What you are looking for is local peer-to-peer file sharing. When I was studying, we used eMule, but that is for Windows and old. I don't have a concrete software suggestion, but looking around the gnutella protocol could be promising.
Edit: QuantumCogs suggestion is also good, the use cases are slightly different.
Honorable mention: the GNU Taler project
https://taler.net/en/index.html
Could be a better alternative to crypto.
To me the answers are useful enough and I appreciate that it understands vague questions. When I don't know enough about a topic to know what terms to punch into a search engine, I can use ChatGPT as a first step and go from there.
Maybe make it look like a spam email? :-)
Write a web server with a countdown that sends you regularly a link via email to reset the countdown.
That's the first thing I thought about when I saw this post. As a kid I loved the secrets in this game. I don't know if it just seems so because I'm not a child anymore but modern games don't seem to have this kind of mystery.
You could use React Native, so the language would be Javascript / Typescript.
Take a look at "Lovers in a dangerous spacetime". It's a cute, fun coop game with fairly simple controls. And I'm pretty sure it was developed with non-gamer partners in mind.
Unfortunately, I don't have a proper source. When I saw this post, the warning from reddit came to my mind and from the answers here I was surprised how many people open drives.
I assume, it is per hard drive such a negligible amount, that it could theoretically matter over a long time if you open a lot but that there is probably not a single medical proven case and the warning from reddit was overly cautious.
Edit: I found the post and comment. The issue mentioned was the cobalt. https://www.reddit.com/r/pics/comments/17il3i3/comment/k6veo9c/?utm_source=share&utm_medium=web2x&context=3
Edit2: I went and searched a bit. This meta-analysis says they found no increased cancer risk for exposure to cobalt particles. https://www.sciencedirect.com/science/article/pii/S0273230021001288
As far as I know, the idea with holding gold in bank storage is, that if hyperinflation occurs, the currency becomes worthless and there will be economic upheaval, but it will not be the apocalypse. And then a new currency will be created and everybody who held physical assets instead of the old currency will be in a way better position.
I don't want to ruin your fun, but the last time I saw a post like this on reddit, the top comment was: "Don't open hard drives. They contain micro particles from wear and tear, that are as dangerous as asbestos."
Edit: I found the post and comment. The issue mentioned was the cobalt. https://www.reddit.com/r/pics/comments/17il3i3/comment/k6veo9c/?utm_source=share&utm_medium=web2x&context=3
Edit2: I went and searched a bit. This meta-analysis says they found no increased cancer risk for exposure to cobalt particles. https://www.sciencedirect.com/science/article/pii/S0273230021001288
https://proton.me/pass