Security by design. Old internet protocols have been built with the mind of "we're all friends here, we won't make each other's life hard, right?" Well, that di

Security by design. Old internet protocols have been built with the mind of "we're all friends here, we won't make each other's life hard, right?" Well, that didn't exactly work out. That's why we have spam, DNS hijacking, DDoS, botnets, etc. If some prophet could have convinced people that built early internet that security is as much of a concern as, say, availability and fault-tolerance - I am sure we would have much less of these problems.