Digital signature is valid in desktop computer but the same pdf file saved in Google drive states as unknown validity. Why?

Please clarify, when you viewed the PDF in Google Drive, do you mean you viewed it in the Google Drive preview? Or did you view it in your browser’s built-in (or extension) PDF viewer? Or did you fully download the file and open it in Acrobat Reader again?

Furthermore, where did you see that “validity unknown” message? Was it in the document area of the viewer? Or was it in a separate signature panel?

I ask because most previewers and built-in browser PDF viewers don’t validate signatures. Thus, in any such viewer you wouldn’t see a validation result by those viewers at all.

If in such a viewer you see something like a validation result nonetheless, and if that result is in the document area of the viewer, then the signature most likely is of a type that has been deprecated more than 20 years ago:

At the beginning of the century Acrobat introduced PDF signatures with visualizations in the document area itself that would show the validation result (green tick / yellow question mark / red cross) overlaying or underlaying the simple signature appearance. Those signatures were stored in the document with the “validity unknown” state (yellow question mark) active, so a PDF viewer not supporting such signatures will display the signature like that.

Adobe soon deprecated this kind of signatures as such an in-document signature appearance can easily be spoofed. But Acrobat still handles those old signatures for compatibility reasons.

Hi Joe Rathinam,

Thank you for reaching out.

As mentioned, after downloading the document to your desktop, it opens as valid. However, when you upload the document to Google Drive, it shows with unknown validity. Could you please confirm how you are opening this document? 

It would be helpful if you could provide a screen recording showing what happens. You can send the video in a private message, and we will investigate this behaviour.

Thanks,

Meenakshi