Comment by vbezhenar
2 days ago
Can you revoke certificate for a specific device using privacy schemes?
Like imagine that someone managed to extract key from the specific device and distributed that key in a software implementation to fake attestation. Now Google needs to revoke that particular key to disallow its usage. This is obvious requirement.
Yes, with blind signatures you still have a central authority which voluntarily 'launders' tokens for you. When you present it your certificate and ask it to give you a blind signature it can reject the certificate.
However if someone extracts a key and keeps it private, and instead gives out unblinded tokens there is nothing you can do other than rate limit - realistically, an adversary is going to trial different rates anyway to figure out which don't make them an outlier.
Especially if the device in question is linked to an enemy of the state and the people.