Re: [saag] AD review of draft-iab-crypto-alg-agility-06
Nico Williams <nico@cryptonector.com> Thu, 03 September 2015 22:18 UTC
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Date: Thu, 03 Sep 2015 17:18:56 -0500
From: Nico Williams <nico@cryptonector.com>
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References: <55A938F1.9090404@cs.tcd.ie> <20150720044849.GY28047@mournblade.imrryr.org> <B866063D-C1A8-4286-83E1-9EBAE7994297@vigilsec.com> <20150902212858.GM9021@mournblade.imrryr.org>
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Subject: Re: [saag] AD review of draft-iab-crypto-alg-agility-06
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Viktor asks me what the take-away from section 2.5 should be. IMO it is as follows. Applications (app devs) and users are not in a good position to evaluate cryptographic strength (and acceptability) of outcomes of protocol negotiations, therefore this should be moved to local policy. Local policy includes defaults provided by implementors of security mechanisms (TLS, Kerberos, etcetera). This I-D, aiming to be a BCP, needs to outline a best practice as to policy. That best practice, IMO, is to give application developers and users a very small control knob: a choice between named policies with simple semantics. "Strong", "normal", "opportunistic", "maximally interoperable", "weak" -- these are both, good names and descriptions of possible policies to apply; they are also good descriptors of outcomes. Local policy should be expressible in some way, but it's OK if it's hardcoded in implementations, as long as there are choices like the ones I listed above, as those are the ones that applications and their users need to apply. It's OK -expected!- that the content of such policies will vary over time because the relative strengths of cryptographic algorithms and protocols vary over time as cryptanalysis improves. Another take-away here is that implementors of security mechanisms and frameworks really must provide interfaces by which to request a policy to apply. I.e., SASL, GSS, and others need a way for the application to request a policy or check whether an outcome meets a given policy. It's not really enough to tell users to edit N configuration files, especially if that makes it difficult to have more than one policy. Now, local policy is NOT really part of a protocol. So, this guidance can't be for protocol designers. It can be for framework API designers (e.g., for us in KITTEN WG). It can be for implementors of protocols and frameworks. That's OK, we can do that in a BCP. Nico --
- [saag] AD review of draft-iab-crypto-alg-agility-… Stephen Farrell
- Re: [saag] AD review of draft-iab-crypto-alg-agil… Paul Hoffman
- Re: [saag] AD review of draft-iab-crypto-alg-agil… Black, David
- Re: [saag] AD review of draft-iab-crypto-alg-agil… Kathleen Moriarty
- Re: [saag] AD review of draft-iab-crypto-alg-agil… Eliot Lear
- Re: [saag] AD review of draft-iab-crypto-alg-agil… Derek Atkins
- Re: [saag] AD review of draft-iab-crypto-alg-agil… Watson Ladd
- Re: [saag] AD review of draft-iab-crypto-alg-agil… Viktor Dukhovni
- Re: [saag] AD review of draft-iab-crypto-alg-agil… ianG
- Re: [saag] AD review of draft-iab-crypto-alg-agil… Black, David
- Re: [saag] AD review of draft-iab-crypto-alg-agil… Black, David
- Re: [saag] AD review of draft-iab-crypto-alg-agil… Viktor Dukhovni
- Re: [saag] AD review of draft-iab-crypto-alg-agil… Viktor Dukhovni
- Re: [saag] AD review of draft-iab-crypto-alg-agil… Nico Williams
- Re: [saag] AD review of draft-iab-crypto-alg-agil… Stephen Farrell
- Re: [saag] AD review of draft-iab-crypto-alg-agil… Viktor Dukhovni
- Re: [saag] AD review of draft-iab-crypto-alg-agil… Nico Williams
- Re: [saag] AD review of draft-iab-crypto-alg-agil… Nico Williams
- Re: [saag] AD review of draft-iab-crypto-alg-agil… Viktor Dukhovni
