Re: [openpgp] Web Key Directory I-D -07

On Tue, 13 Nov 2018, Bart Butler wrote:

I was wondering what you think about saying something like:

The key MUST carry a
  User ID packet ([RFC4880]) with what the server considers the canonical form 
of the requested mail address.

So if I request from ProtonMail Bart(_dot_)Butler(_at_)protonmail(_dot_)com, I 
would get a key back with bartbutler(_at_)protonmail(_dot_)com, and the clients 
could then prompt on unrecognized types of mismatches if desired because they 
would know that the server is returning the canonical form of the address.


We went through this with OPENPGPKEY and SMIMEA. You will get the SMTP
people blocking your draft when you try to interpret (or like above,
even rewrite) addresses based on "common mail provider rewrites". Their
firm believe is only receiving SMTP servers can interpret email addresses.

Perhaps you want to take a look at the language used in those two
RFCs with respcet to mapping email addresses to DNS. Some of it
applies here too, and you will have some new ones with special
characters in URL's.

This took a year to resolve for RFC 7929 and RFC 8162. So I recommend
you look at previous discussion on this topic on the openpgp and dane
mailing lists.

Paul

-Bart

Sent from ProtonMail, encrypted email based in Switzerland.

‐‐‐‐‐‐‐ Original Message ‐‐‐‐‐‐‐
On Tuesday, November 13, 2018 6:02 AM, Werner Koch <wk(_at_)gnupg(_dot_)org> 
wrote:

Hi!

A new revision of the Web Key Directory I-D has been published:

https://www.ietf.org/id/draft-koch-openpgp-webkey-service-07.txt

Changes since -06 are:

-   Specify the advanced method with the openpgpkey sub-domain.

-   Specify the l=LOCAL-PART query parameter.

-   Require the provider to filter the key for publication.

-   Drop the use of DNS SRV records.

    See below for the gist of the change. GnuPG master implements the new
    advanced method. You may use my address for testing. For now the SRV
    method is still used as a fallback by GnuPG.

    Note that the domain name is now also part of the file name if the
    openpgpkey sub-domain is used. This should make it easier to server the
    directory for several domains from a single server. This sub-domain
    approach is similar to Mozilla's mail auto configuration [1].

    Shalom-Salam,

    Werner

    --8<---------------cut here---------------start------------->8---
    There are two variants on how to form the request URI: The advanced
    and the direct method. Implementations MUST first try the advanced
    method. Only if the required sub-domain does not exist, they SHOULD
    fall back to the direct method.

    The advanced method requires a sub-domain with the fixed name
    "openpgpkey" is created and queried. It constructs the URI from the
    concatenation of these items:

    o The scheme "https://";,

    o the domain-part,

    o the string "/.well-known/openpgpkey/",

    o the domain-part in lowercase,

    o the string "/hu/",

    o the above constructed 32 octet string,

    o the unchanged local-part as a parameter with name "l" using proper
    percent escaping.

    An example for such an advanced method URI to lookup the key for
    Joe(_dot_)Doe(_at_)Example(_dot_)ORG is:

    https://openpgpkey.example.org/.well-known/openpgpkey/
    example.org/hu/iy9q119eutrkn8s1mk4r39qejnbu3n5q?l=Joe.Doe

    (line has been wrapped for rendering purposes)

    The direct method requires no additional DNS entries and constructs
    the URI from the concatenation of these items:

    o The scheme "https://";,

    o the domain-part,

    o the string "/.well-known/openpgpkey/hu/",

    o the above constructed 32 octet string,

    o the unchanged local-part as a parameter with name "l" using proper
    percent escaping.

    Example for a direct method URI:

    https://example.org/.well-known/openpgpkey/
    hu/iy9q119eutrkn8s1mk4r39qejnbu3n5q?l=Joe.Doe

    (line has been wrapped for rendering purposes)

    [...]
    The benefit of the advanced method is its greater flexibility in
    setting up the Web Key Directory in environments where more than one
    mail domain is hosted. DNS SRV resource records, as used in earlier
    specifications of this protocol, posed a problem for implementations
    which have only limited access to DNS resolvers. The direct method
    is kept for backward compatibility and to allow providing a Web Key
    Directory even with without DNS change requirements.
    --8<---------------cut here---------------end--------------->8---

[1]https://developer.mozilla.org/en-US/docs/Mozilla/Thunderbird/Autoconfiguration

--

Die Gedanken sind frei. Ausnahmen regelt ein Bundesgesetz.


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