> but then I have to make my own libraries for all languages that I want to offer end-to-end encryption for.

Do C (or something where the mapping to C is known), and lots of languages have FFI libs where wrapping that is fairly trivial, reducing the need to make your own libraries for all languages.

Or do a tool with a CLI, and other langs can call that.

Ideally, your primary implementation does both of those, making it easy to wrap and call. That's how things like GPG are so widely supported.

That is an interesting idea, yet still a lot of work, sadly. I was hoping somebody had done the legwork already. I looked at Tink [1] and age [2] based on my co-worker's recommendation, but they all seem to have limited implementations in other languages.

[1] https://github.com/google/tink

[2] https://github.com/FiloSottile/age