nostr:npub1q0fh099yrljs7rxztzlylu9edzy2y3yt492kaajvfhm76kzugaxskurdcz you could use it, I used to do it over email in the 90s and early 2000s, but it doesn't solve the problem of banks etc not employing it. Why would they bother? They have no incentive and more likely to invent their own solution.

There's also the issue with key verification and the high processing requirements (might not be an issue now), and that it's not the best solution for the job. It's as much a social engineering issue as a technical one.

There are other problems too, but I can't remember what they are. It's been ten years since I did much cryptography.