@03d37794 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. 

 @93d37991 I guess I've seen on the bank website statements like "Beware of scams!".

But I'm thinking we do have the technology to verify that a message has come from an authentic source. Why should the end user bare the load of having to decipher whether the message is legitimate or not.

At this point, I probably receive more phone calls from people trying to fake an identity, than legitimate callers.

(I spent a bunch of time encrypting XML messages, then later dealing with verifying digital passports. But that was also about 10 years ago for me too)