We're sorry Aspose doesn't work properply without JavaScript enabled.

Free Support Forum - aspose.com

PDF/A became invalid after multiple digital signature

The conversion from PDF to PDF/A has some problem.
The situation is as follows, when digitally signing a PDF and then convert to PDF/A using Aspose and if you make at least two digital signatures, with save between them, the first signature becames invalid after the second.

If I repeat the same process but using a PDF/A taken from another program(just open and save), both signatures are still valid after.

1_0-Aspose_WordToPDF_ToPDFA.pdf (21.5 KB)
1_1-Output_Error.pdf (62.9 KB)
2_0-Aspose_WordToPDF_ToPDFA_OpenAndSaveWithOtherProgram_OK.pdf (21.5 KB)
2_1-Output_OK.pdf (65.8 KB)


Could you kindly share a sample code snippet as well for our reference. We will test the scenario in our environment and address it accordingly.

Project.zip (64.5 KB)

I attach an example.
The pfx file and password were not included.

NOTE: It does not happen with all files, however the first signature is always valid.


While testing the scenario at our end using Aspose.PDF for .NET 21.3, we faced and Exception i.e. System.ArgumentException: 'Array may not be empty or null. The exception occurred during signing the PDF first time. Could you please verify by testing the scenario using the latest version of the API? We will log an issue in our issue tracking system and share the ID with you.

Before you run the test you have to change the SignFile method and specified a valid pfx path and the respective password, if you do not change anything you will get the System.ArgumentException.
The real error I am reporting is after that.

I cannot send the pfx and password for security reasons.


Previously we tested the scenario using your PFX file that you shared in your response. Nevertheless, we have been able to notice the issue by using one of our .pfx files. Therefore, it has been logged as PDFNET-49740 in our issue tracking system. We will further look into its details and keep you posted with the status of its correction. Please be patient and spare us some time.

We are sorry for the inconvenience.


After two and a half months, any news about this error?


The issue is currently under the phase of investigation and we are afraid that it is not yet resolved. Please note that it will be fixed on first come first serve basis and we will surely inform you in this forum thread as soon as we have some more updates about its resolution. Please be patient and give us some time.

We are sorry for the inconvenience.

The issues you have found earlier (filed as PDFNET-49740) have been fixed in Aspose.PDF for .NET 21.7.