Digital Signature IsDocumentModified issue with Form Fields

Question

IsDocumentModified should return true if any form field is added after a digital signature as this is considered a modification in pdf file and adobe reader converts the signature to invalid with MessageDocument has been altered or corrupted since it was signedHowever with some files the

IsDocumentModified is false ... see attached filesFormField_Signature_FormField(Valid) returns true which is correctFormField_Signature_FormField(Not Valid) returns false which is not correct Attachment: test_case_f6648668.zip

Ravikumar Baladhandapani · Accepted Answer

We have included the fix for this issue “IsLtvEnabled
API not working as expected in PdfLoadedSignatureField”  in our latest weekly release (23.1.40).Please use the below link to
download our latest NuGet,NuGet Link: https://www.nuget.org/packages/Syncfusion.Pdf.WinForms/23.1.40

Ravikumar Baladhandapani · Answer

We were able to reproduce the reported issue with provided details on our end. Currently, we are validating on this and will update the further details on September 27th, 2023.

Jacobs · Answer

Thanks

Karmegam Seerangan · Answer

We have confirmed the issue “IsDocumentModified API does not working as expected for particular pdf document”as a defect in our product and we will include the fix in our upcoming weekly release which will be available on 10th October 2023 Note: If you require a patch for the reported issue in any of our Essential Studio Main or SP release version, then kindly let us know the version, so that we can provide a patch in that version based on our SLA policy. Disclaimer: “Inclusion of this solution in the weekly release may change due to other factors including but not limited to QA checks and works reprioritization.”

Jacobs · Answer

Thanks It is working fine now.

Jacobs · Answer

Dear

Ravikumar ,When adding two signatures on same file , the isdocumentmodified  became true again , while it shouldn't.so please check . Attachment: test_2signatures_27c89871.zip

Karmegam Seerangan · Answer

We were able to reproduce the reported issue with provided
details on our end. Currently, we are validating on this and will update the
further details on October 18th, 2023.

Ravikumar Baladhandapani · Answer

We have confirmed the issue “IsDocumentModified API does not work as
expected with multi-signed PDF document” as a defect in our product and we
will include the fix in our upcoming weekly release which will be available on
24th  October 2023  Please use the below feedback link to track the status of the reported
bug.IsDocumentModified
API does not work as expected with multi-signed PDF document in WinForms |
Feedback Portal (syncfusion.com)Note: If you require a patch for the reported issue in any of our Essential
Studio Main or SP release version, then kindly let us know the version, so that
we can provide a patch in that version based on our SLA policy.Disclaimer: “Inclusion of this solution in the weekly release may change
due to other factors including but not limited to QA checks and works
reprioritization.”

Ravikumar Baladhandapani · Answer

We
have included the fix for this issue “IsDocumentModified
API does not work as expected with multi-signed PDF document” in our latest weekly release (23.1.42).Please use the below link to
download our latest NuGet,Nuget Link: NuGet
Gallery | Syncfusion.Pdf.WinForms 23.1.42

Jacobs · Answer

Thanks, the previous issue is fixed but unfortunately i found

two

other issueswhen adding form field after signature added by syncfusion ... the isdocumentmodified returns false while it should be truethis does not happen if signature was added by Adobe

... the isdocumentmodified returns true which is correct. another issue with QR code, it is converted to its value after signed by syncfusion sometimes from first signature and sometimes from second signature

this also does not happen if signature was added by Adobe Also PDFViewer Control does not display some form field like QR Code see attached filesAttachment: testcases_29102023_211973c7.zip

Ravikumar Baladhandapani · Answer

when adding form field after signature added by syncfusion ...
  the isdocumentmodified returns false while it should be true
  this does not happen if signature was added by
  Adobe   ... the isdocumentmodified returns true which is
  correct.

We have confirmed the issue “IsDocumentModified API does not
  work as expected while adding multiple fields” as a defect in our
  product and we will include the fix in our upcoming weekly release which will
  be available on 7th November 2023
    
  Please use the
  below feedback link to track the status of the reported bug.
  https://www.syncfusion.com/feedback/48060/isdocumentmodified-api-does-not-work-as-expected-while-adding-multiple-fields
   
  Note: If you
  require a patch for the reported issue in any of our Essential Studio Main or
  SP release version, then kindly let us know the version, so that we can
  provide a patch in that version based on our SLA policy.
   
