How to get additional information from a signed pdf file

[areqq]

I have pdf signed on https://autenti.com/ (enclosed)
They added page with signatures:

I'm looking for idea how to get info who signed.
in binary pdf file I see:
/Filter/Adobe.PPKLite/Location()/M(D:20221125172749+01'00')/Prop_Build<</App<</Name/Autenti#20sp.#20z#20o.o.#20z#20siedzib#05#20w#20Poznaniu#20#2861-806#29#20przy#20ul.#20Zwi#19ty#20Marcin#2029#2f8.>>>>/Reason(Podpisanie dokumentu;Franek Kimono;franek.kimono@mailnesia.com;5260211104)/SubFilter/ETSI.CAdES.detached/Type/Sig>>

How to get this using pyHanko?

Test_document.pdf

[MatthiasValvekens]

Hi @areqq,

There's an embedded_signatures property on PdfFileReader that allows you to loop over the signatures in the document. The API for EmbeddedPdfSignature is available in the documentation. Not all of the properties you mention are exposed directly, but you can get access to the signature dictionary itself via the sig_object field. In other words, to get the Reason field, you'd write something like

emb_sig = r.embedded_signatures[0]
reason = emb_sig.sig_object['/Reason']