Subject: Re: QC DN "qualities". Was: I-D ACTION:draft-ietf-pkix-qc-04.txt

From: "Anders Rundgren" <[email-masked]>
Date: Fri, 14 Jul 2000 15:57:02 +0200

Stefan,

>The requirement that 2 physical persons never can have the same DN, is to 
>go beyond a technical uniqueness  concept.
>
>I tried to have a "functional" requirement in there (the unmistakable 
>identity requirement), but got the whole European ETSI group against me 

You did? Could I maybe have the e-mail to one of those ETSI-morons?

>saying that such requirement, regardless how desirable it might be, can't 
>be 100% globally accomplished in a practical world (in all countries).

I assume that the ETSI group means that CA/RAs in some countires can't keep track
of the people they certify.   How useful are legally binding signatures under such circumstances?
Because if a CA *can* keep track of people, the technical part is a no-issue as they
can always add a disambiguiting element such as serialNumber.  Note: w.o. turning
to social security numbers or other politically sensitive actions...

>Last IETF/PKIX meeting decided that Denis "Permanent Identifier" topic 
>should be advanced in a separate work item to be merged later, if 
>successful, with RFC 2459 or the QC profile.

This is an entirely other issue as Permant Identifiers is a step up from requiring DNs to not be reissued
as Permanent identifiers allows changing DNs while still linking to the same identity.

Anders

---

From: Paul Halliden <[email-masked]>
Date: Fri, 14 Jul 2000 14:35:02 +0100

Anders

<snip>
>Could I maybe have the e-mail to one of those ETSI-morons?
>
Not very professional language  :-(

>I assume that the ETSI group means that CA/RAs in some 
>countries can't keep track of the people they certify. 
>  
No! In law and administration of some countries, there is no concept of
"unmistakable identity". I was taught that this is deliberate policy in
protection of civil liberties.  The principle is that, if an administration
has control over an unmistakable identity - they also have the undesirable
ability to deny such an identity and therefore create non-people. Whether,
in these days the threat is real or not, does not matter.  The fact is that
the concept of unmistakable identity does not exist and mandating it in a
technical specification will not change that.  There is, of course, nothing
to stop those countries that do have the concept, making use of it.

<snip>
>How useful are legally binding signatures under such circumstances?
>
We have managed to have legally effective signatures for over 1000 years
under such circumstances - so quite useful I guess.

Regards
Paul Halliden

---

From: "Anders Rundgren" <[email-masked]>
Date: Fri, 14 Jul 2000 19:13:26 +0200

Paul K (not to be confused with Paul H :-)),

<snip>

> Anders> Pardon me but I don't get it.  If my statement about ETSI is
> Anders> correct the whole idea of certification is flawed but you say
> Anders> my statement is incorrect.  IMO that means that the
> Anders> adminstration DO know their subjects which you claim they
> Anders> don't for liberty reasons.
>
>Actually, no.  For one thing, in the USA there are no "subjects".  But
>even if you mean "citizens", the administration doesn't know them
>all. There are plenty of ways to become known to the various
>administrations (get a driver's license, register to vote, etc.) but
>those various registries aren't necessarily tied together, the names
>used aren't necessarily the same, and you aren't under legal
>compulsion to do any of these things if you can put up with the
>inconvenience of not doing so.

And for the very same reasons there will probably never be a single national US CA issuing QCs.

But there will be local, commercial, and private US QC CAs who will have RAs that in some way
make sure that the same identity (DN) is not given to two subjects/citizens!

A solution to the obvious non-consensus situation is that you make different QC policy IDs that
sets the "quality level" and then let the market decide and enable RP software to be automated.

Anders

---

From: [email-masked]
Date: Fri, 14 Jul 2000 12:34:54 -0400

Is it not a technical requirement that the combination of the subject
name and the subject alternate name (at a minimum) be different if the
individuals are different?  In fact, X.509v3 section 11.2 has a note which
states "a certification authority shall not issue certificates for two
users with the same name", and this note is reproduced in X.509v4 section
7.2.  I don't think that QC's have a lesser requirement along these lines
than ordinary PKC's.
     My own view is that this requirement should be interpreted as
including a Subject Alternate Name extension as part of the name, at least
when the extension is critical.  However, this point is open to debate.

          Tom Gindin

Stefan Santesson <[email-masked]> on 07/14/2000 08:17:09 AM

To:   Anders Rundgren <[email-masked]>, IETF-PXIX
      <[email-masked]>
cc:
Subject:  Re: QC DN "qualities". Was: I-D ACTION:draft-ietf-pkix-qc-04.txt

Anders,

The "technical profile" specify what attributes to use, what type of
information to put in them and also states technical uniqueness
requirements. The technical uniqueness requirement from RFC 2459 stands.

We must recognize that the real world have a context factor that we never
can capture in a technical standard.

That work has first to prove that you can make a useful "technical"
definition of the uniquness requirement in "permanent identifiers", which
still remains to be done.

