I'm afraid there's also a misunderstanding how the real world works. Cryptographic and real-world plausibility are two entirely different things.
People get blackmailed, shamed, hurt and even killed over mere rumors, speculations and suspicions. As long as people believe in something (because something merely look plausible), there's no need for a fancy crypto to prove some machine sent some email. I'd dare to say most people don't even understand what cryptography is and what digital signatures really are (who signs what and what exactly this means).
I'm yet to hear a story of, let's say, a brave dissident who got out of jail because of cryptographic plausible deniability property making their oppressors unable to prove authenticity of some leaked or intercepted correspondence.
Read up on the Hunter Biden emails. After a DKIM signature was verified, the perception of a large number of people (including right here on HN) went from "this cache of email is probably total fiction" to "they likely do have access to at least some of his emails".
They don’t have plausible evidence anyway. Gmail has had bugs before with SPF/DKIM and will have some again for sure.
Some google employees have direct and indirect access to signing keys or writing emails. Not many, and they have good controls, but still many people with the ability to sign messages.
Not to mention a Trojan infiltration or account takeover, of which thousands (if not millions) a day occur.
The DKIM evidence is, for legal purposes, a good hint but far from proof.
In the court of public opinion, the standard is not "100% proven beyond any reasonable doubt". Hence, blackmail can still be very effective if an accusation is highly plausible.
I am not sure why the DKIM for all emails were not released, or why this did not catch more media coverage by other news organizations I consider more reliable (like NYT).
Huh? No one (including yourself), have mentioned anything about "destruction of evidence" so far. If you care to enlighten me about how it's relevant I'm happy to listen.
By making the DKIM keys public, you are converting solid evidence of something that was said into something that was either really said, or someone else pretended that they said.
No, destruction of evidence involves things like making something impossible to analyze and evaluate. Publication of a key doesn't erase the original messages and does not make it impossible to look into their contents to try to establish authencity by external means. Causing ambiguity is not destruction of evidence.
That would be an act of submitting false evidence, where you actively make a false claim regarding who the sample belongs to.
Which is very distinctly different from a passive act of not maintaining evidence of the origin of every single thing. Keep in mind that no data is altered - the equivalent of all collected samples remaining intact.
It's still just as possible to collect email logs, their contents do not magically dissappear. They would have to be actively manipulated by the party which holds the copy that would be provided to the police (either reported to them or confiscated, etc). That same party could already decide to delete the emails or strip signatures and then alter them.
People get blackmailed, shamed, hurt and even killed over mere rumors, speculations and suspicions. As long as people believe in something (because something merely look plausible), there's no need for a fancy crypto to prove some machine sent some email. I'd dare to say most people don't even understand what cryptography is and what digital signatures really are (who signs what and what exactly this means).
I'm yet to hear a story of, let's say, a brave dissident who got out of jail because of cryptographic plausible deniability property making their oppressors unable to prove authenticity of some leaked or intercepted correspondence.