Hi Phill,
On 02/09/2012 03:40 AM, Phillip Hallam-Baker wrote:
I think we have a set of requirements that point to a need for three
separable technologies:
1) A means by which a site can express the intended security policy
2) An append only notary service
3) A means by which a client can obtain security policy curated by a
fourth party
Each of these components can be designed in stovepipe fashion to only
serve one set of requirements or they can be conceived in slightly
more general form.
For example, Convergence, SK and CT all involve some form of append
only notary. Such a facility would have far more general applicability
than just addressing public keys. It might well be easier to get a
broad range of parties establishing and supporting the necessary
ecology of notary service providers if they are designed in such a
fashion that they can be used for general purposes.
So I will make separate protocol proposals in each area, but
Great. That's what's needed for progress to be made here. Send
the I-D URLs here as soon as you can!
More opinions on your categorisation and its utility would also
be good, (e.g. it clearly doesn't try to address the secure-mail-from-
all-to-all problem, right?).
I think
what we are designing is going to be easier to deploy if we give some
thought to re-usability of components and dual use.
Well... that assumes that there are folks out there who want to
re-use stuff. To some extent this space, for now, seems to be
a bit more solipsistic. Maybe the people proposing to solve all
problems aren't quite as confident as they claim? (...he said
deliberately, but honestly, trying to provoke people out of
silence:-)
S.
PS: I do appreciate your being constructive on this.
On Wed, Feb 8, 2012 at 9:11 PM, Stephen Farrell
<[email protected]> wrote:
<trying to poke things along a bit more actively hat on>
So S/MIME works fine in many cases but does not work well
between random people connected to the Internet, unlike email.
That's a pity.
Its not an easy problem though, XMPP have been trying for a
good while and we don't even seem to have a good solution for
SIP or Diameter which ought be much easier.
I guess if this discussion lead to a way to manage keys that
could work at the same scale as email that would be a major
advance. I don't expect that myself.
And of course, whatever the right answer there (if there
is one) is maybe very different from how we might manage keys
for web servers or MTAs or XMPP servers.
Maybe we ought also think about whether or not the same key
management scheme is right for all those or not as part of
this too and whether we're able to solve all or just some/one
of those problems.
Put another way: maybe it'd be better to tighten the focus
a teeny bit more on this list. Specific suggestions for topics
welcome. Why not start a new thread with your favourite
problem that's worth solving and maybe solveable. (Being the
IETF, we're not very interested in other things in the end:-)
S.
PS: I bet I'm not the only one who can no longer associate
the subject line with the content. Be good to be better at
that since it'll help to try move towards some concrete
outcomes here.
On 02/09/2012 01:22 AM, Phillip Hallam-Baker wrote:
Alice has three mobile phones and six laptops.
Using embedded keys in those devices for authorization is no problem
since each device can have a separate private key and the
authentication server tracks the fact that there are nine devices that
might authenticate Alice.
The same model can even be made to work for confidentiality. Alice can
read her DRM protected Kindle content on any one of those devices.
(Though there may be limits on how many devices the DRM scheme will
permit).
Trying to make S/MIME email work in that scenario is futile. The
sender only tracks one private key for Alice. So Alice has to export
her private key to all her S/MIME clients. Not only is that terrible
security practice, it is too much work. Worse, Alice has to repeat the
process once a year.
That is why I no longer believe that end-to-end is a desirable
quality. A security requirement that does not consider the cost it
imposes versus the risks it mitigates is ideology.
On Wed, Feb 8, 2012 at 4:52 PM, Stephen Kent<[email protected]> wrote:
At 3:03 PM -0500 2/8/12, Phillip Hallam-Baker wrote:
But authentication works in that scenario because the protocols can
allow
each user to have as many keys as they need. The key is not shared
across
devices, the protocols allow for multiple cards per end user
Sorry, I don't understand you comment.
Steve
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