[Feature request] Verify PDF certificate signature

[maxi322]

The tool lets you create signatures with certificates but there is currently no way to verify them.

An elegant solution would be to include such a functionality within the reader.

[sbplat]

If you're referring to checking if the certificate is trusted or not, then it wouldn't be possible since some certificates are self signed. Everything else should definitely be achievable though.

[maxi322]

True, but an option would be to include an optional custom trust store file like a NSS certificate database.
When this is not included it could use the mozilla one for example and only verify official certificates.

[lucifer-woo]

This seems similar to JakubMelka/PDF4QT#161

Maybe OCSP based revocation checking instead of trusting would be a better option. I think it should be implemented in the PDF reader mostly and also separately to print it with validated signature.

[lucifer-woo]

I found this tool called mupdf and it has the abilites to do so. Seems to be what we are looking for.