In a recent essay, Bruce Schneier tasks the engineering community with redesigning and rebuilding the vulnerable parts of the Internet's backbone.
We need to figure out how to re-engineer the Internet to prevent this kind of wholesale spying. We need new techniques to prevent communications intermediaries from leaking private information.
In my mind, one of the most glaringly vulnerable parts of the Internet's security infrastructure is the certificate authorities. They're big, private companies, vulnerable to legal and extralegal attacks from governments and hackers alike. They nevertheless hold the keys (no pun intended) to the kingdom, cryptographically speaking.
Are these kinds of central trust authorities the sine qua non of a practical public-key infrastructure? If so, why?
If not, what alternatives exist? What would it take to use one of these alternatives in a new, less vulnerable public-key infrastructure? What is the cryptography community's role in this discussion?