Re: [dns-privacy] Adaptive DNS Privacy and Oblivious DoH

[Tommy Pauly <[e-mail]>]

Hello DNS Privacy,

We've posted new versions of our drafts on discovering designated DoH servers, and Oblivious DoH:

https://tools.ietf.org/html/draft-pauly-dprive-adaptive-dns-privacy-01
https://tools.ietf.org/html/draft-pauly-dprive-oblivious-doh-01

We got a lot of good input via email and on the GitHub. Some of the main changes in these versions are:

- Don't reserve a SVCB SvcParamKey yet (https://github.com/tfpauly/draft-pauly-adaptive-dns-privacy/issues/60)
- Change the Oblivious DoH proxying mechanism to specify the target in the HTTP path query (https://github.com/tfpauly/draft-pauly-adaptive-dns-privacy/issues/64)
- Derive a nonce from client random values (https://github.com/tfpauly/draft-pauly-adaptive-dns-privacy/pull/74)

Open issues that are tagged with "DISCUSS" can be found here. Please chime in if you have opinions!
https://github.com/tfpauly/draft-pauly-adaptive-dns-privacy/labels/discuss

Thanks,
Tommy




Name:		draft-pauly-dprive-adaptive-dns-privacy
Revision:	01
Title:		Adaptive DNS: Improving Privacy of Name Resolution
Document date:	2019-11-01
Group:		Individual Submission
Pages:		25
URL:            https://www.ietf.org/internet-drafts/draft-pauly-dprive-adaptive-dns-privacy-01.txt
Status:         https://datatracker.ietf.org/doc/draft-pauly-dprive-adaptive-dns-privacy/
Htmlized:       https://tools.ietf.org/html/draft-pauly-dprive-adaptive-dns-privacy-01
Htmlized:       https://datatracker.ietf.org/doc/html/draft-pauly-dprive-adaptive-dns-privacy
Diff:           https://www.ietf.org/rfcdiff?url2=draft-pauly-dprive-adaptive-dns-privacy-01

Abstract:
  This document defines an architecture that allows clients to
  dynamically discover designated resolvers that offer encrypted DNS
  services, and use them in an adaptive way that improves privacy while
  co-existing with locally provisioned resolvers.  These resolvers can
  be used directly when looking up names for which they are designated.
  These resolvers also provide the ability to proxy encrypted queries,
  thus hiding the identity of the client requesting resolution.


Name:		draft-pauly-dprive-oblivious-doh
Revision:	01
Title:		Oblivious DNS Over HTTPS
Document date:	2019-11-01
Group:		Individual Submission
Pages:		14
URL:            https://www.ietf.org/internet-drafts/draft-pauly-dprive-oblivious-doh-01.txt
Status:         https://datatracker.ietf.org/doc/draft-pauly-dprive-oblivious-doh/
Htmlized:       https://tools.ietf.org/html/draft-pauly-dprive-oblivious-doh-01
Htmlized:       https://datatracker.ietf.org/doc/html/draft-pauly-dprive-oblivious-doh
Diff:           https://www.ietf.org/rfcdiff?url2=draft-pauly-dprive-oblivious-doh-01

Abstract:
  This document describes an extension to DNS Over HTTPS (DoH) that
  allows hiding client IP addresses via proxying encrypted DNS
  transactions.  This improves privacy of DNS operations by not
  allowing any one server entity to be aware of both the client IP
  address and the content of DNS queries and answers.

> On Oct 4, 2019, at 10:34 AM, Tommy Pauly <tpauly=[e-mail]> wrote:
> 
> Hello DNS Privacy,
> 
> We’ve published a set of new drafts that define what we’re calling “Adaptive DNS Privacy”. This is an approach to using technologies like DoH to improve privacy of name resolution without breaking the functionality provided by local network resolvers. It also does not require placing trust in one or more fixed resolvers, but instead allows server deployments to dynamically indicate which resolvers are designated for their zones.
> 
> From the perspective of an operating system vendor (for myself, iOS and macOS), the goal is to use this approach to DNS privacy in the system stub resolver such that it can be safely and automatically used by all applications.
> 
> The first draft is “Adaptive DNS: Improving Privacy of Name Resolution”.
> https://tools.ietf.org/html/draft-pauly-dprive-adaptive-dns-privacy <https://tools.ietf.org/html/draft-pauly-dprive-adaptive-dns-privacy>
> 
> This covers the overall architecture for both clients and server deployments. This includes:
> 
> 	• A mechanism for clients to discover DoH resolvers that are “designated” for certain names or zones, using a DNSSEC-signed SVCB record (https://tools.ietf.org/html/draft-nygren-dnsop-svcb-httpssvc <https://tools.ietf.org/html/draft-nygren-dnsop-svcb-httpssvc>).
> 	• An algorithm for clients to select which resolver to use for a given name based on precedence (defining how VPNs, local network resolvers, designated cloud-based resolvers, and Oblivious DoH lookups coexist).
> 	• A mechanism for local networks to advertise their rules and capabilities using a provisioning domain (https://tools.ietf.org/html/draft-ietf-intarea-provisioning-domains <https://tools.ietf.org/html/draft-ietf-intarea-provisioning-domains>); this allows the advertisement of a locally-designated DoH server, a list of names or zones over which the local network claims authority, and an indication of filtering requirements.
> 
> The second draft is “Oblivious DNS Over HTTPS”, which we refer to as ODoH. 
> https://tools.ietf.org/html/draft-pauly-dprive-oblivious-doh <https://tools.ietf.org/html/draft-pauly-dprive-oblivious-doh>
> 
> Inspired by Oblivious DNS (https://tools.ietf.org/html/draft-annee-dprive-oblivious-dns <https://tools.ietf.org/html/draft-annee-dprive-oblivious-dns>), this draft adds an extension to DoH for encrypting queries such that a resolver cannot know both the client’s IP address and the content of the DNS query. In contrast to Oblivious DNS, ODoH uses HTTP proxying to unlink query sources and destinations. (ODoH also uses HPKE (https://tools.ietf.org/html/draft-irtf-cfrg-hpke) for query public key encryption.)
> 
> Please take a read through the documents and provide feedback. We’re eager to iterate on these goals with the community.
> 
> You can also provide feedback and input on the GitHub repo: https://github.com/tfpauly/draft-pauly-adaptive-dns-privacy.
> 
> If you are interested in working on implementing any of these protocols, please reach out for interop testing, etc. 
> 
> Best,
> Tommy, Chris, Eric, and Patrick
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