[FIXED] PDF document: How to verify the digital signature using python?

Issue

We are doing the RPA project and extract the data PDF to excel using python. Now we need verify the digital_signature in PDF.

Solution

According to PDF 1.7 spec a document may contain:

• one or more approval signatures
• at most one certification signature
• at most two usage rights signatures

There are also 2 defined digest computing techniques. So there is no short answer and checking digital signatures might be tricky.

See PDF 1.7 section 12.8 Digital Signatures

As far as I know there is no ready-to-run python library to check all possible PDF signatures. You may try to use pdfreader to browse PDF document structure and to compute and check the signatures. See few examples

Answered By - Maksym Polshcha