NightFantom

I usually (but not often enough tbh) refer to owasp documentation, like this one https://cheatsheetseries.owasp.org/cheatsheets/Cryptographic_Storage_Cheat_Sheet.html They basically say elliptic curves for asymmetric encryption, or RSA with a key of at least 2048 bits

Thanks!

Got any links to resources you used / recommend for this / further reading?

Doesn’t work on my phone (made for an older version of android) but it looks like the game “set”, and googling that I found this: https://play.google.com/store/apps/details?id=com.nelis.set (haven’t tried it yet but it has the tag “offline” so looks good)