This is a neat design, but, does this not just shift the issue of trust as to whether the proxy and the target are colluding:
> However, each of these guarantees relies on one fundamental property — that the proxy and the target servers do not collude. So long as there is no collusion, an attacker succeeds only if both the proxy and target are compromised.
I'm not sure how an end user would be expected to assess this any more than they could ascertain whether any particular DoH/DoT provider is as trustworthy as they claim.
Exactly what I was thinking. It doesn't even really help to run your own proxy on a server somewhere, because although the target wouldn't know for sure what the client's IP address is, queries from just one IP are likely to be easily correlated (statistically or otherwise).
So you convince some neighbors to use your proxy... As the number of clients grows, so does the uncertainty that the person running the proxy isn't colluding with the target, so you're back to the same trust issue that you were trying to solve in the first place.
Well, this could probably encourage the creation of privacy-oriented proxys (they just have to forward queries, so it should be relatively inexpensive compared to a full DNS server). What is the likehood of someone getting logs from Cloudflare (who promises it does not keep logs, but let's assume it does) and at the same time hacks into some random privay-oriented organization?
Of course, one might imagine a State actor using all their resources to do just that. But this would be a very complex attack. At least, it would stop all kind of ad tracking.
The worst part of this proposal is that it will further centralize the DNS infrastructure.
> However, each of these guarantees relies on one fundamental property — that the proxy and the target servers do not collude. So long as there is no collusion, an attacker succeeds only if both the proxy and target are compromised.
I'm not sure how an end user would be expected to assess this any more than they could ascertain whether any particular DoH/DoT provider is as trustworthy as they claim.