Re: [rtcweb] Identity and PSTN gateways

Randell Jesup <randell-ietf@jesup.org> Tue, 03 April 2012 22:16 UTC

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Date: Tue, 03 Apr 2012 18:13:09 -0400
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Subject: Re: [rtcweb] Identity and PSTN gateways
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On 4/3/2012 4:47 PM, Iñaki Baz Castillo wrote:
> 2012/4/3 Randell Jesup<randell-ietf@jesup.org>:

>> If it's
>> SDES-SRTP, then the TURN server could tap off the encrypted traffic for
>> later analysis by whomever has the key,
>
> And who has the key? The trusted HTTPS server.
>
>> or be supplied with the key to do
>> realtime decode-and-forward, analysis or traffic modification.
>
> And who has the key? The trusted HTTPS server.
>
> So what is the real problem? the trusted HTTPS server when attacked.
> The *same* is true in case of DTLS-SRTP when the HTTPS server or the
> identity provider (via TLS again) is attacked.

Ah, but Identity Provider != Service Provider.  (It may be the same, but 
for smaller entities it wouldn't be - typically the Idp's will be "big 
sites" that act as primary email hosts, like Google.)  Yes, it's 
well-known in the discussion that if the service provider == Idp then 
the Idp can MITM you (or at least make things more complex; it may be 
possible to use key-chaining to reduce risk some).

> Please read the mail "On DTLS-SRTP trust model (and consideration for
> SDES-SRTP)" from Fabio. DTLS is not the panacea.

Nothing is.  :-)


-- 
Randell Jesup
randell-ietf@jesup.org