Alternate designs have lots of issues. The most prominent alternative, PGP's web-of-trust, quietly failed in the market (seriously, even most of my cryptographe

Alternate designs have lots of issues. The most prominent alternative, PGP's web-of-trust, quietly failed in the market (seriously, even most of my cryptographer colleagues don't have (up-to-date) keys). There is some talk of using DNS to authenticate servers - just stuff a public key into DNSSEC authenticated records - but it'll be a while before that is actually ready. And someone will still have the key to the DNS root, and all of this stuff only works if DNS fails closed (i.e. breaks if there are no signatures), which won't happen anytime soon.