RE: Basic Cert-2-Directory mapping question

[John_Wray@xxxxxxxx]

>As I read your suggestion, you want to add an element to the DN
>that directs the user to the appropriate directory. The new
>element is syntactically an RDN, but semantically is something
>different.  The resulting new-style DN appears to me to
>semantically comparable to an LDAP URL.


I don't think the proposed "dir" attribute is semantically very different
from any other naming attributes.  What we're trying to do with names in
certificates is to maintain the X.500 illusion that a DN uniquely
identifies an entry in some global directory.  But we don't have a single
global directory; instead we have a collection of directories which don't
talk to one another - i.e. instead of the single DN root assumed by X.500,
we actually have multiple roots, one for each directory.

The obvious way to resolve this sort of problem is to introduce a new
"meta-root" that sits above all the directory roots.  This corresponds to
adding an RDN to the most significant end of each DN that names the
particular directory within which the named entry lies.  Precisely how a
directory is named is TBD, but it must give an end-system enough
information to for a query for that directory, without requiring prior
knowledge of the directory, so an obvious possibility (for an LDAP
directory) is scheme and hostport portions of an LDAP URL.

Individual directories could either store this attribute explicitly within
the entry (which would mean that these directories could be directly
searched using the full DN) or, more likely, the "dir" attribute would have
to be removed before searching an individual directory.  So yes, the
mechanism for searching has to treat the "dir" RDN somewhat differently
from the other RDNs, but in terms of a naming model, it behaves just like
any other RDN.

As Bob points out, the "dir" attribute could be multi-valued, allowing
information about an entry to reside in multiple directories (provided that
the directories can all agree to use the same name for the entry).

John








"Slone, Skip" <skip.slone@xxxxxxxx> on 01/16/2001 09:16:13 AM

To:   "'Bob Jueneman'" <bjueneman@xxxxxxxxxx>
cc:   ietf-pkix@xxxxxxx
Subject:  RE: Basic Cert-2-Directory mapping question


Bob,

I'm glad to hear we agree on the nature of the problem.  From that point of
agreement, we can move the discussion to one of "what do we do about it?"

In abstract terms, it appears to me that "what we can do about it" falls
into two broad categories:
 1) we can create a mechanism for explicitly identifying the appropriate
directory, or
 2) we can remove the barriers that currently prevent the directory from
being discovered implicitly based upon existing information

I would say that your approach fits in category 1, while my approach fits
in
category 2. Either approach has validity IMHO and is worthy of
consideration.

As I read your suggestion, you want to add an element to the DN that
directs
the user to the appropriate directory. The new element is syntactically an
RDN, but semantically is something different.  The resulting new-style DN
appears to me to semantically comparable to an LDAP URL.

Assuming we're on the same page up to this point, I'll say that my concern
with this approach is that it changes the semantics of DN, potentially
causing interoperability problems in that both clients and servers that
understand the semantics as currently defined would have problems when
encountering the new-style name.  If we were to go with a "category 1" fix
to the problem, I would rather see a new mechanism employed, such as a new
PKIX-defined certificate extension that explicitly gives repository
location
information.  As a new construct, we would be free to define whatever
semantics we want, and could readily use existing concepts such as URLs.

Now, in defense of my approach, I think we can all probably agree that *IF*
the original concept of X.500-style distributed, global name resolution
were
a practical reality, we would be able to plug into the nearest DSA and find
the named entry regardless of where it resides physically. Of course I
emphasized the word "if" to imply that we can also probably agree that that
original X.500 concept is not going to occur anytime soon, if ever. What I
was proposing instead, was a "category 2" fix -- a way of removing that
barrier by providing an alternative way of doing distributed name
resolution.  The alternative mechanism I proposed was one which builds upon
an existing, working, global infrastructure that already has the requisite
registration infrastructure in place.  Without digging into the specifics,
I
would like to know if you or others believe that this *concept* has merit.

 -- Skip


-----Original Message-----
From: Bob Jueneman [mailto:bjueneman@xxxxxxxxxx]
Sent: Monday, January 15, 2001 2:11 PM
To: skip.slone@xxxxxxxx
Cc: ietf-pkix@xxxxxxx
Subject: RE: Basic Cert-2-Directory mapping question


Skip,

I don't particularly like the mechanism you've proposed, at least as
I understand it. But I absolutely and completely agree with you
as to the nature of the problem that has to be solved.

