Technically, this is very nice work.
But as a security generality - email is vastly less secure* than human nature wants to assume that it is. Human nature usually wins.
*Outside of a carefully run org's own network, and a few other edge cases
But as a security generality - email is vastly less secure* than human nature wants to assume that it is. Human nature usually wins.
*Outside of a carefully run org's own network, and a few other edge cases
I don't think this has to do with "human nature" anymore than http did. It's a very important, powerful form of communication without any secure replacement. Just as we switched to https, ideally an "xmail" or the like would get created as an open standard with open software that was email with better security by default. Sadly I'm not sure we collectively have the ability to do that kind of thing any longer, powerful entities have realized it's just too attractive to lock it up. But even many open source organizations don't seem to feel like bothering. Plenty of security experts even just prefer new shiny and will spout ridiculous "move to instant messaging". So status quo rules for the foreseeable future.
We can extend email, though. Why isn't there an SMTP GETKEY command to return a PGP key corresponding to an email address? Sure, the sender might not support the same version of PGP, and sure, the connection might be intercepted (hopefully you'd not trust the output of this command except over TLS), but like most of the email system, it would be a big improvement and good enough most of the time.
For instance, once you disregard so called transactional mail and spam, real email is almost all encrypted for all practical purposes.
DKIM and DMARC also work quite well for spoofing protection, aside from the corner cases like the above.
Average Software Engineers have an outdated idea of email, formed by 1990 era Internet.
Even Russian spies use mail.ru and their emails are compromised not by SMTP MitM but by weak passwords, google for "moscow1 moscow2 password" to see what I am talking about )
Anyway. Back to the technical point. Email servers pretty much always use TLS to talk to each other. The connection may degrade to non-encrypted for backwards compatibility, unlike HTTPS. But it's vanishingly rare.
So, for all practical purposes that affect ordinary citizens: injection, scanning and sensitive information extraction, email in transit is quite secure.
If you're in IT at a carefully run org: You ditched 512-bit keys years ago. This article is nothing but a 20-second story, to help explain to PHB's and noobs why they got an error message, or what sorta important stuff you're always busy keeping your org safe from.
If you're in IT at a scraping-by org: Maybe today's a good day to ditch 512-bit keys. And if you get push-back...gosh, here's a how-to article, showing how a "forged corporate signature stamp" can be made for only $8.
If you're trying to teach senior citizen how to avoid being scammed on the internet: You've got zero visibility or control, so you're stuck with "sometimes these can be forged, depending on technical details" generalities.