Re: [Cfrg] Security proofs v DH backdoors
Ilari Liusvaara <ilariliusvaara@welho.com> Tue, 25 October 2016 13:30 UTC
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Date: Tue, 25 Oct 2016 16:30:17 +0300
From: Ilari Liusvaara <ilariliusvaara@welho.com>
To: Dan Brown <danibrown@blackberry.com>
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Cc: CFRG <cfrg@irtf.org>
Subject: Re: [Cfrg] Security proofs v DH backdoors
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On Tue, Oct 25, 2016 at 01:10:16PM +0000, Dan Brown wrote: > How do the 3 recent IACR eprints on FFDH backdoors reconcile with > past security proofs for TLS, SSH, etc? > > Some guesses: (1) the attacks are outside the security definitions > (=> attacks not so important?), (2) the proofs assume strong FFDH > groups plus validation, etc. I guess the proofs assume strong FFDH groups, such that dlog and dh attacks are infeasible. I think there was one TLS implementation that tries to verify the groups sent (of course, not all can be verified, even if those aren't maliscously constructed). And the backdoors in one of the papers was about constructing prime such that one can use faster special case for dlogs. That can't be easily discovered, even if one somehow can obtain the group order. So one can't validate against it. -Ilari
- [Cfrg] Security proofs v DH backdoors Dan Brown
- Re: [Cfrg] Security proofs v DH backdoors Ilari Liusvaara
- Re: [Cfrg] Security proofs v DH backdoors Hanno Böck
- Re: [Cfrg] Security proofs v DH backdoors Peter Gutmann
- Re: [Cfrg] Security proofs v DH backdoors Mark D. Baushke
- Re: [Cfrg] Security proofs v DH backdoors Dan Brown
- Re: [Cfrg] Security proofs v DH backdoors Hanno Böck
- Re: [Cfrg] Security proofs v DH backdoors Daniel Bleichenbacher
- Re: [Cfrg] Security proofs v DH backdoors John Mattsson
- Re: [Cfrg] Security proofs v DH backdoors Dan Brown
- Re: [Cfrg] Security proofs v DH backdoors Peter Gutmann
- Re: [Cfrg] Security proofs v DH backdoors Hanno Böck
- Re: [Cfrg] Security proofs v DH backdoors Michael Scott
- Re: [Cfrg] Security proofs v DH backdoors Peter Gutmann
- Re: [Cfrg] Security proofs v DH backdoors Hanno Böck
- Re: [Cfrg] Security proofs v DH backdoors Ilari Liusvaara
- Re: [Cfrg] Security proofs v DH backdoors Peter Gutmann
- Re: [Cfrg] Security proofs v DH backdoors Peter Gutmann
- Re: [Cfrg] Security proofs v DH backdoors Peter Gutmann
- Re: [Cfrg] Security proofs v DH backdoors Ilari Liusvaara
- Re: [Cfrg] Security proofs v DH backdoors Ilari Liusvaara
- Re: [Cfrg] Security proofs v DH backdoors Salz, Rich
- Re: [Cfrg] Security proofs v DH backdoors Michael Scott
- Re: [Cfrg] Security proofs v DH backdoors Tony Arcieri
- Re: [Cfrg] Security proofs v DH backdoors Hanno Böck
- Re: [Cfrg] Security proofs v DH backdoors Tony Arcieri
- Re: [Cfrg] Security proofs v DH backdoors David Adrian
- Re: [Cfrg] Security proofs v DH backdoors Watson Ladd
- Re: [Cfrg] Security proofs v DH backdoors Peter Gutmann
- Re: [Cfrg] Security proofs v DH backdoors Antonio Sanso
- Re: [Cfrg] Security proofs v DH backdoors Peter Gutmann
- Re: [Cfrg] Security proofs v DH backdoors Peter Gutmann
- Re: [Cfrg] Security proofs v DH backdoors Peter Gutmann
- Re: [Cfrg] Security proofs v DH backdoors Peter Gutmann
- Re: [Cfrg] Security proofs v DH backdoors Hanno Böck
- Re: [Cfrg] Security proofs v DH backdoors Tony Arcieri
- Re: [Cfrg] Security proofs v DH backdoors Peter Gutmann
- Re: [Cfrg] Security proofs v DH backdoors Tony Arcieri
- Re: [Cfrg] Security proofs v DH backdoors Peter Gutmann
- Re: [Cfrg] Security proofs v DH backdoors Watson Ladd
- Re: [Cfrg] Security proofs v DH backdoors Peter Gutmann
- Re: [Cfrg] Security proofs v DH backdoors Paterson, Kenny
- Re: [Cfrg] Security proofs v DH backdoors Paterson, Kenny