Re: [Privacy-pass] Draft on key consistency and discovery

Eli-Shaoul Khedouri <eli@intuitionmachines.com> Fri, 26 February 2021 21:19 UTC

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From: Eli-Shaoul Khedouri <eli@intuitionmachines.com>
Date: Fri, 26 Feb 2021 13:19:29 -0800
Message-ID: <CA+AE54ch3AvS=h71RemZXQcdd4xU2BFJn1z4SCbZkqEpS9skAw@mail.gmail.com>
To: Ben Schwartz <bemasc=40google.com@dmarc.ietf.org>
Cc: Matthew Finkel <sysrqb@torproject.org>, Christopher Wood <caw@heapingbits.net>, privacy-pass@ietf.org
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Archived-At: <https://mailarchive.ietf.org/arch/msg/privacy-pass/zpZl4msXF5ldJhKis9ccpXCyQOk>
Subject: Re: [Privacy-pass] Draft on key consistency and discovery
Precedence: list

On Fri, Feb 26, 2021 at 12:28 PM Ben Schwartz <bemasc=
40google.com@dmarc.ietf.org> wrote:

>
>
> On Thu, Feb 25, 2021 at 6:40 PM Matthew Finkel <sysrqb@torproject.org>
> wrote:
>
>> > For Privacy Pass, at least, there is potentially a presumption that the
>> > user has access to the network in a way that hides their identity and
>> does
>> > not collude with the target.  This might mean that the user's DNS
>> resolver
>> > is presumed to be trusted.  In that model, the resolver could act like a
>> > trusted proxy (Section 4.2).
>>
>> Yes, but that could be misleading. "One DNS resolver" does not
>> necessarily translate into one DNS cache, especially not a global DNS
>> cache, so the global consistency properties of DNS are a bit fuzzy.
>>
>
> Yes.  On the other hand, an adversary can probably identify which resolver
> cache instance you're hitting by putting a different IP in each one, so
> privacy beyond that level may be an illusion.
>

This can be detected and mitigated by the client with TACK
<http://tack.io/draft.html>-style pinning pools, but seems a bit out of
scope for the core protocol.

[Privacy-pass] Draft on key consistency and disco… Christopher Wood
Re: [Privacy-pass] Draft on key consistency and d… Ben Schwartz
Re: [Privacy-pass] Draft on key consistency and d… Matthew Finkel
Re: [Privacy-pass] Draft on key consistency and d… Ben Schwartz
Re: [Privacy-pass] Draft on key consistency and d… Eli-Shaoul Khedouri
Re: [Privacy-pass] Draft on key consistency and d… Ben Schwartz