2 ms·
Thinking about this further: it looks to me like we can fully prevent proxy attacks if we assume secure hardware handling the cryptography on the client side, a
by DennisP 4mo ago
Thinking about this further: it looks to me like we can fully prevent proxy attacks if we assume secure hardware handling the cryptography on the client side, and send an encrypted sessionid to the client after verification.
The reason is that:
- We send a random number from the server at the beginning which is associated with the session, so a proxy can't just replay the encrypted proof.
- We pass the server key into the proof, so a MITM attack would give the wrong server key to the client, and the real server wouldn't be able to verify the proof.
Then with each request the secure hardware can provide encrypt(sessionid, nonce).
- spwa4 4mo agoThis would not be anonymous and would allow website owners to uniquely identify the hardware used to authenticate. So, once again: you can have a secure system XOR you can have anonimity.
- DennisP 4mo agoWell it would be anonymous because the client public key is randomly generated every time, and the zk proof doesn't include the identifier.
- spwa4 4mo agoIf the public key signature of that random public key can't be uniquely identified as belonging to a particular device (allowing for a device to be revocated), then all it takes is 1 compromised phone to make the system insecure ... (to say nothing of the fact that because of EU regulations the secure element is not app accessible on either apple or android. So you won't just be dependent on Google/Apple, you'll be using their APIs (which report every authentication to them) every single time an ID is needed) If you can identify the device even just with a unique identifier, it's not anonymous.
- DennisP 4mo agoI already described in detail how to do revocations despite the website not being able to identify the device. The whole point of zero knowledge is that you can prove you have possession of information with particular properties, without having to actually reveal the information. I explained how to use this in my first reply to you. You're just repeating your claim without bothering to understand the first thing about the technology I'm talking about. Age verification itself is a change to regulations. Obviously to make a private system, our regulations would have to change in a way that allows that, instead of in a way that destroys all privacy as they're attempting now.
- spwa4 3mo agoAnd you again switch to dropping the other requirement. You would never be able to find the credentials to revoke to restore security if there is true anonymity.
- DennisP 3mo agoThe only requirement I dropped is absolute perfect security, which no system will have and certainly not the nonsense "show your ID to the camera" stuff they're actually using. I showed how to eliminate proxies, and without that, the only hole is the credentials themselves getting passed around. If that happens at a small scale between people who know each other, it's a minor problem. If a credential gets posted online and widely shared, it's easy to notice and revoke it.
- spwa4 3mo agoNo you go in a circle. My claim is: the system can be secure XOR the system can be anonymous. And you go in circles. One post, you drop anonymity, I point out that leads to security problem, next post you drop security and ... you get back anonymity, I point that out and, guess where we go from there? I mean your list of replies is becoming an ever stronger argument for what you're denying.