Re: [TLS] A closer look at ROBOT, BB Attacks, timing attacks in general, and what we can do in TLS

Eric Rescorla <ekr@rtfm.com> Fri, 15 December 2017 18:16 UTC

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From: Eric Rescorla <ekr@rtfm.com>
Date: Fri, 15 Dec 2017 10:15:23 -0800
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To: Watson Ladd <watsonbladd@gmail.com>
Cc: Ilari Liusvaara <ilariliusvaara@welho.com>, "tls@ietf.org" <tls@ietf.org>
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Subject: Re: [TLS] A closer look at ROBOT, BB Attacks, timing attacks in general, and what we can do in TLS
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On Fri, Dec 15, 2017 at 10:12 AM, Watson Ladd <watsonbladd@gmail.com>; wrote:

> We can force a rotate of all certs in 90 days, and I don't think most
> people will notice.
>

Unfortunately, there are plenty of longterm certificates with lifetimes >>
90 days.

-Ekr


>
> On Fri, Dec 15, 2017 at 10:07 AM, Eric Rescorla <ekr@rtfm.com>; wrote:
> > I'm not quite following how this helps. It's true that if SHA-256 is
> broken,
> > we're in serious trouble, but that's largely because of the fact that
> that's
> > what people's certificates have, so clients really can't refuse to
> support
> > SHA-256 certificates. So, how does adding new algorithms help? (That's
> why I
> > would argue that the existing SHA-384 support doesn't help).
> >
> > -Ekr
> >
> >
> > On Fri, Dec 15, 2017 at 9:46 AM, Ilari Liusvaara <
> ilariliusvaara@welho.com>;
> > wrote:
> >>
> >> On Fri, Dec 15, 2017 at 02:57:33PM +0000, Andrei Popov wrote:
> >> > From: TLS [mailto:tls-bounces@ietf.org] On Behalf Of Ilari Liusvaara
> >> > > Even nastier dependency: SHA-2. If that breaks, currently both TLS
> >> > > 1.2 and 1.3 break. There are no alternatives defined.
> >> >
> >> > Here's an attempt to define a SHA-2 alternative:
> >> > https://tools.ietf.org/html/draft-wconner-blake2sigs-01
> >>
> >> Also would need TLS ciphersuite codepoints with alternative handshake
> >> hash algorithms.
> >>
> >>
> >> -Ilari
> >>
> >> _______________________________________________
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> >
> >
> >
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> >
>
>
>
> --
> "Man is born free, but everywhere he is in chains".
> --Rousseau.
>