest.pdf");
            PDDocument document = Loader.loadPDF(resource);
    ) {

        PDPage page = document.getPage(0);
        page.getCOSObject().setNeedToBeUpdated(true);
        PDAcroForm acroForm = document.getDocumentCatalog().getAcroForm();

        acroForm.getCOSObject().setNeedToBeUpdated(true);

        PDTextField textBox = new PDTextField(acroForm);
        textBox.setPartialName("SampleField");
        textBox.setMultiline(true);
        textBox.setDefaultAppearance("/Helv 14 Tf 1 0 0 rg");
        textBox.setReadOnly(true);
        textBox.setValue("label");

        float pw = page.getMediaBox().getUpperRightX();
        float ph = page.getMediaBox().getUpperRightY();

        // Specify the widget annotation associated with the field
        PDAnnotationWidget widget = textBox.getWidgets().get(0);
        PDRectangle rect = new PDRectangle(pw - 110, ph - 25, 110, 25);
        widget.setRectangle(rect);
        widget.getCOSObject().setNeedToBeUpdated(true);
        widget.setPage(page);
        widget.setPrinted(true);
        widget.setReadOnly(true);

        page.getAnnotations().add(widget);
        page.getCOSObject().setNeedToBeUpdated(true);
        acroForm.getFields().add(textBox);
        document.getDocumentCatalog().getCOSObject().setNeedToBeUpdated(true);

        Set<COSDictionary> objectsToWrite = new HashSet<>();
        objectsToWrite.add(page.getCOSObject());

        document.saveIncremental(new FileOutputStream(new File(RESULT_FOLDER, "SignatureVlidationTest-ImageAnnotationAdded.pdf")),objectsToWrite );
    }