Re: [TLS] Ala Carte Cipher suites - was: DSA should die
"Blumenthal, Uri - 0553 - MITLL" <uri@ll.mit.edu> Mon, 13 April 2015 22:22 UTC
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From: "Blumenthal, Uri - 0553 - MITLL" <uri@ll.mit.edu>
To: "'ynir.ietf@gmail.com'" <ynir.ietf@gmail.com>, "'geoffk@geoffk.org'" <geoffk@geoffk.org>
Thread-Topic: [TLS] Ala Carte Cipher suites - was: DSA should die
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Date: Mon, 13 Apr 2015 22:22:14 +0000
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Subject: Re: [TLS] Ala Carte Cipher suites - was: DSA should die
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Yes. My expectation here is that "good" constructs are composable. "Composable with caveats" are not good, and shouldn't be included in a-la carte selection. -- Regards, Uri Blumenthal Voice: (781) 981-1638 Cyber Systems and Technology Fax: (781) 981-0186 MIT Lincoln Laboratory Cell: (339) 223-5363 244 Wood Street, Lexington, MA 02420-9185 Web: http://www.ll.mit.edu/CST/ MIT LL Root CA: <https://www.ll.mit.edu/labcertificateauthority.html> ----- Original Message ----- From: Yoav Nir [mailto:ynir.ietf@gmail.com] Sent: Monday, April 13, 2015 05:57 PM To: Geoffrey Keating <geoffk@geoffk.org> Cc: <tls@ietf.org> <tls@ietf.org> Subject: Re: [TLS] Ala Carte Cipher suites - was: DSA should die > On Apr 14, 2015, at 12:09 AM, Geoffrey Keating <geoffk@geoffk.org> wrote: > > Martin Thomson <martin.thomson@gmail.com> writes: > >> On 3 April 2015 at 17:05, Brian Smith <brian@briansmith.org> wrote: >>> I don't think the current mechanism is problematic >>> enough (at all, really) to justify that effort. >> >> I think that I've the same view. >> >> Then you have to consider interaction problems where some >> implementations have hardware for certain things, and software for >> others. Not only does that produce strong preferences for some things >> over others, it also can lead to holes in support tables, making a la >> carte selection tricky. >> >> That was always the clincher for me. > > I agree. In particular I don't think we've simplified anything if > implementations have to have a list of invalid combinations, or have > to know that certain ciphers are to be used only with matching key > exchange algorithms (for example, use the GOST key exchange with the > GOST symmetric cipher). Why? There’s nothing invalid about using Curve25519 key exchange with an RSA certificate and GOST symmetric ciphers, so TLS should not provide this. Requiring all three things to be GOST is a policy decision that can and should be part of server (and perhaps client) configuration. If some standard in Russia demands that GOST algorithms be used for all three, that should be configurable on the server. If OTOH the Russian authorities decide that they are fine with ECDHE for key exchange, but demand the GOST symmetric ciphers and authentication, that is also easy to get working with a la carte, but now it’s impossible until someone specifies such ciphersuites in a new document. Unless some combination creates an insecurity when each of its components is secure when combined with other components, I don’t think we have an issue. Yoav _______________________________________________ TLS mailing list TLS@ietf.org https://www.ietf.org/mailman/listinfo/tls
- Re: [TLS] DSA should die Yoav Nir
- Re: [TLS] DSA should die Dave Garrett
- [TLS] DSA should die Hanno Böck
- Re: [TLS] DSA should die Aaron Zauner
- Re: [TLS] DSA should die David Benjamin
- Re: [TLS] DSA should die Stephen Checkoway
- Re: [TLS] DSA should die Tony Arcieri
- Re: [TLS] DSA should die Bill Frantz
- Re: [TLS] DSA should die Tom Ritter
- Re: [TLS] DSA should die Viktor Dukhovni
- Re: [TLS] DSA should die Stephen Farrell
- Re: [TLS] DSA should die Nico Williams
