Re: [TLS] OPTLS: Signature-less TLS 1.3
Manuel Pégourié-Gonnard <mpg@polarssl.org> Sat, 01 November 2014 23:43 UTC
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Date: Sun, 02 Nov 2014 00:43:31 +0100
From: Manuel Pégourié-Gonnard <mpg@polarssl.org>
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To: Eric Rescorla <ekr@rtfm.com>, Watson Ladd <watsonbladd@gmail.com>
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Cc: "tls@ietf.org" <tls@ietf.org>, Hoeteck Wee <hoeteck@alum.mit.edu>
Subject: Re: [TLS] OPTLS: Signature-less TLS 1.3
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On 02/11/2014 00:22, Eric Rescorla wrote: > On Sat, Nov 1, 2014 at 3:22 PM, Watson Ladd <watsonbladd@gmail.com> wrote: >> Why does the duration of the validity of >> the response affect the existence of this issue? >> > > My argument here is that clients have some ability to sanity check > network time information, and so it's not necessarily like the attacker > can set the time to anything (I don't know how NTP clients currently > work). So an attacker who can only move the clock by a day or > two is going to of course be more effective attacking credentials > with a short time window than with a long time window > (though arguably that's because the latter is less secure to start > out with). > > Does that make sense? > I think it does, at least partially I'm by no means an expert on NTP security, but in my small experience, I've seen configurations on laptops where the NTP server is started when a network connection is established, and with an option that abruptly sets the time (rather than slowly shifting it) on startup (that's the -s option to openntpd for example). So, while I tend to agree that in theory clients could be able to sanity-check the network time if a precision of the order of days is desired, I'm afraid in practice it's not happening everywhere. But sure, needing a higher level of precision can only make more attacks practical in more circumstances. Manuel.
- Re: [TLS] OPTLS: Signature-less TLS 1.3 Rene Struik
- Re: [TLS] OPTLS: Signature-less TLS 1.3 Hugo Krawczyk
- Re: [TLS] OPTLS: Signature-less TLS 1.3 Rene Struik
- Re: [TLS] OPTLS: Signature-less TLS 1.3 Hugo Krawczyk
- [TLS] OPTLS: Signature-less TLS 1.3 Hugo Krawczyk
- Re: [TLS] OPTLS: Signature-less TLS 1.3 Eric Rescorla
- Re: [TLS] OPTLS: Signature-less TLS 1.3 Eric Rescorla
- Re: [TLS] OPTLS: Signature-less TLS 1.3 Watson Ladd
- Re: [TLS] OPTLS: Signature-less TLS 1.3 Nikos Mavrogiannopoulos
- Re: [TLS] OPTLS: Signature-less TLS 1.3 Ilari Liusvaara
- Re: [TLS] OPTLS: Signature-less TLS 1.3 Eric Rescorla
- Re: [TLS] OPTLS: Signature-less TLS 1.3 Watson Ladd
- Re: [TLS] OPTLS: Signature-less TLS 1.3 Eric Rescorla
- Re: [TLS] OPTLS: Signature-less TLS 1.3 Watson Ladd
- Re: [TLS] OPTLS: Signature-less TLS 1.3 Eric Rescorla
- Re: [TLS] OPTLS: Signature-less TLS 1.3 Manuel Pégourié-Gonnard
- Re: [TLS] OPTLS: Signature-less TLS 1.3 Watson Ladd
- Re: [TLS] OPTLS: Signature-less TLS 1.3 Hugo Krawczyk
- Re: [TLS] OPTLS: Signature-less TLS 1.3 Hugo Krawczyk
- Re: [TLS] OPTLS: Signature-less TLS 1.3 Hugo Krawczyk
- Re: [TLS] OPTLS: Signature-less TLS 1.3 Eric Rescorla
