[jdev] Alternate MUC Authentication Mechanisms

[Alex Milowski]

On Thu, Oct 21, 2010 at 2:00 PM, Dave Cridland <dave at cridland.net> wrote:
> On Thu Oct 21 20:08:42 2010, Alex Milowski wrote:
>>
>> Most simply, I want to be able to use something like DIGEST
>> authentication to keep the shared secret from being exposed.  I think
>> that is a simple request that is fairly straightforward to accomodate.
>>  A simple hash scheme doesn't protect against replay attacks and so
>> we do need the challenge in the mix somehow.
>
> Who are you assuming, in this threat model, is doing the replay?

Anyone who has somehow intercepted traffic.  One simple example would
be a server that is logging stanzas for some reason.

Also, if someone's server has been compromised and they join the
protected room, the attacker now has the authentication stanza
sequence.  With any kind of challenge whose response includes a nonce
and uses a one-way hash, the attacker is going to have a much harder
time decoding the response (if they can at all) and attempting to
crack the secret.  Of course, this depends on the method chosen.  They
most certainly can't use a replay attack.

-- 
--Alex Milowski
"The excellence of grammar as a guide is proportional to the paucity of the
inflexions, i.e. to the degree of analysis effected by the language
considered."

Bertrand Russell in a footnote of Principles of Mathematics