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rocqua • yesterday at 2:50 PM • 2 replies • view on HN

In practice we have Certificate Transparency Logs that let us check whether a CA has issued a certificate for a domain you control without you asking them to.

This really reduces how much we need to trust the CAs, because we can detect any untrustworthy actions after the fact. Now detecting after it happened is too late. But it does mean that mistakes or malicious actions are much more expensive to a CA. In practice this has really reduced the risk, especially to those whom aren't interesting enough to burn a valuable capacity on. Which is the vast majority of people. Though perhaps if you count TLS traffic weighted by importance that count is different.


Replies

zaptheimpaler • yesterday at 6:33 PM

I think someone explained that only browsers and maybe some applications check the CT logs in the first place. Most applications don't, so someone can impersonate any URL an application connects to and the attacker doesn't have to publish to a CT log.

krackers • yesterday at 8:44 PM

How would certificate transparency logs have helped here though? If the private key leaks and anyone can mint a valid certificate that gets accepted, those logs aren't going to reveal it.

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