[Security] Reminder :: Draft feedback on "C2C authentication using TLS"

Dirk Meyer dmeyer at tzi.de
Sun Aug 24 17:00:49 CDT 2008

Pavel Simerda wrote:
> On Sun, 24 Aug 2008 20:59:22 +0200
> Dirk Meyer <dmeyer at tzi.de> wrote:
>> Johansson Olle E wrote:
>> > Could this functionality benefit from some sort of Disco support to
>> > check what the other side supports, before setting up the
>> > connection?
> +1
>> You could put the stuff I added as <offer> to the disco stuff. But it
>> must also work serverless. And when I work link-local I can not use
>> disco#query before connecting.
> I don't know much about link-local messaging but if it uses DNS (which
> it does), it can use it for discovery. (I don't say it's good or bad.)

We could hook into the txt records and add the offer there.

> But then I would expect a real-world usecase with XML examples for
> better understanding.

Yes, I know. But since all people on the list know what it is about I
skiped that part. It will be added later.

> And it would be good to resolve the "SRP vs. SAS vs. whatever else"
> issue or leave this possibility out of the spec before it's resolved
> (so we aren't pushed by the developers to keep what we put there
> already).
> A short paragraph about other possibilities to be included would do.

Agreed. The list in 'Requirements' is based on what is a RFC now. I
should add a note that anything that can be used with TLS can also be
used at this point. And if there will be SAS support in TLS it can be
used. If a client does not support it, it can simple ignore the <sas>
offer. So a note: 'ignore offers you do not know' and 'there can be
more in the future' is needed.

> Furthermore, it's important to hear from Peter Saint-Andre and maybe
> others about the disco features and other interoperability issues.

Yes. If we can put the offer from starttls in the disco feature and
use txt records, that would be nice to have. Or offer disco#query as
feature before starttls. But the second offer in proceed can not be
avoided since only at this point the receiver knows what it wants to
support for that specific client based on what it can verify.

Thanks for the comments.


One nuclear bomb can ruin your whole day.

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