diff --git a/include/qpdf/QPDFAcroFormDocumentHelper.hh b/include/qpdf/QPDFAcroFormDocumentHelper.hh index 8be4d069..f9ad0091 100644 --- a/include/qpdf/QPDFAcroFormDocumentHelper.hh +++ b/include/qpdf/QPDFAcroFormDocumentHelper.hh @@ -163,6 +163,11 @@ class QPDFAcroFormDocumentHelper: public QPDFDocumentHelper QPDF_DLL void generateAppearancesIfNeeded(); + // Disable Digital Signature Fields. Remove all digital signature fields from the document, + // leaving any annotation showing the content of the field intact. + QPDF_DLL + void disableDigitalSignatures(); + // Note: this method works on all annotations, not just ones with associated fields. For each // annotation in old_annots, apply the given transformation matrix to create a new annotation. // New annotations are appended to new_annots. If the annotation is associated with a form diff --git a/libqpdf/QPDFAcroFormDocumentHelper.cc b/libqpdf/QPDFAcroFormDocumentHelper.cc index f2daa0c7..5fdd20ba 100644 --- a/libqpdf/QPDFAcroFormDocumentHelper.cc +++ b/libqpdf/QPDFAcroFormDocumentHelper.cc @@ -415,6 +415,28 @@ QPDFAcroFormDocumentHelper::generateAppearancesIfNeeded() setNeedAppearances(false); } +void +QPDFAcroFormDocumentHelper::disableDigitalSignatures() +{ + std::set to_remove; + auto fields = getFormFields(); + for (auto& f: fields) { + auto ft = f.getFieldType(); + if (ft == "/Sig") { + auto oh = f.getObjectHandle(); + to_remove.insert(oh.getObjGen()); + // Make this no longer a form field. If it's also an annotation, the annotation will + // survive. If it's only a field and is no longer referenced, it will disappear. + oh.removeKey("/FT"); + // Remove fields that are specific to signature fields. + oh.removeKey("/V"); + oh.removeKey("/SV"); + oh.removeKey("/Lock"); + } + } + removeFormFields(to_remove); +} + void QPDFAcroFormDocumentHelper::adjustInheritedFields( QPDFObjectHandle obj,