/Stefan

At 12:49 2000-07-14 +0200, you wrote:
><snip>
>
>Denis wrote:
>
> >> >In order to make the text unambiguous it is important to say that:
"The
> >> DN MUST be unique  for
> >> >each subject entity certified by the one CA as defined by the issuer
> >> name field during the whole
> >> >life time of the CA, i.e. two different living human beings cannot
have
> >> the same DN."
>
>
>Stefan responded:
>
> >I agree that this is a good practice. There are however limitations on
how
> >far you can make requirements on practice in a technical profile.
>
>
>QC is not 2459.  QC is supposed to support legal systems and MARKET needs.
>For a CA that adhere to the word "Qualified" this is not a hard thing to
>require.
>It is anyway obliged to keep track of its subjects.  So what is the
>problem????
>
>Without restrictions on DNs QC is IMO redundant.  With the restriction
>requested by Denis
>you got a useful product (sorry - "techical profile" if that feels
better).
>
>May I kindly ask potential issuers of QCs to either stand by this
statement or
>not?

---

From: Paul Halliden <[email-masked]>
Date: Fri, 14 Jul 2000 18:02:29 +0100

Tom
In fact, X.509v3 section 11.2 has a note which
>users with the same name", 
>
This is not the point at dispute. The QC text used to have an additional
requirement that a QC contained "an unmistakable identity ... which ...
relates to a specific entity."  It also contained the concept of "a
corresponding officially registered identity".  

The contentious point is that this requirement has been dropped.  the reason
is that, in some jurisdictions there is simply no support for the
"unmistakable" concept.  Thus the subject name can be unique within the CA's
name space.  There is still a potential for mistaking that identity with
someone else not registered by the CA.  There is also ambiguity as to
whether two different names in the same space refer to the same physical
person - especially over time when a lot of the evidence supporting identity
(address, appearance, etc) can change.  In some countries, you can address
this issue by, e.g. referring to some unique national identity number.  In
others, such as the UK and USA there is no such thing.

Regards
Paul Halliden

---

From: [email-masked]
Date: Fri, 14 Jul 2000 13:44:10 -0400

Responses below.  I think you might want to read
draft-ietf-pkix-pi-00.txt.  I do understand, and I hope that most of the WG
does as well, that there is principled political resistance in the USA and
several other countries to the existence of a national ID number, and that
no such number is likely to come into existence in those countries.  The PI
draft is intended to give RP's what they need to identify or distinguish
subjects without trying to create such a number in countries where it is
not wanted.

          Tom Gindin

Paul Halliden <[email-masked]> on 07/14/2000 01:02:29 PM

To:   Tom Gindin/Watson/IBM@IBMUS, Stefan Santesson <[email-masked]>
cc:   Anders Rundgren <[email-masked]>, IETF-PXIX
      <[email-masked]>
Subject:  RE: QC DN "qualities". Was: I-D ACTION:draft-ietf-pkix-qc-04.txt

Tom

[Tom Gindin] There are several points at dispute.  Stefan explicitly
questioned the "requirement that 2 physical persons never can have the same
DN".

The contentious point is that this requirement has been dropped.  the
reason is that, in some jurisdictions there is simply no support for the
"unmistakable" concept.  Thus the subject name can be unique within the
CA's name space.  There is still a potential for mistaking that identity
with someone else not registered by the CA.  There is also ambiguity as to
whether two different names in the same space refer to the same physical
person - especially over time when a lot of the evidence supporting
identity (address, appearance, etc) can change.  In some countries, you can
address this issue by, e.g. referring to some unique national identity
number.  In others, such as the UK and USA there is no such thing.

[Tom Gindin] I actually do know something about this issue.  Have you read
the Permanent Identifier draft which Denis Pinkas and I wrote?  In it, an
individual may be identified by an ID issued by any assignment authority,
which does NOT have to be a government agency.

Regards
Paul Halliden

---

From: Paul Halliden <[email-masked]>
Date: Mon, 17 Jul 2000 09:59:35 +0100

Anders:

I said:
>>"unmistakable" concept.  Thus the subject name can be unique 
>within the CA's name space. 
>>

You replied:
>This last line is actually the thing requested by Denis and by me!

I think you will find that Denis is arguing against the "unmistakable"
concept (see the first paragraph of his mail dated 13 July).  As I
understand it, he has requested (Comment 1 in the same mail) that a CA does
not re-allocate an expired DN to someone other than the original user of the
name for the lifetime of the CA.  By expired DN, I mean a DN allocated to a
subscriber who no longer has any certificates issued by that CA.

>
>But even that is said to be impossible to achieve for reasons so
>far not particularly well explained.

I have not been arguing against that one - Indeed I think it is good
practice especially if long life documents have been signed by the subject
of a certificate. It will be difficult for some countries to achieve this
especially where there is a gap of many years between one DN ceasing to be
used and a new registration request involving the same DN.  However, I don't
think that should stop us aiming for the objective.