Civil attribute type names will always be with us, and hence must be
dealt with, for at least two fundamental reasons:

1.  An address is not a name, although it may be a pseudonym.  I
don't want to be forced to change my identity, or to an extent
my basis "self-hood," every time I change my ISP.  And I especially
don't want some system administrator telling me that my name
must be limited to 8 characters, or that I have to change my name
because someone else has already used that same name within
that same system administrator's ill-conceived naming scheme.

2.  E-mail address and other cyberspace identifiers fail to provide the
essence of PKI from a nonrepudiation standpoint, i.e., what I call the
"where do you send the sheriff" question.

Granted, not all uses of PKI will or should involve legal nonrepudiation.
But to the extent that at least some uses WILL have legal consequences,
then the establishment of a globally unique and credible identity that is
grounded in "meat-space" rather then cyberspace is absolutely essential.

For those legally binding transaction to be worth anything at all, they
have to be enforceable. And that means that a judgement may have
to be enforced upon someone, either by seizing the assets or putting
them in jail.  And only in science fiction does the sheriff ride off into
cyberspace to arrest someone.

If I as a relying party wish to trade with someone, then I either want to
charge her credit card (in which case PKI is demonstrably not necessary)
or I want to know that she is the Mary Smith who resides at 123 Anywhere
St,
Metropolis, NY.

The inclusion of that civil address not only servers to distinguish her
from the other Mary Smiths, but more importantly it establishes a nexus
or link between her identity and her probable whereabouts, and
probably valuable real property as well.

So civil addresses, both corporate or "organizationalPerson", or the
harder-to-deal-with residentialPerson type will presumably always
be with us, and will have to be dealt with.

And unfortunately, perhaps, here int he US the simple and inescapable
fact of the matter is that neither the federal nor the state governments
operate the type of presumptively authoritative name registration
authorities that are relatively common in other countries. I am perfectly
free to move from one city to another, or from address to another in
the same city, and to never notify anyone in authority at all, including
the tax authorities.  No one will ever say, "Papers, please."

(Granted, if I choose to do that I may not be able to register to vote,
but over half the population doesn't vote anyway.  And the last time
I registered, no one checked to see that I actually lived there -- that
one of the problems we have with our voting system, even outside
of the State of Florida.. And I may not be able to get a driver's license
in order to legally drive a car, but a lot of illegal immigrants don't have
driver's licenses either, although that doesn't keep them from driving.)

So merely trying to ignore the problem of civil addressing schemes
won't solve that problem.  And neither will various approaches that
make certain assumptions about monopoly name registration
authorities, or try to divine or impute where a directory containing
a particular name might be found based on some kind of a Karnak
mentalist act.

The primary issue is not the question of whether the name space
is flat or hierarchical, or how hierarchical, much less what the
"approved" schema is.  What will be, will be, for reasons that
are beyond our scope and power to influence, even if we wanted
to.

So.

We cannot force a person to deposit his certificate or other useful
information into a specific directory, even if we wanted to.  Nor can
we reliably impute a likely directory where such information might
be found, at least in the absence of a monopoly or governmental
mandate.

The best we can do is to ASK the user where he has deposited
such information, if anywhere, and to include that information
EXPLICITLY in any directory or pseudo-directory reference, such
as a DN.

Although at one time I liked the notion of prefixing the DN with a
URL, I have come to believe that John Wray's suggestion is the
better way forward.

He said:
>
>Bob,
>
>Accepting the fact that the X.500 dream of a single global directory is
not
>going to happen any time soon, DNs can still be turned into globally
>significant pointers into a federation of directories in the way you
>suggest, but it doesn't require altering the DN syntax (and therefore
>doesn't have to break existing implementations).  All that's needed is a
DN
>attribute that names the particular directory within which the name
>resides.  e.g. instead of "c=us;..;cn=My Name" you'd have "dir=My
>Directory;c=us;...;cn=My Name", where "My Directory" is the URL of a
>directory access point.

By including an explicit directory qualifier of the form dir="directory
URL"
at the root (top) of the RDN chain, we have implicitly qualified all of the
rest
of the RDN, which is a Good Thing.

By defining the syntax of the "dir" attribute appropriately, we could
include
both the access type (LDAP, http, etc.) and port number appropriately,
either a default or explicitly indicated.

