Email these days is however tied to DKIM and domains. We have UI problems, but communicating to a companies email servers at their domain name can be reasonably expected to be communicating with that company.

It's just the security story on that if you never want the content disclosed isn't great, but conversely, conceptual entity communications are always going to be a bit public by nature.

There's a whole other rant I have about this problem, where we really lack domain specific trust standards - i.e. communicating with a business, what I want to know is "is this a recognized legal business entity in it's jurisdiction, and what's it's status to mine?" which is very different to "I need to make absolutely sure me and John Smith's communication is just between us" - but they're in the same space of problem.

> There's a whole other rant I have about this problem, where we really lack domain specific trust standards - i.e. communicating with a business, what I want to know is "is this a recognized legal business entity in it's jurisdiction, and what's it's status to mine?"

I have the same pain, but this seems more like a regulatory issue than a technological one. Here in Germany, (basically all) legal entities need to publish a physical adress where they are reachable, it would be easy, in theory, to extend this to a reachable domain or email adress, thereby giving a guarantee, at least in Germany, that you are interacting with the business you are expecting. As you said, DKIM already exists.

Unless I have missed your point, then rant away.

DKIM is an anti-spam tool, not an end-to-end encryption tool (obviously, it's not end-to-end at all, and if you're relying on it, you might as well forget about message encryption, because you've simply decided to trust your server).