  Disclaimer:
  “Inclusion of this solution in the weekly release may change due to other
  factors including but not limited to QA checks and works reprioritization.”

another issue with QR code, it is converted to its value after
  signed by syncfusion sometimes from first signature and sometimes from second
  signature 
  this also does not happen if signature was added by Adobe

Could you
  please share the complete code snippet or simple sample  to reproduce
  the issue, it will be helpful for our further investigation.

Also PDFViewer Control does not display some form field like QR
  Code

We have sent the details to the corresponding team. Right
  now, They are looking into this . We'll provide more information on November
  2nd, 2023.

Sowmiya Loganathan · Answer

At present, we do not have
support for viewing Form Fields in Winforms Pdfviewer. However, we can achieve
this by flattening the form fields before loading the document into the Pdfviewer
control. Flattening converts them into a graphics. We have attached sample for
your reference.Please refer the below code
snippet.

PdfLoadedDocument
  pdfLoadedDocument = new PdfLoadedDocument(@"QR1.pdf");
  pdfLoadedDocument.Form.Flatten
  = true;
  //Initializing
  the PdfViewerControl
  PdfViewerControl
  pdfViewerControl1 = new PdfViewerControl();
  //Add
  PdfViewerControl to the FormControls.Add(pdfViewerControl1);
  //Loading
  the document in the PdfViewerControl
  pdfViewerControl1.Load(pdfLoadedDocument);

Sample
link: https://www.syncfusion.com/downloads/support/directtrac/general/ze/sample1675705724

Ravikumar Baladhandapani · Answer

We have included the
fix for this issue “IsDocumentModified
API does not work as expected while adding multiple fields”  in our
latest weekly release (23.1.44). Please use the below link to download
our latest NuGet,Nuget Link: NuGet
Gallery | Syncfusion.Pdf.WinForms 23.1.44

Jacobs · Answer

Dear

Ravikumar

i am still having issues with property isdocumentmodified ... it is converted to true in these two cases pdf with annotation comment then sign with syncfusion then add another comment

isdocumentmodified becomes true however it should be false

pdf with annotation comment then sign with syncfusion then add a reply to same comment  isdocumentmodified becomes true however it should be false

while with using annotation highlight before and after signature deosnot cause issues and

isdocumentmodified  stays falsethese issues does not happen if i sign with adobe reader (

isdocumentmodified stays false in all cases)please check the attached files ... also if you can test all other annotation fields Attachment: testcasesisodcumentmodified_c714fb2f.zip

Jeyalakshmi Thangamarippandian · Answer

Currently we are
analyzing on this and will update the further details on February 12th, 2024.

Jeyalakshmi Thangamarippandian · Answer

The reported issue still need a lot more in-depth research; thus we are looking into them. On 13th  February 2024, further information will be updated.

RaashithAhamed SahulHameed · Answer

We have confirmed the issue “isdocumentModify becomes false after adding comments in the pdf” as a defect in our product and we will include the fix in
weekly release on 27th February 2024Please use
the below feedback link to track the status of the reported bug.https://www.syncfusion.com/feedback/50912/isdocumentmodify-becomes-false-after-adding-comments-in-the-pdfNote: If
you require a patch for the reported issue in any of our Essential Studio Main
or SP release version, then kindly let us know the version, so that we can
provide a patch in that version based on our SLA policy.Disclaimer:
“Inclusion of this solution in the weekly release may change due to other
factors including but not limited to QA checks and works reprioritization.”

Jacobs · Answer

Thanks ... but i want to confirm that the correct behavior that IsDocumentModified should stay false ... as described in my reply

RaashithAhamed SahulHameed · Answer

Sorry for the inconvenience caused, Yes It should be false after adding comments in the pdf

Jeyalakshmi Thangamarippandian · Answer

We have included the fix for this issue “isdocumentModify becomes true after adding comments in the pdf” fix in our latest weekly release (24.2.8).Please download the Nuget from the below link

Nuget Link: NuGet Gallery | Syncfusion.Pdf.WinForms 24.2.8

Root cause:

We discovered the issue while checking the updated objects along with comment-type objects during validation. This is why the problem occurred.