Subject: [pkix] Whitelisting

From: "Erik Andersen" <[email-masked]>
Date: Fri, 17 May 2013 12:31:58 +0200

There were some ideas about whitelisting of certificates. What is the
status?

Erik

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From: Erwann Abalea <[email-masked]>
Date: Fri, 17 May 2013 15:57:18 +0200

Are you talking about MECAI, Google CT, EFF Sovereign Keys, and similar ideas?

--
Erwann.

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From: [email-masked] (Martin Rex)
Date: Fri, 17 May 2013 16:09:55 +0200 (CEST)

I assume Erik was asking about an OCSP Extension "Proof of cert issuance",
such as a CertHash included with an OCSP "good" status.

One example for an "existing solution" was mentioned by
Johannes Merkle and is quoted here:

http://www.ietf.org/mail-archive/web/pkix/current/msg32667.html

-Martin

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From: "Erik Andersen" <[email-masked]>
Date: Fri, 17 May 2013 16:31:05 +0200

The reason I am asking is that I am sitting with a document that I am
commenting. It says:

"In certain deployments, additional support is necessary to further restrict
the usage of certificates based on their serial numbers and issuers. This
restriction is known as certificate white listing or certificate pinning,
and is currently being defined in the IETF"

I was trying to find out whether that is true and if yes, what the status
is.

Erik

-----Oprindelig meddelelse-----
Fra: Martin Rex [mailto:[email-masked]] 
Sendt: 17. maj 2013 16:10
Til: Erwann Abalea
Cc: Erik Andersen; PKIX
Emne: Re: [pkix] Whitelisting

One example for an "existing solution" was mentioned by Johannes Merkle and
is quoted here:

-Martin

Erwann Abalea wrote:
> > There were some ideas about whitelisting of certificates. What is 
> > the status?

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From: Adam Langley <[email-masked]>
Date: Fri, 17 May 2013 10:35:31 -0400

> I was trying to find out whether that is true and if yes, what the status

It is possibly this document:
https://tools.ietf.org/html/draft-ietf-websec-key-pinning-04

Cheers

AGL

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From: "Piyush Jain" <[email-masked]>
Date: Fri, 17 May 2013 08:06:11 -0700

And this
http://tools.ietf.org/html/draft-perrin-tls-tack-02

> -----Original Message-----
> From: [email-masked] [mailto:[email-masked]] On Behalf Of
> Adam Langley
> Sent: Friday, May 17, 2013 7:36 AM
> To: Erik Andersen
> Cc: PKIX
> Subject: Re: [pkix] Whitelisting
> 
> > "In certain deployments, additional support is necessary to further
> > restrict the usage of certificates based on their serial numbers and
> > issuers. This restriction is known as certificate white listing or
> > certificate pinning, and is currently being defined in the IETF"
> >
> > I was trying to find out whether that is true and if yes, what the
> > status is.
> 
> _______________________________________________
> pkix mailing list
> [email-masked]
> https://www.ietf.org/mailman/listinfo/pkix

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From: Stefan Santesson <[email-masked]>
Date: Thu, 30 May 2013 00:21:02 +0200

Erik,

There was also some discussions about a white-list OCSP extension with
proof of existence.
That never took of into a WG effort.

However, to create such extension would be a perfectly valid effort now
when the updated OCSP is published (to be RFC 6960)
But as PKIX is closing down, it must be done some place else.

/Stefan

On 5/17/13 4:31 PM, "Erik Andersen" <[email-masked]> wrote:

>restrict

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From: Stefan Santesson <[email-masked]>
Date: Thu, 30 May 2013 00:37:54 +0200

Most of what got defined in RFC 3739 was good.

It is a very highly deployed standard in the EU.
At the time, EU defined Qualified Certificates as something that was only
issued to a natural person.

However, there is one requirement of RFC 3739 that was doomed to fail
given enough time.
And that is the required list of attributes in section 3.1.2.

In particular this sentence:
"Other attributes MAY also be present; however, the use of other
   attributes MUST NOT be necessary to distinguish one subject name from
   another subject name.  That is, the attributes listed above are
sufficient to ensure unique subject names."

Yes, I wrote that. And I fully admit my mistake.

In particular two things have happened that makes this requirement plain
wrong and obsolete.

1) EU has now concluded that QC can be issued not only to people, but to
organisations.
2) X.520 has defined a new attribute for organisationIdentifier

That attribute is much more suitable to use for an organisation unique
identifier rather than serialNumber. Especially if the cert includes
information about both a person and an organisation.
So the organisationIdentifier attribute may very well be necessary to
achieve uniqueness in many cases.

It is nether very future proof to assume that serialNumber will be used
forever.
There are other more suitable attributes that you may want at times.

As an example, there is a local Swedish attribute for national Swedish ID
numbers used in many Swedish PKI deployments. They will never fit the
attribute requirement of RFC 3739.

ETSI is currently making interop profiles for QC that are not natural
persons.
But the EU QC profile EN 319 412-5 relies on RFC 3739.

This has created a deadlock where the interop profile will have to violate
RFC 3739, unless RFC 3739 is updated.

I will initiate an effort to create an update RFC that opens up this
requirement of RFC 3739. This will be in the form of a DIFF (OLD: NEW:)
update document.

I raise the issue here to get feedback. This probably has to go as a
private submission, but as this list is still open, we can always discuss
the issue here.

/Stefan

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From: Denis <[email-masked]>
Date: Thu, 30 May 2013 16:00:12 +0200

Stefan,

Thank you for raising the issue to the list.
However, at the time the document was written, there was no mistake.

In France, nobody may get a certificate representing a company or an 
organization.
Thus a QC cannot be issued to an organization.

However, a certificate could be issued to a department within an 
organisation.
Thus identifying the department within the organisation (as well as the 
organisation of course) is necessary.
In other words, using only an organisation identifier is insufficient.

The point which should be discussed on the list is the content of 
proposed "organisationIdentifier".
It would be interesting to know what you propose for it in principle, 
before issuing a diff document.

Denis

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From: Russ Housley <[email-masked]>
Date: Thu, 30 May 2013 10:56:31 -0400

Seems to me that a very short update can be written.  No need to open the whole document.

Russ

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From: Stefan Santesson <[email-masked]>
Date: Thu, 30 May 2013 17:06:49 +0200

Yes, I agree.

/Stefan

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From: Stefan Santesson <[email-masked]>
Date: Thu, 30 May 2013 21:40:04 +0200

Denis,

The content of the organisationIdentifier is an interesting question. But
it can be done separate to the discussion of the need for an update of
3739.
The organisationIdentifier is already defined in X.520, so we have no
power over it. It is an unstructured string, much like serialNumber is,
except it is not limited to PrintableString which is a good thing.

What we need to agree on in the case of 3739 is simply to remove the
requirement that any particular set of attributes must provide a unique
identity, and simply accept that the unique identity is provided by the
complete set of any attributes.

/Stefan