Anders, are we now in agreement?

Regards
Paul Halliden

---

From: "Anders Rundgren" <[email-masked]>
Date: Mon, 24 Jul 2000 09:56:28 +0200

Ed,
short reply

>> Probably you don't agree to the idea that a CA/RA should/can keep records of its subjects.
>> That makes the discussion somewhat uninteresting as this is the foundation of
>> most CAs in the X500-world.
>
>I don't see the connection between keeping records (which is mandated by law, for
>example) and *permanently using* those records.  Those records are history, not
>present.

The problem is that "history" means different things to different people.  If someone
dies he/she is "history" but not all RPs knows that.   I.e. "history" simply *cannot* be
a parameter in this ball-game!  

Or, maybe you could *here and now* describe how CAs should resissue DNs?!

Actually the only reason for me requiring that DNs are not reused is to cope with
(the highly likely) situation where a user "shows" a newly issued cert containing 
a DN/CA that the particular RP already knows about.  It should be a no-brainer
(=pure/simple/stupid software algorithm) to conclude that it is the same person. 

AGAIN: This requirement is COMPLETELY *independent* of the CA scope.
Be it national, federal, local, corporate, customer register etc.

Anders

---

From: Peter Sylvester <[email-masked]>
Date: Mon, 24 Jul 2000 15:10:16 +0200 (MET DST)

Since I have been CC:ed in this, here it goes. 

> Peter,
> 
> I have a feeling that this discussion has not much to do with technicalties.
Are you negatively criticising or appreaciating this? Do you want
to discuss techniques or other things? 

You are asking for a technical big brother feature that can be exploited
by RPs in order to solve a possible organisational problem, and this
technical final solution is not exactly acceptable in many places.

> It will be the *market* that will tell what is right and what is wrong!
Since I do not really know what you mean by market, and since I do
not agree with your first sentence I am not sure what I should answer. 
At least this is not a technical comment.

> 
> I don't think that the guys who sell certs with non-unique/resissued DNs will be very
> successful.  And that is what counts seen from my $-perspective.
IMHO a CA will do what the RPs require, and not the other way around. See below.
But this again is not a technical comment, so I don't care. 

> 
> You and Ed and other firm believers in other models will have to prove
> that there is a market for your ideas otherwise you will just find that your
> (probably) home-brewed certificates aren't accepted in too many places.
I am not clear of what model you are talking. If your model is that
you get a unique ID after birth tatooed on you body in a bar code together
with an implanted electronic device inside your body, no I do not
believe in that. I believe that technology is a means to help people
to live together or alone, and the technology can never require to
change organisational and cultural principles.

I don't have to prove anything, and I never had talked about what I think
would be a market, at least not recently during this thread (threat?) .

> 
> Pardon the flaming tone, but I think that this discussion is purely theoretical
> (=totally uninteresting) as long as no representatives from any CAs
> have confirmed that they will reuse DNs.  Cowards?  No, pure reality....
Request accepted, this applies also to me :-)

This is theoretical even when CAs will talk; as long as you do not know
what the requirement from RPs,  = application contexts,
the discussion is also useless.

> Not a single serious CA will reuse DNs! 
I have never said the contrary, nor did I confirm that. This depends on the
understanding and the context on how DN are constructed. 

If you allow to rely on that in any application context, you explicitely
put a requireemnt on the CA operator in a standard.  

If in a application context a CA operates the certificate management in that way, 
RPs may or may not rely on that, for example a tax payer ID is probabaly never allocated
twice. But this ID is created in the beginning in such a way that avoids
collisions. 

Or in other words, at least, I do not see that a CA would reuse a DN, 
if there is anything left to get to the old information by some reasonable means.  

> >Which can be done differently: You sign with the old cert and the new cert a doc
> >explaining that this belongs to the same person. 
> 
> Which requires that the old certs still exists which is not the case if you dropt it somewhere.
So: get the CA give you that statement of equivalence. This CAN be done
by reusing the DN, but you can also be done differently. 

If you loose everything of your identity, and you go to the RA
asking that you need a replacement of something that you do no longer 
have, what are you doing to prove that your are really the person?

> 
> >Or, in other words, the
> >equivalence will be established explicitely by the only interested party,
> >and not implicitely in an error prone way.
> 
> In what way (again assuming that the CA "knows" its subjects and do not reissue DNs) 
> whould my proposal be error-prone?

If you don't have to rely on something, you cannot have an error. 

If you rely on that, and either in the context of successor CAs or multiple
CAs, you just have at least moved the 'cert equivalence' problem to a CA cert equivalence
problem. 

How do you know that it is the same CA that issues the data? How do you
establish in a correct way the fact that two certs represent the same entity when
several CAs are involved? 

Or, I would like to see the simple algorithm to determine whether two certs
are identical, even in case of CA cert roll-over or replacement etc. 

W
/PS