Multiple Signatures, adding more signature invalidades the external signature.

[Frederico Santos]

Hi Team,

I have a situation that I cannot resolve.

I am using syncfusion license,so it is not a license issue.

I have a PDF that is signed by external signature. Where I insert a blank signature on the PDF, then calculate the hash, finally I replace the calculated hash for the final signature hash. (basically the logic in this example:

syncfusion example

This works no problem. In the end PDF is a correctly signed PDF with one signature.

And using the example in apply-one-or-more-digital-signatures, I can add multiple local signatures to a PDF.

Now I need to combine both examples, but I not able to do so. Need help.

I need to add more signatures to the PDF signed externaly, but when I do the signature say, “Document has been altered or corrupted since it was signed.”

I also fund this topic on the forum problemwithacrobat.

and I have a similar situation. if I do ValidateSignatures, its say "All signatures are valid"

but if I open the PDF in acrobatIX I get:

thx in advance

Attachment: example_c383dcc8.zip

[Jeyalakshmi Thangamarippandian]

Currently we are validating on this and will update the further details on February 8th, 2024.

[Jeyalakshmi Thangamarippandian]

Currently we are still analyzing on your requirement, and we will update further details on February 12^th, 2024.

[Jeyalakshmi Thangamarippandian]

"After further analysis, we found that the reported issue was replicated in the documents provided. However, when we attempted to add a new signature after the external signature, the issue did not replicate on our end. Additionally, we suspect that there may have been a problem with the way the external PDF was created.

 

Therefore, we kindly request that you share your input document and the code snippet used for converting the externally signed PDF document for further investigation. We have also attached a sample for your reference."

 

Sample : https://www.syncfusion.com/downloads/support/directtrac/general/ze/Modifiedsample1214295838

[Frederico Santos]

hi team,

thank for you anser, in the zip file are the requested files

Attachment: requested_info_317c11d8.zip

[Jeyalakshmi Thangamarippandian]

Thanks for the update.

Currently we are still analyzing on your requirement, and we will update further details on February 19^th, 2024.

[Frederico Santos]

Hi, 

I got to work.

It was the PDF that was broken. I use syncfusion to fix the PDF.

" we suspect that there may have been a problem with the way the external PDF was created."

thanks

[Jeyalakshmi Thangamarippandian]

We are glad to hear, please get back to us if you need any further assistance on this. We always happy to assist you.