Re: [dane] I-D Action: draft-ietf-dane-smime-03.txt
Viktor Dukhovni <viktor1dane@dukhovni.org> Fri, 07 February 2014 01:48 UTC
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Date: Fri, 07 Feb 2014 01:48:09 +0000
From: Viktor Dukhovni <viktor1dane@dukhovni.org>
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References: <41938fd202ba460285b59132c29ac826@BY2PR09MB029.namprd09.prod.outlook.com> <20140206195322.GD278@mournblade.imrryr.org> <11698F58-B554-4CC8-872F-D2A3BF08986C@kirei.se> <20140206215742.GF278@mournblade.imrryr.org> <07a801cf23a1$a5b62c00$f1228400$@augustcellars.com>
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Subject: Re: [dane] I-D Action: draft-ietf-dane-smime-03.txt
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On Thu, Feb 06, 2014 at 05:12:18PM -0800, Jim Schaad wrote: > A trivial way to avoid the global dictionary is to simply hash the email > address - that is both the local part and the domain. This would make it > unique for each domain. This also works, but is twice as fast as HMAC, where as my concern is that even HMAC is too fast. Of course a factor of 2 is not a real deterrent. So I must admit that there is no compelling reason to prefer HMAC over SHA2-224, provided the hash covers the domain. Perhaps I should mention the fact that in order to perform the off-line dictionary attack the attacker first has to discover a large fraction of the domain's NSEC3 records (assuming the domain does not provide NSEC records) and then dictionary attack the NSEC3 RRs. Thus he at least has to perform multiple NSEC3 hash iterations (far too few sadly to prevent off-line discovery of the most common user names). The iteration counts for NSEC3 are additive with respect to any iterations we might impose on the SMIMEA lookup key, rather than multiplicative because at any given time for a given zone all NSEC3 RRs have the same salt, and thus for each guess at a user name it is easy to compute the SMIMEA query domain, and thus the corresponding NSEC3 value for the current zone salt. -- Viktor.
- [dane] I-D Action: draft-ietf-dane-smime-03.txt internet-drafts
- Re: [dane] I-D Action: draft-ietf-dane-smime-03.t… Scott Rose
- Re: [dane] I-D Action: draft-ietf-dane-smime-03.t… Paul Hoffman
- Re: [dane] I-D Action: draft-ietf-dane-smime-03.t… Scott Rose
- Re: [dane] I-D Action: draft-ietf-dane-smime-03.t… Scott Rose
- Re: [dane] I-D Action: draft-ietf-dane-smime-03.t… Osterweil, Eric
- Re: [dane] I-D Action: draft-ietf-dane-smime-03.t… Jakob Schlyter
- Re: [dane] I-D Action: draft-ietf-dane-smime-03.t… Osterweil, Eric
- Re: [dane] I-D Action: draft-ietf-dane-smime-03.t… Viktor Dukhovni
- [dane] draft-ietf-dane-smime and certificate disc… Paul Hoffman
- Re: [dane] draft-ietf-dane-smime and certificate … Osterweil, Eric
- Re: [dane] I-D Action: draft-ietf-dane-smime-03.t… Osterweil, Eric
- Re: [dane] I-D Action: draft-ietf-dane-smime-03.t… Viktor Dukhovni
- Re: [dane] draft-ietf-dane-smime and certificate … Paul Hoffman
- Re: [dane] draft-ietf-dane-smime and certificate … Viktor Dukhovni
- Re: [dane] draft-ietf-dane-smime and certificate … Paul Hoffman
- Re: [dane] draft-ietf-dane-smime and certificate … Viktor Dukhovni
- Re: [dane] draft-ietf-dane-smime and certificate … Paul Hoffman
- Re: [dane] draft-ietf-dane-smime and certificate … Osterweil, Eric
- Re: [dane] draft-ietf-dane-smime and certificate … Osterweil, Eric
- Re: [dane] I-D Action: draft-ietf-dane-smime-03.t… Osterweil, Eric
- Re: [dane] I-D Action: draft-ietf-dane-smime-03.t… Viktor Dukhovni
- Re: [dane] I-D Action: draft-ietf-dane-smime-03.t… Paul Wouters
- Re: [dane] I-D Action: draft-ietf-dane-smime-03.t… Andrew Sullivan
- Re: [dane] I-D Action: draft-ietf-dane-smime-03.t… Viktor Dukhovni
- Re: [dane] I-D Action: draft-ietf-dane-smime-03.t… Andrew Sullivan
- Re: [dane] I-D Action: draft-ietf-dane-smime-03.t… Viktor Dukhovni
- Re: [dane] I-D Action: draft-ietf-dane-smime-03.t… Mark Andrews
- Re: [dane] I-D Action: draft-ietf-dane-smime-03.t… Mark Andrews
- Re: [dane] I-D Action: draft-ietf-dane-smime-03.t… Viktor Dukhovni
- Re: [dane] I-D Action: draft-ietf-dane-smime-03.t… Larsen, Todd
- Re: [dane] I-D Action: draft-ietf-dane-smime-03.t… Viktor Dukhovni
- Re: [dane] I-D Action: draft-ietf-dane-smime-03.t… Osterweil, Eric
- Re: [dane] I-D Action: draft-ietf-dane-smime-03.t… Larsen, Todd
- Re: [dane] I-D Action: draft-ietf-dane-smime-03.t… Viktor Dukhovni
- Re: [dane] I-D Action: draft-ietf-dane-smime-03.t… Osterweil, Eric
- Re: [dane] I-D Action: draft-ietf-dane-smime-03.t… Viktor Dukhovni
- Re: [dane] I-D Action: draft-ietf-dane-smime-03.t… Jakob Schlyter
- Re: [dane] I-D Action: draft-ietf-dane-smime-03.t… Viktor Dukhovni
- Re: [dane] I-D Action: draft-ietf-dane-smime-03.t… Jim Schaad
- [dane] Feature creep for draft-ietf-dane-smime Paul Hoffman
- Re: [dane] I-D Action: draft-ietf-dane-smime-03.t… Viktor Dukhovni
- Re: [dane] Feature creep for draft-ietf-dane-smime Viktor Dukhovni
- Re: [dane] I-D Action: draft-ietf-dane-smime-03.t… Wiley, Glen
- Re: [dane] Feature creep for draft-ietf-dane-smime Tom Ritter
- Re: [dane] I-D Action: draft-ietf-dane-smime-03.t… Paul Wouters
- Re: [dane] Feature creep for draft-ietf-dane-smime Paul Wouters
- Re: [dane] I-D Action: draft-ietf-dane-smime-03.t… Viktor Dukhovni
- Re: [dane] Feature creep for draft-ietf-dane-smime Viktor Dukhovni
- Re: [dane] Feature creep for draft-ietf-dane-smime Paul Hoffman
- Re: [dane] Feature creep for draft-ietf-dane-smime Viktor Dukhovni
- Re: [dane] Feature creep for draft-ietf-dane-smime John Levine
- Re: [dane] I-D Action: draft-ietf-dane-smime-03.t… Paul Wouters
- Re: [dane] I-D Action: draft-ietf-dane-smime-03.t… Viktor Dukhovni
- Re: [dane] I-D Action: draft-ietf-dane-smime-03.t… Viktor Dukhovni
- Re: [dane] Feature creep for draft-ietf-dane-smime Osterweil, Eric
- Re: [dane] Feature creep for draft-ietf-dane-smime Viktor Dukhovni
- Re: [dane] Feature creep for draft-ietf-dane-smime Warren Kumari
- Re: [dane] draft-ietf-dane-smime and certificate … Wes Hardaker