And by making the dir component multivalued, we could accommodate
a choice of multiple directories and multiple directory types.

Once again -- the essence of the problem is not the format of the directory
name but where a directory containing that name can be found.
Including that information as a top-level qualifying component solves that
problem (and potentially several others, such as name scope qualification)
very neatly.

Bob

Robert R. Jueneman
'Security Architect
Novell, Inc. -- the leading provider of Net services software
>
>
>
>
>
>
>
>>>> "Slone, Skip" <skip.slone@xxxxxxxx> 01/15/01 09:08AM >>>
>Oscar,
>
>No offense taken, thus no apology needed.
>
>My comments from the soapbox last week were actually intended for the
>community at large, and were meant to convey frustration at the apparent
>unwillingness of solution providers in general to hear about -- and solve
--
>real world problems that are faced by users like myself in large, complex
>environments.
>
>When I say "my environment is not so simple," the response I hear is
"let's
>not talk about the complexity; let's make some simplifying assumptions
>instead."
>
>When I say "I have a nail AND a screw and need to put them both in the
>wall," the response I hear is "we have provided you with a perfectly
>adequate hammer, therefore you don't have a screw."
>
>As I was using the nail/hammer analogy, dc-based names are the nails;
>civil-attribute-based names are the screws. No matter how good a job my
>company does of using nails and nails alone, we still have tens of
thousands
>of trading partners, many of whom prefer screws to nails and will continue
>to use them indefinitely. Without a screwdriver, it's hard to do business
>with them.
>
>I don't really care what the screwdriver looks like.  I've suggested a
>fairly simple design that I think will work. So far, no one has commented
on
>the design. What I've heard instead is a chorus of "we still don't like
>screws."  Well, I don't like them either, but I still have to deal with
>them.  If I'm simply overlooking a screwdriver that we have lying around
>somewhere, I would appreciate someone pointing it out to me.
>
> -- Skip
>
>
>-----Original Message-----
>From: Oscar Jacobsson [mailto:oscar.jacobsson@xxxxxxxxxxx]
>Sent: Thursday, January 11, 2001 5:16 PM
>To: Slone, Skip
>Cc: 'Sharon Boeyen'; ietf-pkix@xxxxxxx
>Subject: RE: Basic Cert-2-Directory mapping question
>
>
>> From: Slone, Skip [mailto:skip.slone@xxxxxxxx]
>> In response to this, I'm inclined to join Sharon on Marshall's soapbox
and
>> echo her words:
>>
>> "... I believe a more constructive approach is to accept the fact that
>> different parts of the world and different environments will use a
variety
>> of nameforms ... We are not the global naming police either and should
not
>> try to impose the rules that anyone uses to name entities to which they
>> issue certificates."
>
>I'm sorry if I came across as clamouring for rules be imposed. I know that
>this working group has a tendency to be wary of suggestions that don't
cater
>for distinguished names containing cat MPEGs, so I should probably have
been
>more careful. The requirements I suggested were for a possible naming
>standards document, conformance to which need not be enforced.
>
>The case at hand is not, IMHO, one of dictating that "all distinguished
>names must be according to our will, or you shall feel our wrath". A
>document however, outlining a naming strategy that would require of the
>users of certificates named accordingly no a-priori knowledge of their
>issuer (save for eventually having to reach something explicitly trusted
in
>the chain) in order to perform path validation, is something I would
>personally consider very valuable indeed. I'm reasonably confident that
>organizations intending to act as certification authorities or trusted
third
>parties would agree.
>
>> And to quote someone Sharon and I both know, "If all you have is a
hammer,
>> every problem looks like a nail."
>
>It seems I was less than clear here as well. :-(
>
>My intention was to point out that there are actually two separate
problems
>here (one nail, if you will, and one screw) each looking for its own
>solution:
>
>1. Defining a repository, and subsequently entry, discovery process for
>arbitrarily named entries.
>
>2. Defining a naming scheme that _if applied_ would automate this
repository
>and entry discovery process.
>
>I am only trying to address the second of these problems. The first is
only
>an issue because nobody seems to have properly addressed the second before
>deploying certificates on the Internet en masse. The further we wait
before
>addressing number two, the more of a problem number one will become.
>
>I should probably make a habit of pointing out that the opinions stated
here
>are my very own, and not necessarily those of my employer.
>
>Cheers,
>
>//oscar