I wrote a project to do this a few years ago[1], it's mainly missing an automated mechanism to scan the PDFs and a GUI. Maybe you'll find it interesting.
hey, this is a great idea! I'll link into your app from my readme.
I really like that the PDF contains the entire dataset, not just the keys. I see lots of little details around organizing the PDFs, like document hashes, etc, very nice job!
Since you wrote it in Rust, I'd suggest compiling it to wasm and releasing a browser-based version
> Since you wrote it in Rust, I'd suggest compiling it to wasm and releasing a browser-based version
That was my eventual plan for having a single GUI for everything, the only problem is that there isn't a really obvious way to support scanning a PDF you upload -- basically you need a pure-Rust PDF renderer and there isn't one up to the task as far as I could tell. On mobile you could scan each QR code separately (though doing this from a webapp is probably going to be a fairly awful UX and most people would prefer to photograph the whole document and get everything scanned automatically).
Actually, after my comment I took another look and it turns out that only a few months ago someone released a pure-Rust PDF renderer called hayro[1] that seems to fit exactly what I need, so I will work on finishing this bit of paperback as soon as I have some spare time. Pure image scanning (with a webcam, phone camera, or uploading a photo) will also work since QR code scanning libraries like rqrr support scanning all QR codes in an image.
[1]: https://github.com/cyphar/paperback