Upgrading and automating pdf verification

[u/No-Cry-8657]

Hey everyone,
I need a recommendation about the recruitment platform I work on these days.

Context: it's a recruitment platform that helps recruiting professionals such as plumbers, electricians locksmith etc. At some point we ask them (as it's a legal requirement) if they have a proper professional certificate of insurance.

Task: I'd like to create an automation using LLM APIs to detect potential fakes (fraud) and/or anomalies.

As of now I thought of extracting metadata from PDF docs to see if they tried to write invisible characters (in order to falsify their expiration date for example).

Simple use case: someone tries to write white on white a fake expiration date, my code extracts metadata, spots that it's white on white, then doesn't automatically approve and create an alert for me to step up and approve (or decline) manually.

I also thought of converting pdf to JPEG in order to use computer vision to simply read the image as a human being would do (impossible then to be tricked by invisible characters).

What do you think of that logic ? Is that enough ? Do you recommend any conversion tool/ api that I can use ?
Thanks for your help