An email exchange has two users: one is the sender, the other the receiver. As the receiver, having proof that I received an email from you is potentially a fea

An email exchange has two users: one is the sender, the other the receiver. As the receiver, having proof that I received an email from you is potentially a feature, not a problem. More generally, authenticated communication has a long history of being considered a useful thing for society. Physical mail includes delivery confirmations where the receiver must sign for the receipt, proving to anyone that they did receive the letter. People would often add hard-to-forge personal seals to letters in even older days, that could prove to anyone that they were the ones who sent that document. And even common letters were usually signed rather, even when typewritten, again making it hard to later repudiate. While I absolutely see the value in making it possible to securely send repudiatable email in some specific circumstances, I think having non-repudiatable email as the default is a net benefit to society, and has been the de facto standard for at least a few hundred years before email ever came along.