The Internet was concieved decades ago. In hindsight, many bad design choices were made. Given what was known at the time it's still blows my mind how well it has aged. There are some

Hypothetical scenario: what design choices would we change security wise if we had the opportunity to redesign the Internet from scratch today? Or to tackle the problem the other way around: what are the bad design choices for Internet security that we are stuck with today, unfixible without starting over?