It's hard to explain partly because when you explain this thing we've done with TLS and PKI, it sounds a little insane.

> "We set up a system where every government and a bunch of random banks and IT companies in the world holds the secret codes to everyone's encryption. Then we make them pinky swear not to abuse it, with stern talkings to if they do. And now it's all on fire, because one of them was irresponsible!"

You can know the intractability of the problem that PKI is solving, and the (worse) alternatives that have been tried, but that doesn't make this system not-insane to a normal person, and its at least a little bit the fault of the collective "us".

And it's not like it is an impossible problem; we rely on TOFU for SSH, we have remotely-attestable TPMs everywhere, ZKPPs / PAKEs exist, session keys and federation protocols are widespread. Somewhere in the set of "possible solutions" are options that don't sound unhinged when you explain how we got to this eMuhdra situation.

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brabel 4 hours ago | parent [-]

I believe you misunderstood how it works. A parent certificate cannot be used to decrypt information encrypted by a child certificate… the CA issuer just signs your child certificate, it doesn’t have access to your private key.

Then, everyone who trusts the CA will trust your certificate by checking it is signed by the CA who should have done the checks to ensure your certificate contains truthful data.

So your layman description of “they have secret codes to everyone’s encryption” is completely wrong.

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kbolino 4 hours ago | parent | next [-]

Certificate keys aren't used for encryption anymore anyway.

A modern TLS connection uses an ephemeral key-exchange protocol where both parties opaquely agree to a one-time-use random encryption key that is not knowable to any other party, not even someone who can gain access to either party's private key. This is called Forward Secrecy (originally and sometimes still known as Perfect Forward Secrecy or PFS, but the use of the word "perfect" in any cryptographic context is akin to naming a ship "Unsinkable").

	▲	brabel an hour ago \| parent [-]
		Right, thanks for correcting me. This stuff is not so simple to get right.

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FromOmelas 4 hours ago | parent | prev [-]

They have the secret codes to MITM (intercept, inspect, alter and forge) any communication if they manage to place themselves between you and a party you trust.

	▲	brabel an hour ago \| parent [-]
		Ok, but the analogy was wrong anyway. > random banks and IT companies in the world holds the secret codes to everyone's encryption. That's not true at all. What they do have is the power to MITM connections IF they first spook DNS or insert themselves into a proxy accepted by the server somehow. So, if you want to be honest, the original sentence becomes: > random banks and IT companies in the world holds secret codes that are trusted by everyone to sign information that is used to establish trusted communications. If they wanted to, they could try to tamper with people's network connections and, if successful somehow, pretend to be anyone else that had used their secret codes to sign their information. Quite a big difference, no?