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> So if you hit FooCo's corporate website and get one certificate, and some other guy hits the same website and they get another, it's likely something fishy is
by cesarb 12y ago
> So if you hit FooCo's corporate website and get one certificate, and some other guy hits the same website and they get another, it's likely something fishy is happening. Replace this model of two people with a few million, and you have a pretty decent verification system happening.
In this model, the trust root is the verification system which compares your "hit" with other people's "hits". If an attacker can pretend to be the verification system and tell you "everything's fine", the system won't work. Also, it's centralized: the verification system itself becomes the central component.
- vidarh 12y agoSuch a verification system does not need to be centralized. It can be a public, signed log that can be verified with other parties.
- yuliyp 12y agoWhat's to stop an attacker from poisoning such a system: pretend to be a thousand different people all saying "Yep, the cert with signature 0xBADBADBAD was what I saw"? How does someone rotate certs without breaking all their existing clients?
- vidarh 12y agoNothing stops an attacker from pretending to be a thousand different people, but there are a couple of obvious improvements you can make: - Don't just check the certs you want to verify, but also check others, and publish your findings. - Check with multiple alternative systems, so that the chance of - Allow users to assign trust to third party monitors that checks the logs. Rotating certs is not really a different problem than issuing it in the first place - it just requires you to not trust a cert indefinitely.