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Re: [TLS] Comments/Questions on draft-gutmann-tls-encrypt-then-mac-00.txt

Michael D'Errico <mike-list@pobox.com> Wed, 25 September 2013 21:17 UTC

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Date: Wed, 25 Sep 2013 14:17:07 -0700
From: Michael D'Errico <mike-list@pobox.com>
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To: Bodo Moeller <bmoeller@acm.org>
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Cc: TLS Mailing List <tls@ietf.org>
Subject: Re: [TLS] Comments/Questions on draft-gutmann-tls-encrypt-then-mac-00.txt
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> http://www.ietf.org/internet-drafts/draft-bmoeller-tls-downgrade-scsv-00.txt

I think that the server MUST send a FATAL alert only if it would
not have been willing to negotiate the lower TLS version in the
absence of the SCSV.

A WARNING alert from the server (or some extension_data with more
information) lets the client decide whether to continue.  Both
sides can keep track of these occurrences for further investigation
by interested admins at their leisure (not via calls to the help
desk).

Also RFC 3546 and 4366 have been obsoleted by RFC 6066.

Mike

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