Subject: [therightkey] RA vs CA

From: Ben Laurie <[email-masked]>
Date: Wed, 8 Jan 2014 18:30:14 +0000

On 27 December 2013 10:06, Ralph Holz <[email-masked]> wrote:
> Hi,
>
> [The EFF's count]
>
>>> You can't calculate the number of CAs the way the EFF tried to. An
>>> intermediate certificate does not equate to a CA. Pretending it does to
>>> peddle an alternative PKI scheme calls into question their veracity.
>>>
>>
>> I disagree strongly. I have an intermediate certificate. I am as
>> powerful CA as a result.
>> Please also see these estimates which are even higher:
>>
>> https://zakird.com/slides/durumeric-https-imc13.pdf
>>
>> "Identified 1,832 CA certificates  belonging to 683 organizations"
>> "311 (45%) of the organizations were provided certificates by
>> German National Research and Education Network (DFN) "
>
> I was there at IMC and spoke with Zakir. He was not aware of the fact
> that the private keys to all the intermediate certificates are held by
> the central DFN Verein, not the RAs themselves. In the case of DFN, the
> intermediate certs only identify the RAs. The RAs do not carry signing
> power.

What is the function of an RA, then, if not to tell a CA "sign this"?

---

From: "Jeremy Rowley" <[email-masked]>
Date: Wed, 8 Jan 2014 11:33:49 -0700

The role of the RA varies a lot depending on the CA and industry. For
example, some CAs use RAs only to collect face to face documentation
(similar to a notary).  The CA will still do a record check, verify the
identity, etc.  The existence of an RA does not necessarily mean the CA is
signing whatever is put in front of it.  The only way to know the scope  of
the RA function is to ask the CA.

Jeremy

-----Original Message-----
From: therightkey [mailto:[email-masked]] On Behalf Of Ben
Laurie
Sent: Wednesday, January 08, 2014 11:30 AM
To: Ralph Holz
Cc: [email-masked]; Seth David Schoen
Subject: [therightkey] RA vs CA

On 27 December 2013 10:06, Ralph Holz <[email-masked]> wrote:
>>> intermediate certificate does not equate to a CA. Pretending it does 
>>> to peddle an alternative PKI scheme calls into question their veracity.
>>>
>>
>> "311 (45%) of the organizations were provided certificates by German 
>> National Research and Education Network (DFN) "
>
> the central DFN Verein, not the RAs themselves. In the case of DFN, 
> the intermediate certs only identify the RAs. The RAs do not carry 
> signing power.

What is the function of an RA, then, if not to tell a CA "sign this"?
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---

From: "Jeremy Rowley" <[email-masked]>
Date: Wed, 8 Jan 2014 11:38:23 -0700

To add some clarification on why the EFF probably over-counted:

We create intermediate certificates all the time for customers, typically
for access control or to minimize the potential impact of the intermediate's
revocation. However, the intermediate stays within our PKI and is subject to
our verification process and control.  This doesn't make it a separate
issuer.  The RA tells us who is authorized to get a certificate off that
intermediate, but they don't dictate the validation or issuance process. 

Again (and unfortunately), the scope of control over an intermediate varies
widely depending on the CA. 

Jeremy

-----Original Message-----
From: therightkey [mailto:[email-masked]] On Behalf Of Jeremy
Rowley
Sent: Wednesday, January 08, 2014 11:34 AM
To: 'Ben Laurie'; 'Ralph Holz'
Cc: [email-masked]; 'Seth David Schoen'
Subject: Re: [therightkey] RA vs CA

Jeremy

---

From: Ralph Holz <[email-masked]>
Date: Wed, 08 Jan 2014 19:48:32 +0100

Hi,

> What is the function of an RA, then, if not to tell a CA "sign this"?

I'll add the following in addition to what Jeremy said: the term RA is
used with different meanings by CAs. E.g. during the Comodo incident in
2011 (the one by Comodohacker), it became clear that the RA had access
credentials stored that allowed it to trigger certification by the CA.
This was really what others might call a reseller or possibly a
subordinate CA.

In the case of DFN, it is different. The RAs are 1) identifiers in
intermediate certs and 2) carry out paperwork. I request a server cert
by creating a CSR in DFN's online interface, but I send a paper form to
the local RA who will then contact me to verify that I am indeed a TUM
employee with control over the server (and in case of S/MIME, see my
passport). There does not seem to be an automated trigger from the RA
that causes certification; rather it seems to be a delegation of certain
duties. The whole thing is specified here:

https://www.pki.dfn.de/fileadmin/PKI/Konzept_DFN-PKI.pdf

Ralph

-- 
Ralph Holz
I8 - Network Architectures and Services
Technische Universität München
http://www.net.in.tum.de/de/mitarbeiter/holz/
Phone +49.89.289.18043
PGP: A805 D19C E23E 6BBB E0C4  86DC 520E 0C83 69B0 03EF

---

From: Phillip Hallam-Baker <[email-masked]>
Date: Wed, 8 Jan 2014 14:29:11 -0500

There is a problem here with the conventional nomenclature.

The term CA can mean the legal entity or the machine in control of the
private key. As with the original RSA paper that asserted Alice is a Turing
machine, this is a problem.

The EFF study conflates the term RA with issue under an intermediate
certificate, the two are completely separate. There are plenty of examples
of an RA that issues directly under the CA root and there are plenty of
examples where a CA manages an intermediate root directly.

The best definition of the RA function is that the RA is responsible for
authorizing issue of certificates. But authorization from the RA is only a
necessary condition, it is not necessarily sufficient.

In the WebPKI an affiliate or enterprise customer may run an RA, but the CA
is now required to perform certain validation functions directly. Since you
probably don't want to have the validation taking place in the room with
the private key the logical arrangement is again a RA.

-- 
Website: http://hallambaker.com/