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Re: [TLS] Deprecate SHA1 for signatures in TLS 1.3 (was Re: TLS 1.3 draft-07 sneak peek)

Martin Thomson <martin.thomson@gmail.com> Tue, 14 July 2015 19:55 UTC

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Date: Tue, 14 Jul 2015 12:55:52 -0700
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From: Martin Thomson <martin.thomson@gmail.com>
To: Andrei Popov <Andrei.Popov@microsoft.com>
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Subject: Re: [TLS] Deprecate SHA1 for signatures in TLS 1.3 (was Re: TLS 1.3 draft-07 sneak peek)
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On 14 July 2015 at 12:30, Andrei Popov <Andrei.Popov@microsoft.com> wrote:
> The downside is of course that the attacker can easily distinguish opportunistic clients from server-authenticating ones. Is this a concern for the opportunistic TLS community?

I raised the concern about this previously.  Opportunistic MitM
happens, and providing a strong signal that the connection won't be
(or couldn't be) authenticated somehow is a problem for that.  I'd
rather have opportunistic security be indistinguishable from "real"
security.  It also means that you don't have separate code paths to
support.

The anonymous modes serve a different purpose.  For instance tcpinc
could use them.

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