Some organizations, including Mozilla, think domain validation is also a valid 
email validation use case.  This is especially important for enterprises.

 

But I agree with the rest.

 

-Tim

 

From: Ryan Sleevi [mailto:[email protected]] 
Sent: Thursday, May 24, 2018 10:18 AM
To: Tim Hollebeek <[email protected]>
Cc: Dimitris Zacharopoulos <[email protected]>; CA/Browser Forum Public 
Discussion List <[email protected]>; Moudrick M. Dadashov <[email protected]>; 
Brown, Wendy (10421) <[email protected]>
Subject: Re: [cabfpub] For Discussion: S/MIME Working Group Charter

 

Right, to be clear, I'm opposed to treating clientAuth with S/MIME.

 

I understand that, in some spaces, S/MIME identity is tied to legal identity. 
But S/MIME also has the potential of great value being tied to simply e-mail 
identity - or to organizational identity. If you will, this is the distinction 
between DV, IV, OV, and EV.

 

My view is that just like DV is the basis for all other forms of serverAuth 
certificates, e-mail validation is the core to S/MIME. Getting that correct 
prevents any future improvements - that is, you cannot build a legal identity 
of S/MIME without first establishing and validating the e-mail.

 

Thus, a good charter should start solely with S/MIME, and solely with e-mail 
validation.

 

If that is successful, as a Baseline, then folks can and should be free to 
safely explore building on that foundation for other forms - for example, if 
organizational validation is appropriate, or in the case of eIDAS, if 
individual validation.

 

clientAuth is orthogonal in this, in that it can have many different forms of 
asserted identities (such as a SAN of a dNSName or a SAN of an rfc822Name) or 
no technical identity. Its usage, like code-signing, is going to vary on the 
consumer - and thus general rules are NOT applicable, but instead is going to 
need to be evaluated for each and every application context. While eIDAS 
considers that notion, it's doing so on flawed technical grounds (an entirely 
separate issue), but I highlight it because the eIDAS notion of clientAuth is 
vastly different than, say, the XMPP notion of clientAuth, even though they use 
the same key policy.

 

The solution to all of these challenges is not to try to solve them all at 
once, it's to start and make sure there is a common base certificate profile, 
and a core understanding of the validation of the primary identifier 
appropriate for S/MIME (the email address), and then build more expressive, 
additive systems on top of that, if and as there is demonstrated need and 
consumption. Just because something "could" be done doesn't necessarily mean it 
should, and just because some PKIs (like eIDAS) introduce some ideas doesn't 
mean they're good - but without a firm footing, and without a charter to 
explicitly focus on solely that topic, not much progress can or will be made.

 

On Thu, May 24, 2018 at 8:57 AM, Tim Hollebeek <[email protected] 
<mailto:[email protected]> > wrote:

Yeah, I want something focused.  There are lots of different clientAuth use 
cases, not just individual identity.  clientAuth only looks like 
emailProtection if you’re limiting yourself to the use cases where there’s 
strong overlap.  Which makes the argument that they are similar essentially a 
tautology.  Remember, clientAuth can also be mutual authentication for web 
services.  That looks nothing like emailProtection.

 

So let’s get email on a firm footing first, and if the section of the 
clientAuth BRs for individuals is heavily based on the emailProtection BRs, 
that just saves us work in the future.

 

-Tim

 

From: Public [mailto:[email protected] 
<mailto:[email protected]> ] On Behalf Of Dimitris Zacharopoulos via 
Public
Sent: Thursday, May 24, 2018 1:05 AM
To: Moudrick M. Dadashov <[email protected] <mailto:[email protected]> >; Brown, Wendy 
(10421) <[email protected] <mailto:[email protected]> >; 
CA/Browser Forum Public Discussion List <[email protected] 
<mailto:[email protected]> >; Ryan Sleevi <[email protected] 
<mailto:[email protected]> >


Subject: Re: [cabfpub] For Discussion: S/MIME Working Group Charter

 


Moudrick, I don't think we are describing just use scenarios. This is about 
subject validation and as you are very well familiar, eIDAS is also setting 
requirements for how you validate natural persons and legal entities. Then, you 
can use this validated information for different trust services (authenticate, 
sign, encrypt, etc).

We already have identity validation requirements for the server certificate 
Working Group, described in DV/OV/EV Policies for certificates with 
id-kp-serverAuth EKU. Why shouldn't we include identity validation requirements 
for this new Working Group for certificates with id-kp-clientAuth and 
id-kp-emailProtection EKU? The overlap in subject validation requirements 
between these two cases is pretty obvious.

