(Hi, disclaimer: I'm one of the current dangerzone maintainers)

You are correct: that's basically what Dangerzone is doing!

The challenges for us are to have a sandbox that keeps being secure and make it possible for non-tech folks (e.g. journalists) to run this in their machines easily.

About the sandbox:

- Making sure that it's still updated requires some work: that's testing new container images, and having a way to distribute them securely to the host machines ;

- In addition to running in a container, we reduce the attack surface by using gVisor¹ ;

- We pass a few flags to the Docker/Podman invocation, effectively blocking network access and reducing the authorized system calls ;

Also, in our case the sandbox doesn't mount the host filesystem in any way, and we're streaming back pixels, that will be then written to a PDF by the host (we're also currently considering adding the option to write back images instead).

The other part of the work is to make that easily accessible to non-tech folks. That means packaging Podman on macOS/Windows, and providing an interface that works on all major OSes.

¹ https://dangerzone.rocks/news/2024-09-23-gvisor/

Why not upload to Google docs and view there? Way less work.

Yep. A static image would be better, although I'd also prefer the option of getting a simple text file so that I can get the URLs out of hyperlinks.