Re: [secdir] dir review of draft-laurie-pki-sunlight-05

Tobias Gondrom <tobias.gondrom@gondrom.org> Sun, 10 February 2013 02:54 UTC

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Date: Sun, 10 Feb 2013 10:54:47 +0800
From: Tobias Gondrom <tobias.gondrom@gondrom.org>
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Cc: secdir@ietf.org, iesg@ietf.org, draft-laurie-pki-sunlight.all@tools.ietf.org, jhutz@cmu.edu
Subject: Re: [secdir] dir review of draft-laurie-pki-sunlight-05
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On 10/02/13 04:47, Ben Laurie wrote:
> On 9 February 2013 13:34, Tobias Gondrom <tobias.gondrom@gondrom.org> wrote:
>> Hi Ben,
>>
>> I also just read through your draft in version -07.
>> I can see the draft consists of two parts:
>> 1. data structure
>> 2. protocol.
>>
>> For part #1 the data structure: in case you are not aware of it, some
>> years ago the IETF LTANS WG has done something a bit similar in a more
>> generic way (i.e. for any data not only for certificates) in form of
>> RFC4998 and RFC6283
> Interesting. I was not aware of these. From a quick skim they are
> indeed similar, but would need a bunch of added machinery to get them
> to where CT is (e.g. not append only, no concept of MMD).
You are welcome.
I believe the gap is mostly towards the protocol side (e.g. including
MMD). As the RFCs only define the data structure.


>> with a number of implementations by major ECM and
>> DMS vendors.
> No idea what ECM or DMS are in this context.
ECM: Enterprise Content Management
DMS: Document Management System
(Systems that store electronic documents/data.
And protect the proof of integrity / non-repudiation with Timestamps and
RFC4998/RFC6283.)


>
>> Just as a thought, maybe helpful looking at or even for re-use instead
>> of re-inventing the wheel?
>>
>> Best regards, Tobias
>>
>>
>>
>> On 30/01/13 18:15, Ben Laurie wrote:
>>> On 29 January 2013 21:28, Jeffrey Hutzelman <jhutz@cmu.edu> wrote:
>>>> On Tue, 2013-01-29 at 11:35 +0000, Ben Laurie wrote:
>>>>> On 24 January 2013 19:06, Jeffrey Hutzelman <jhutz@cmu.edu> wrote:
>>>>>> Similarly, as an anti-spam measure, this document proposes that logs accept
>>>>>> only certificates which chain back to a known CA, and requires that logs
>>>>>> validate each submitted certificate before appending it to the log.  This
>>>>>> sounds good, but it's not the only possible mechanism, and so I think MUST
>>>>>> is too strong here.  Additionally, there is no discussion of the security
>>>>>> implications if a client depends on a log to do this and the log does not
>>>>>> actually do so.  Rather than requiring that logs validate every submitted
>>>>>> certificate, the document should only RECOMMEND that they do so, and make
>>>>>> clear that clients MUST NOT depend on such validation having been done.
>>>>> On second thoughts, whilst that is an effective anti-spam measure, it
>>>>> is also part of the functionality of CT: i.e. to identify misissue and
>>>>> give some means to do something about it. The CA check ensures we have
>>>>> someone to blame for misissue.
>>>> Hrm.  I sort of thought the idea was for the logs to be untrusted
>>>> repositories, able to be audited but not themselves expected to detect
>>>> problems.  If logs are expected to do validation of this sort, is there
>>>> a way for a third party to discover whether they are doing so (or at
>>>> least, whether they are accepting certificates they shouldn't)?
>>> A third party can indeed verify this - they just watch the log like
>>> any monitor does.
>>>
>>>>> I am not averse to suggestions that achieve the overall aim, but I
>>>>> don't see the virtue of leaving it vague in the description of the
>>>>> experiment we are actually running.
>>>> I'm not suggesting vagueness; rather, I'm merely suggesting downgrading
>>>> a MUST to a SHOULD, which is still quite strong.  What happens if
>>>> someone wants to start logging certs issued by a private CA, or
>>>> self-signed certs they have observed, or...?
>>> I don't see an issue with logging certs from a private CA. As for
>>> self-signed certs, I don't see the point, but I guess if someone
>>> figures out a point we can relax it in the next version.
>>>
>>>> I'm suppose I'm OK with keeping the scope narrower than that for
>>>> purposes of the experiment, as long as it is possible to relax the
>>>> requirement later without breaking the system.  Hence the importance of
>>>> making it clear that clients must not rely on logs to have done
>>>> validation (on which point I think we've already reached agreement).
>>> Cool.
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