Even though I'd like the clientAuth to be included in the WG's initial charter, 
I understand Ryan's argument for gradually building a standard with minimum 
expectations at the beginning (thus limiting the scope for S/MIME only) and 
expand the scope later. 

So, until then, the clientAuth Certificates will remain kind-of "unregulated" 
by lacking a policy standard. I suppose we will have to live with that :)



Dimitris.

On 24/5/2018 2:34 πμ, Moudrick M. Dadashov wrote:

All three (clentAuth and S/MIME) use scenarios are essentially different.

Validation requirements for issuing signing/encryption certificates are mostly 
similar, clientAuth (as we understand it under eIDAS*) is different.

Thanks,
M.D.  

* Article 3
(5) ‘authentication’ means an electronic process that enables the electronic 
identification of a natural or legal person, or the origin and integrity of 
data in electronic form to be confirmed.

(1) ‘electronic identification’ means the process of using person 
identification data in electronic form uniquely representing either a natural 
or legal person, or a natural person representing a legal person.

(2) ‘electronic identification means’ means a material and/or immaterial unit 
containing person identification data and which is used for authentication for 
an online service.

 

On 5/24/2018 12:16 AM, Brown, Wendy (10421) via Public wrote:

I second the opinion that  clientAuth and S/Mime are likely to have a great 
overlap in validation requirements at least when issuing to persons and PKIs 
may want to issue both types of certs from the same CA if they are for the same 
validated individual..

 

From: Public [mailto:[email protected]] On Behalf Of Ryan Sleevi via 
Public
Sent: Friday, May 18, 2018 9:18 AM
To: Dimitris Zacharopoulos  <mailto:[email protected]> <[email protected]>; 
CA/Browser Forum Public Discussion List  <mailto:[email protected]> 
<[email protected]>
Subject: Re: [cabfpub] For Discussion: S/MIME Working Group Charter

 

 

 

On Fri, May 18, 2018 at 12:57 AM, Dimitris Zacharopoulos via Public 
<[email protected] <mailto:[email protected]> > wrote:

 

On 18/5/2018 2:51 πμ, Ryan Sleevi via Public wrote:

I don't think it's a cross-EKU situation, though, but I'm glad we're in 
agreement. 

 

An email server certificate is an id-kp-serverAuth EKU. That's already covered 
by another WG


I sincerely hope that id-kp-clientAuth EKU will also be covered by this WG 
since there will be common validation requirements for Subject information, as 
with S/MIME. It seems too much overhead to spawn an entirely different WG to 
deal just with clientAuth.

If people agree, how about using the name "Client and S/MIME Certificate WG" 
which seems aligned with the "Server Certificate WG"?

 

As I've mentioned several times, it would be good to actually focus on a 
constrained, defined problem, before you proverbially try to boil the ocean.

 

It is not obvious that there will be common validation requirements, because 
the id-kp-clientAuth situation has a vast dimension of possible uses and 
spectrum. It's not actually reflective of the deployed reality that the 
validation requirements are the same. It also is based on an entirely separate 
notion of identity.

 

So no, I don't agree, because they really are substantially different in 
deployed reality - and an S/MIME WG is, in itself, a sizable undertaking just 
to get S/MIME BRs, due to the broad spectrum of client capabilities and CA 
past-practices - and the lifetime of extant certificates that presents unique 
challenges to defining a sensible and realistic profile.

 

A good charter - one that leads to productive engagement from a broad set of 
participants while actually delivering meaningful improvements - is one that 
keeps itself narrowly focused on the task at hand, produces results, and then 
looks to recharter based on the things you knew were out there, but agreed not 
to discuss until you actually completed the work. That allows you to keep 
momentum, focus, and participation. Just look at the challenges each of our 
(legacy) WG has faced with a broad remit, in that the set of topics has made it 
difficult both to engage participation of the broader Forum and to actually 
make forward progress, because it's constantly having to deal with 'all these 
things' or trying to do 'all these things'.

 

When we see narrowly focused ballots and efforts that try to solve a specific 
set of problems, then we make progress. The validation WG's effort at 3.2.2.4 
is a prime example of that - a prolonged effort that directly benefited from 
being focused on that problem, and ruling some things (like 3.2.2.5) out of 
scope of the discussion in order to make progress on the narrow set.

 

The same too is in the charter. Let's not try to encompass pet marketing 
projects (EV for S/MIME), "things we might need but we don't know why" (network 
security), or "things that are kinda related, but only in some domains" 
(id-kp-clientAuth). Let's focus on the problem at hand - S/MIME authentication 
- keeping the WG scoped narrowly and on task, and deliver something that can 
help users have faith in the Web PKI to deliver tangible benefits in that 
space, rather than the reality we have today.

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