Digital Signatures/Certificates broken when merging PDFs

[ZacCliff92]

Hello,

In our Production environments, we are trying to perform a merge on multiple PDF documents from our clients that have been digitally signed.

What seems to be happening is once the merge has completed, the signatures in the resulting PDF document have been corrupted which can cause issues with loading the Document into the PDF Document constructor in process memory for our application as well as opening the resulting document in any PDF reader other than Adobe Reader.

Not to mention having the document digital signatures become corrupted during the merge process essentially invalidates signatures for very important documents from our clients which cannot happen.

Do you have a solution for how to deal with maintaining digital signatures from child documents merged into a single parent document?

Given the situation, if we cannot find a resolution for this we will have to look at a different tool for our Production PDF creation/conversion.

Thank you,
Zac

[Marcia.Zhou]

Hello,

Thanks for your inquiry!

Kindly note that the signature in the PDF is used to guarantee the authenticity and to provide proof of the original and unmodified of it. The merging PDF files operation is achieved by redrawing the contents of the original PDF files to a new file. This process is equivalent to modifying the file, if the merge files contains signed PDF files, the signature of these files is not for the generated new file, so the signature will be invalid in the final file. Even if you use Adobe to merge the files, the signature will be invalidated, and the same to our Spire.PDF. Hope you can understand.

If you want to put all PDF files into one PDF file while maintaining the validity of the signature. Please refer to the following code to merge them as a PDF portfolio.

Code: Select all

            String[] files = new String[] { "E:\\testdoc\\SimpleSign.pdf", "E:\\testdoc\\SimpleSign1.pdf", "E:\\testdoc\\SimpleSign2.pdf", "E:\\testdoc\\SimpleSign3.pdf" };
            PdfDocument doc = new PdfDocument();
            for (int i = 0; i < files.Length; i++)
            {
                doc.Collection.Folders.AddFile(files[i]);
            }
            //Save the document
            String result = "CreatePDFPortfolio.pdf";
            doc.SaveToFile(result);


Sincerely,
Marcia
E-iceblue support team

[Marcia.Zhou]

Hello,

Hope you are doing well!

Has the issue been solved now? Could you please give us some feedback at your convenience?

Thanks in advance.

Sincerely,
Marcia
E-iceblue support team