Re: [Ace] Security of the Communication Between C and RS

Stefanie Gerdes <gerdes@tzi.de> Wed, 19 December 2018 11:46 UTC

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To: Hannes Tschofenig <Hannes.Tschofenig@arm.com>, Ludwig Seitz <ludwig.seitz@ri.se>, Jim Schaad <ietf@augustcellars.com>, "ace@ietf.org" <ace@ietf.org>
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From: Stefanie Gerdes <gerdes@tzi.de>
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Date: Wed, 19 Dec 2018 12:46:24 +0100
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Subject: Re: [Ace] Security of the Communication Between C and RS
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Hi Hannes,

On 12/19/2018 12:36 PM, Hannes Tschofenig wrote:
> Hi Steffi,
> 
> Are you focused on token expiry or the case where a token + symmetric key has been leaked?

I am talking about the expiry of the keying material for RS that AS
provides to C.

> 
> Is the threat you are describing the case where the client uses DTLS/TLS with the RS (potentially long after a token has been presented), or the case where the client contacts the RS and presents a token?

I am worried about cases where the client communicates securely with RS,
e.g., using DTLS/TLS or object security, not about presenting the token
to RS.

Viele Grüße
Steffi