pdf-sign-check VS scanyourpdf

Very nice! I've also implement a similar project that can be used to not only sign documents but also check the validity of signed documents through a simple API: https://github.com/spapas/pdf-sign-check

We use it for many years in a public sector organisation to make sure that our internal documents are properly signed.

For a project that you can use to actually sign (electronically of course) a PDF file or verify that a PDF file has a proper signature take a look a this:

https://github.com/spapas/pdf-sign-check

It uses org.bouncycastle and apache pdfbox and is completely open source. I'd be happy to help anybody that wants to use it in his organization!

This being said, assuming you don't need a searchable text layer on the special slide in question added as image/pdf, you may alter the appearance as if it were about an old, used paper by additional noise, blur, random rotation, gray scale replacing colors, etc. Implementations already in the field include lookscanned.io (with a repository on GitHub), scanyourpdf (their source code), or closed source supertool).

There is a version - it's been posted on HN before: https://github.com/baicunko/scanyourpdf

https://news.ycombinator.com/item?id=23157408

Github repo: https://github.com/baicunko/scanyourpdf

But yeah, the security implications of uploading a PDF with your SSN and signature to a random website is, um, not good.

It's open source, so anybody can look through what the code does on the GitHub page. I'm not sure how to verify that the code on the GH page is the same as the code running on the website, but I'm asking the author and I'll get back to you.