- Re: [TLS] DSA should die Stephen Farrell
- Re: [TLS] DSA should die Viktor Dukhovni
- Re: [TLS] DSA should die Dave Garrett
- Re: [TLS] DSA should die Martin Thomson
- Re: [TLS] DSA should die Nico Williams
- Re: [TLS] DSA should die Martin Rex
- Re: [TLS] DSA should die Watson Ladd
- Re: [TLS] DSA should die Nico Williams
- Re: [TLS] DSA should die CodesInChaos
- Re: [TLS] DSA should die Martin Thomson
- Re: [TLS] DSA should die Dave Garrett
- Re: [TLS] DSA should die Nico Williams
- Re: [TLS] DSA should die Ilari Liusvaara
- Re: [TLS] DSA should die Joseph Salowey
- Re: [TLS] DSA should die Kurt Roeckx
- Re: [TLS] DSA should die Michael StJohns
- Re: [TLS] Ala Carte Cipher suites - was: DSA shou… Michael StJohns
- Re: [TLS] Ala Carte Cipher suites - was: DSA shou… Brian Smith
- Re: [TLS] Ala Carte Cipher suites - was: DSA shou… Tony Arcieri
- Re: [TLS] Ala Carte Cipher suites - was: DSA shou… Martin Thomson
- Re: [TLS] Ala Carte Cipher suites - was: DSA shou… Dave Garrett
- Re: [TLS] Ala Carte Cipher suites - was: DSA shou… Aaron Zauner
- Re: [TLS] Ala Carte Cipher suites - was: DSA shou… Dave Garrett
- Re: [TLS] Ala Carte Cipher suites - was: DSA shou… Viktor Dukhovni
- Re: [TLS] Ala Carte Cipher suites - was: DSA shou… Salz, Rich
- Re: [TLS] Ala Carte Cipher suites - was: DSA shou… Tony Arcieri
- Re: [TLS] Ala Carte Cipher suites - was: DSA shou… Yoav Nir
- Re: [TLS] Ala Carte Cipher suites - was: DSA shou… Brian Smith
- Re: [TLS] Ala Carte Cipher suites - was: DSA shou… Tony Arcieri
- Re: [TLS] Ala Carte Cipher suites - was: DSA shou… Ilari Liusvaara
- Re: [TLS] Ala Carte Cipher suites - was: DSA shou… Brian Sniffen
- Re: [TLS] Ala Carte Cipher suites - was: DSA shou… Viktor Dukhovni
- Re: [TLS] Ala Carte Cipher suites - was: DSA shou… Viktor Dukhovni
- Re: [TLS] Negotiate only symmetric cipher via cip… Dave Garrett
- Re: [TLS] Negotiate only symmetric cipher via cip… Daniel Kahn Gillmor
- Re: [TLS] Ala Carte Cipher suites - was: DSA shou… Aaron Zauner
- Re: [TLS] Negotiate only symmetric cipher via cip… Dave Garrett
- Re: [TLS] Negotiate only symmetric cipher via cip… Daniel Kahn Gillmor
- Re: [TLS] Negotiate only symmetric cipher via cip… Dave Garrett
- Re: [TLS] Negotiate only symmetric cipher via cip… Daniel Kahn Gillmor
- Re: [TLS] Negotiate only symmetric cipher via cip… Andrei Popov
- Re: [TLS] Negotiate only symmetric cipher via cip… Blumenthal, Uri - 0553 - MITLL
- Re: [TLS] Negotiate only symmetric cipher via cip… Viktor Dukhovni
- Re: [TLS] Negotiate only symmetric cipher via cip… Dave Garrett
- Re: [TLS] Negotiate only symmetric cipher via cip… Daniel Kahn Gillmor
- Re: [TLS] Negotiate only symmetric cipher via cip… Ilari Liusvaara
- Re: [TLS] Negotiate only symmetric cipher via cip… Dmitry Belyavsky
- Re: [TLS] Negotiate only symmetric cipher via cip… Daniel Kahn Gillmor
- Re: [TLS] Ala Carte Cipher suites - was: DSA shou… Geoffrey Keating
- Re: [TLS] Ala Carte Cipher suites - was: DSA shou… Yoav Nir
- Re: [TLS] Ala Carte Cipher suites - was: DSA shou… Viktor Dukhovni
- Re: [TLS] Ala Carte Cipher suites - was: DSA shou… Blumenthal, Uri - 0553 - MITLL
- Re: [TLS] Ala Carte Cipher suites - was: DSA shou… Geoffrey Keating
- Re: [TLS] Ala Carte Cipher suites - was: DSA shou… Viktor Dukhovni
- Re: [TLS] Ala Carte Cipher suites - was: DSA shou… Brian Smith
- Re: [TLS] Ala Carte Cipher suites - was: DSA shou… Brian Smith
- Re: [TLS] Ala Carte Cipher suites - was: DSA shou… Daniel Kahn Gillmor
- Re: [TLS] Ala Carte Cipher suites - was: DSA shou… Salz, Rich
- Re: [TLS] Ala Carte Cipher suites - was: DSA shou… Viktor Dukhovni
- Re: [TLS] Ala Carte Cipher suites - was: DSA shou… Dave Garrett
- Re: [TLS] Negotiate only symmetric cipher via cip… Ilari Liusvaara
- Re: [TLS] Ala Carte Cipher suites - was: DSA shou… Yoav Nir