Re: Failure of AH

Brian E Carpenter <brian.e.carpenter@gmail.com> Mon, 20 March 2017 22:44 UTC

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Subject: Re: Failure of AH
To: Michael Richardson <mcr+ietf@sandelman.ca>, Christian Huitema <huitema@huitema.net>
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Cc: 6man WG <ipv6@ietf.org>
From: Brian E Carpenter <brian.e.carpenter@gmail.com>
Organization: University of Auckland
Message-ID: <a9e919b4-df76-f8d1-a7a9-3a632fc03b23@gmail.com>
Date: Tue, 21 Mar 2017 11:44:55 +1300
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On 21/03/2017 03:17, Michael Richardson wrote:
...
> So I'm just not worried about breaking AH.

That's well understood for today's AH. What bothers me is that
if we allowed en-route changes to headers now, without thinking this
aspect through, we might make any future AH-like authentication
mechanism impossible too. So at a minimum, we'd have to be sure
that inserted, modifiable and deletable headers are marked in some
way that will allow them to be excluded from authentication. That
was thought about years ago for IPv6 options, but not for extension
headers.

    Brian