I don’t want to be discovered. I want to give you my pseudonymous pointer and you can ping me to connect.
Using phone numbers to ‘discover’ doesn’t solve the problem you say prevented encrypted email adoption, that’s a next step in the dance.
There are exactly two pseudonymous identifiers that have "made it". Both associated to technological revolutions. One is phone numbers, the other is email. You put them on business cards and save them in your contacts.
This is strong evidence that this is a hard problem. No other identifiers have been successful long term.
And yes, this absolutely prevents encrypted email adoption. Imagine if switching to encrypted was like installing signal (back in the SMS fall back days).
It's: "Hey use this email client, it automatically detects when the person you're mailing also has an encryption capable client and then all your communication with that person is encrypted."
vs.
"Hey use this EMail client, and if you find out that someone you know is also using it, you can go to this menu item here and search this database in order to find out how to email them securely, and if that doesn't work just email them normally to get a public key from them, before you send them the document you wanted to send."
No guarantee that the former would work, but it would have a fighting chance.
Of course such a solution isn't possible partly due to usage patterns that email has that would break. But that's why I'm relatively forgiving of Signals strict stance on shooting down these type of feature requests. Because they actually have massively improved secure communication for more than a billion people.
On the contrary, this is precisely the discovery many users do not want. 1. Someone you know can discover you’re using this channel. 2. You can’t use the same channel both overtly and with deniability. I should be able to have as many faces for speech as I choose.
If you need deniable encryption today use WhatsApp. Done.
By way of analogy: In every HN thread about Firefox there are dozens of comments by people who say that they just couldn't use Firefox because page loads are so awfully slow.
Consider that for a second: HN readers are willing to give their entire browsing history to Google in return for at the very worst a few dozen microseconds of load time saved.
The equivalent here is, that for non telephone number identifiers you have to create a whole UI for actually adding/discovering people. That's the equivalent of the few microseconds. You can argue that it's not a big deal, but it's exactly the type of friction in the ecosystem that hinders adoption ("I already have your phone number, why do I need another number to contact you? Know what, I'll just send you an SMS.").
And it's exactly the type of UI/UX problem that prevented encrypted email adoption ("Download a new program and some sort of key for you? I'll just send you an email directly, I'll figure this out later...").