Re: [TLS] (selection criteria for crypto primitives) Re: sect571r1

Eric Rescorla <ekr@rtfm.com> Tue, 21 July 2015 19:42 UTC

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From: Eric Rescorla <ekr@rtfm.com>
Date: Tue, 21 Jul 2015 21:42:03 +0200
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To: Ilari Liusvaara <ilari.liusvaara@elisanet.fi>
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Subject: Re: [TLS] (selection criteria for crypto primitives) Re: sect571r1
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On Tue, Jul 21, 2015 at 7:20 PM, Ilari Liusvaara <
ilari.liusvaara@elisanet.fi> wrote:

> On Tue, Jul 21, 2015 at 11:30:15AM -0400, Dave Garrett wrote:
> > On Tuesday, July 21, 2015 10:47:05 am Ilari Liusvaara wrote:
> > > I thought that Brainpool curves weren't removed (even if those aren't
> > > explicitly in), which are random prime curves.
> > >
> > > Also, the security of binary curves seems quite questionable.
> >
> > Brainpool curves aren't in the TLS 1.3 draft, but they're not prohibited
> either.
> >
> > If there's no strong objection, I'd like to add them to the list, if
> > just to document the current NamedGroup registry. I could add a
> > recommendation to stick to standards track, for those worrying about
> them.
>
> Related: There's the following draft: draft-iab-crypto-alg-agility
> (currently in IETF LC) which contains the following:
>
> 3.4 National Cipher Suites
>
> "The default server or
> responder configuration SHOULD disable such algorithms; in this way,
> explicit action by the system administrator is needed to enable them
> where they are actually required."
>
> While the thing is about cipher suites, it also goes for curves.
>
> Also, Brainpool is much slower than the special prime stuff,
> so I think the defaults should be high-performance where it is
> not known to hurt security.
>
>
> This could also be applied to some actual ciphersuite stuff, namely
> ARIA and CAMELLIA (there doesn't seem to be any usable SEED ciphers).


I would be comfortable with taking a hard look at these.

-Ekr