Re: [Unbearable] FWD: Status of draft-ietf-tokbind-https

=JeffH <> Thu, 16 November 2017 02:53 UTC

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To: IETF TokBind WG <>
From: =JeffH <>
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Date: Thu, 16 Nov 2017 10:53:26 +0800
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Subject: Re: [Unbearable] FWD: Status of draft-ietf-tokbind-https
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From: Eric Rescorla <>
Date: Tuesday, November 14, 2017 at 4:11 AM
To: Andrei Popov <>
Cc: Leif Johansson <>se>, Vinod Anupam <>om>, 
<>rg>, "" 
Subject: Re: Status of draft-ietf-tokbind-https
Resent-From: <>rg>, Eric Rescorla <>
Resent-To: <>om>, <>om>, Dirk 
Balfanz <>om>, Adam Langley <>om>, 
<>om>, Jeff Hodges <>om>, 
Resent-Date: Tuesday, November 14, 2017 at 4:12 AM

On Mon, Nov 13, 2017 at 2:50 PM, Andrei Popov 
<> wrote:> I’m available in the morning; 
unfortunately, Dirk is not here, b>
 > Anupam can represent him.
 > Regarding the attack, it is not quite clear to me: Even assuming the
 > TP is willing to issue a token for Alice to connect to the Attacker
 > (which probably means the Attacker is a server known to the TP), this
 > token will be bound to the TB key Alice has created for use with the
 > attacker.
 > So the attacker cannot use this token to impersonate Alice to another
 > server (without also stealing the corresponding private key). Or am I
 > missing something?

I don't think so. I agree it's not an attack, it's just creating a 
confused token. I just worry whenever we have a protocol which allows 
this kind of confusion that either (a) we can turn it into an attack or 
(b) there's some other way to create confusion that is an attack.