- Re: [TLS] OPTLS: Signature-less TLS 1.3 Eric Rescorla
- Re: [TLS] OPTLS: Signature-less TLS 1.3 Eric Rescorla
- Re: [TLS] OPTLS: Signature-less TLS 1.3 Nico Williams
- Re: [TLS] OPTLS: Signature-less TLS 1.3 Nico Williams
- Re: [TLS] OPTLS: Signature-less TLS 1.3 Hanno Böck
- Re: [TLS] OPTLS: Signature-less TLS 1.3 Peter Gutmann
- Re: [TLS] OPTLS: Signature-less TLS 1.3 Martin Thomson
- Re: [TLS] OPTLS: Signature-less TLS 1.3 Watson Ladd
- Re: [TLS] OPTLS: Signature-less TLS 1.3 Hugo Krawczyk
- Re: [TLS] OPTLS: Signature-less TLS 1.3 Hugo Krawczyk
- Re: [TLS] OPTLS: Signature-less TLS 1.3 Eric Rescorla
- Re: [TLS] OPTLS: Signature-less TLS 1.3 Hugo Krawczyk
- Re: [TLS] OPTLS: Signature-less TLS 1.3 Martin Thomson
- Re: [TLS] OPTLS: Signature-less TLS 1.3 Nico Williams
- Re: [TLS] OPTLS: Signature-less TLS 1.3 Watson Ladd
- Re: [TLS] OPTLS: Signature-less TLS 1.3 Nico Williams
- Re: [TLS] OPTLS: Signature-less TLS 1.3 Watson Ladd
- Re: [TLS] OPTLS: Signature-less TLS 1.3 Eric Rescorla
- Re: [TLS] OPTLS: Signature-less TLS 1.3 Hugo Krawczyk
- Re: [TLS] OPTLS: Signature-less TLS 1.3 Martin Thomson
- Re: [TLS] OPTLS: Signature-less TLS 1.3 Andy Lutomirski
- Re: [TLS] OPTLS: Signature-less TLS 1.3 Watson Ladd
- Re: [TLS] OPTLS: Signature-less TLS 1.3 Andy Lutomirski
- Re: [TLS] OPTLS: Signature-less TLS 1.3 Hugo Krawczyk
- Re: [TLS] OPTLS: Signature-less TLS 1.3 Daniel Kahn Gillmor
- Re: [TLS] OPTLS: Signature-less TLS 1.3 Daniel Kahn Gillmor
- Re: [TLS] OPTLS: Signature-less TLS 1.3 Martin Thomson
- Re: [TLS] OPTLS: Signature-less TLS 1.3 Daniel Kahn Gillmor
- Re: [TLS] OPTLS: Signature-less TLS 1.3 Martin Thomson
- Re: [TLS] OPTLS: Signature-less TLS 1.3 Watson Ladd
- Re: [TLS] OPTLS: Signature-less TLS 1.3 Eric Rescorla
- Re: [TLS] OPTLS: Signature-less TLS 1.3 Yoav Nir
- Re: [TLS] OPTLS: Signature-less TLS 1.3 Daniel Kahn Gillmor
- Re: [TLS] OPTLS: Signature-less TLS 1.3 Nico Williams
- Re: [TLS] OPTLS: Signature-less TLS 1.3 Nico Williams
- Re: [TLS] OPTLS: Signature-less TLS 1.3 Nico Williams
- Re: [TLS] OPTLS: Signature-less TLS 1.3 Yoav Nir
- Re: [TLS] OPTLS: Signature-less TLS 1.3 Nico Williams
- Re: [TLS] OPTLS: Signature-less TLS 1.3 Watson Ladd
- Re: [TLS] OPTLS: Signature-less TLS 1.3 Daniel Kahn Gillmor
- Re: [TLS] OPTLS: Signature-less TLS 1.3 Hugo Krawczyk
- Re: [TLS] OPTLS: Signature-less TLS 1.3 Watson Ladd
- Re: [TLS] OPTLS: Signature-less TLS 1.3 Nico Williams
- Re: [TLS] OPTLS: Signature-less TLS 1.3 Nico Williams
- Re: [TLS] OPTLS: Signature-less TLS 1.3 Nico Williams
- Re: [TLS] OPTLS: Signature-less TLS 1.3 Yoav Nir
- Re: [TLS] OPTLS: Signature-less TLS 1.3 Nico Williams
- Re: [TLS] OPTLS: Signature-less TLS 1.3 Hugo Krawczyk
- Re: [TLS] OPTLS: Signature-less TLS 1.3 Watson Ladd
- Re: [TLS] OPTLS: Signature-less TLS 1.3 Hugo Krawczyk
- Re: [TLS] OPTLS: Signature-less TLS 1.3 Salz, Rich
- Re: [TLS] OPTLS: Signature-less TLS 1.3 Blumenthal, Uri - 0558 - MITLL
- Re: [TLS] OPTLS: Signature-less TLS 1.3 Hugo Krawczyk
- Re: [TLS] OPTLS: Signature-less TLS 1.3 Watson Ladd
- Re: [TLS] OPTLS: Signature-less TLS 1.3 Salz, Rich
- Re: [TLS] OPTLS: Signature-less TLS 1.3 Dan Brown
- Re: [TLS] OPTLS: Signature-less TLS 1.3 Hugo Krawczyk