Re: Email is absolutely broken...
"Just how are you going to know that the person purporting to be Alice is really Alice? That's why key signing parties were a thing back in the '90's. Without a sort of central registery for certificates, you aren't solving the problem of absolutely knowing that it's not really Eve."
Your mention of Alice and Eve had me trying to remember the other characters used as examples in security scenarios. I managed Bob and Mallory but didn't realise the list was so long:
For commentards who don't know who these folks are, that page starts with:
Alice and Bob are fictional characters commonly used as placeholder names in cryptology, as well as science and engineering literature. The Alice and Bob characters were invented by Ron Rivest, Adi Shamir, and Leonard Adleman in their 1978 paper "A method for obtaining digital signatures and public-key cryptosystems." Subsequently, they have become common archetypes in many scientific and engineering fields, such as quantum cryptography, game theory and physics. As the use of Alice and Bob became more popular, additional characters were added, each with a particular meaning.