W3C home > Mailing lists > Public > public-credentials@w3.org > March 2015

Re: Leveraging DNS and email addresses

From: Melvin Carvalho <melvincarvalho@gmail.com>
Date: Mon, 23 Mar 2015 15:36:44 +0100
Message-ID: <CAKaEYhLg9FRv6xvOUjSKuBGF8bU3gZn4jDSv0HHw1JohAxkyew@mail.gmail.com>
To: Adrian Hope-Bailie <adrian@hopebailie.com>
Cc: W3C Credentials Community Group <public-credentials@w3.org>
On 16 March 2015 at 09:02, Adrian Hope-Bailie <adrian@hopebailie.com> wrote:

> I have been thinking lately about the challenge of keying an identity in a
> way that:
>    - Is easy to transfer and remember (even for humans)
>    - Can be normalised in a standard way and used as part of a
>    standardised discovery process by a client to discover the Identity
>    Provider (IdP) for that identity
> *ASIDE: It's worth mentioning that while we strive for a fully
> decentralised identity system this will likely be a federated set of IdPs
> and for a client to traverse this web they need a starting point or primary
> IdP for an identity. When I talk about the IdP for an identity I am not
> implying there will be only 1 but that that the key/label for the identity
> should allow a client to resolve/discover this primary IdP and then from
> there discover further identity claims as required.*
> To my mind the obvious solution is to use the email address format as this
> is already a well-known standard which user's understand.
> It seems to me that the only argument against an email address format is
> that the domain part is often not under the control of the identity owner.
> I don't see that is a good enough reason to force users to try and change
> their thinking and use URIs as their identifiers.
> I don't have statistics to back this up (perhaps somebody does) but I
> consider the relative obscurity of OpenID as a login option as evidence
> that this is a bad idea.
> So how do we help the user that has an email address @gmail.com or @
> hotmail.com or @yahoo.com but wishes to host their identity themselves or
> at a different IdP?
> First, we define a mechanism or standard algorithm/protocol for
> translating their email address into a service discovery process that may
> start with their home domain but ultimately result in the client accessing
> the identity somewhere else. Then we pressure the large email providers to
> abide by this standard. I acknowledge that this may be difficult but I
> would say it is not impossible.
> I imagine the user experience being something like the following:
>    1. I log in to my account with this email provider, go to my account
>    settings and prpvode the URL of my IdP.
>    2. When I use my identity online the client executes the service
>    discovery protocol as defined, contacts my email provider and is given the
>    URL I have configured as part of this process.
>    3. The client negotiates with my IdP of choice to get my identity
>    information.
> If we have designed the protocol correctly (very close to what is already
> in place today) my email provider only knows who my IdP is but nothing more
> about the identity I have defined their unless I choose to share it.
> Where a user has a primary email address with a provider who is not
> following the standard the user has two choices:
>    1. Change email providers
>    2. Use an identity that is different from their primary email address.
> Option 2 can be easily facilitated by any IdP who wishes to play in this
> space. In conjunction with offering an IdP service they could also allow
> their identity key (email address) to be used as an email address by the
> subscriber but simply forward all emails to that address on to the primary
> email address of the subscriber.
> I think the Discovery protocol of OpenID Connect (
> http://openid.net/specs/openid-connect-discovery-1_0.html) is a good
> reference of how an email address could be used to discover the user's IdP
> however I'd be more in favour of leveraging the DNS service discovery
> protocol (RFC 6763 - http://www.dns-sd.org/).
> Is there a compelling case for using a URI as an identity key as opposed
> to the familar form of an email address?

Let's not go down this path in discussion.  Email is confusing because it's
overloaded to do different things:

1. A memorable identifier
2. A global primary key
3. A message delivery service

This stalls meaningful discussion in the standards world, and we end up
with failed projects such as persona.

Just using web axioms an email address as an identifier (2) is already a
URI by prefixing mailto: (something that most centralized and many
'decentralized' systems forget to do)

In the linked data world we prefer http uris.

This is an endless perma debate that gets in the way of standards.  Let's
not go there!

> Adrian
Received on Monday, 23 March 2015 14:37:14 UTC

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