- Re: [saag] AD review of draft-iab-crypto-alg-agil… Stephen Farrell
- Re: [saag] AD review of draft-iab-crypto-alg-agil… Nico Williams
- Re: [saag] AD review of draft-iab-crypto-alg-agil… Viktor Dukhovni
- Re: [saag] AD review of draft-iab-crypto-alg-agil… Stephen Farrell
- Re: [saag] AD review of draft-iab-crypto-alg-agil… Stephen Farrell
- Re: [saag] AD review of draft-iab-crypto-alg-agil… Nico Williams
- Re: [saag] AD review of draft-iab-crypto-alg-agil… Stephen Farrell
- Re: [saag] AD review of draft-iab-crypto-alg-agil… Salz, Rich
- Re: [saag] AD review of draft-iab-crypto-alg-agil… Nico Williams
- Re: [saag] AD review of draft-iab-crypto-alg-agil… ianG
- Re: [saag] AD review of draft-iab-crypto-alg-agil… Viktor Dukhovni
- Re: [saag] AD review of draft-iab-crypto-alg-agil… Christian Huitema
- Re: [saag] AD review of draft-iab-crypto-alg-agil… Viktor Dukhovni
- Re: [saag] AD review of draft-iab-crypto-alg-agil… Kathleen Moriarty
- Re: [saag] AD review of draft-iab-crypto-alg-agil… Martin Thomson
- Re: [saag] AD review of draft-iab-crypto-alg-agil… Viktor Dukhovni
- Re: [saag] AD review of draft-iab-crypto-alg-agil… Salz, Rich
- Re: [saag] AD review of draft-iab-crypto-alg-agil… Kathleen Moriarty
- Re: [saag] AD review of draft-iab-crypto-alg-agil… Salz, Rich
- Re: [saag] AD review of draft-iab-crypto-alg-agil… Stephen Farrell
- Re: [saag] AD review of draft-iab-crypto-alg-agil… Viktor Dukhovni
- Re: [saag] AD review of draft-iab-crypto-alg-agil… Viktor Dukhovni
- Re: [saag] AD review of draft-iab-crypto-alg-agil… Salz, Rich
- Re: [saag] AD review of draft-iab-crypto-alg-agil… David Misell
- Re: [saag] AD review of draft-iab-crypto-alg-agil… Peter Gutmann
- Re: [saag] AD review of draft-iab-crypto-alg-agil… Viktor Dukhovni
- Re: [saag] AD review of draft-iab-crypto-alg-agil… Peter Gutmann
- Re: [saag] AD review of draft-iab-crypto-alg-agil… Viktor Dukhovni
- Re: [saag] AD review of draft-iab-crypto-alg-agil… Peter Gutmann
- Re: [saag] AD review of draft-iab-crypto-alg-agil… Salz, Rich
- Re: [saag] AD review of draft-iab-crypto-alg-agil… Viktor Dukhovni
- Re: [saag] AD review of draft-iab-crypto-alg-agil… Stephen Farrell
- Re: [saag] AD review of draft-iab-crypto-alg-agil… Salz, Rich
- Re: [saag] AD review of draft-iab-crypto-alg-agil… Kathleen Moriarty
- Re: [saag] AD review of draft-iab-crypto-alg-agil… Viktor Dukhovni
- Re: [saag] AD review of draft-iab-crypto-alg-agil… Viktor Dukhovni
- Re: [saag] AD review of draft-iab-crypto-alg-agil… Kathleen Moriarty
- Re: [saag] AD review of draft-iab-crypto-alg-agil… Martin Thomson
- Re: [saag] AD review of draft-iab-crypto-alg-agil… Viktor Dukhovni
- Re: [saag] AD review of draft-iab-crypto-alg-agil… Viktor Dukhovni
- Re: [saag] AD review of draft-iab-crypto-alg-agil… Yoav Nir
- Re: [saag] AD review of draft-iab-crypto-alg-agil… Stephen Farrell
- Re: [saag] AD review of draft-iab-crypto-alg-agil… Paterson, Kenny
- Re: [saag] AD review of draft-iab-crypto-alg-agil… Nico Williams
- Re: [saag] AD review of draft-iab-crypto-alg-agil… Stephen Farrell
- Re: [saag] AD review of draft-iab-crypto-alg-agil… Stephen Farrell
- Re: [saag] AD review of draft-iab-crypto-alg-agil… Paterson, Kenny
- Re: [saag] AD review of draft-iab-crypto-alg-agil… Peter Gutmann
- Re: [saag] AD review of draft-iab-crypto-alg-agil… Eliot Lear
- Re: [saag] AD review of draft-iab-crypto-alg-agil… Viktor Dukhovni
- Re: [saag] AD review of draft-iab-crypto-alg-agil… Nico Williams
- Re: [saag] AD review of draft-iab-crypto-alg-agil… Derek Atkins
- Re: [saag] AD review of draft-iab-crypto-alg-agil… Martin Thomson
- Re: [saag] AD review of draft-iab-crypto-alg-agil… Watson Ladd
- Re: [saag] AD review of draft-iab-crypto-alg-agil… Viktor Dukhovni
- Re: [saag] AD review of draft-iab-crypto-alg-agil… Martin Thomson
- Re: [saag] AD review of draft-iab-crypto-alg-agil… Salz, Rich
- Re: [saag] AD review of draft-iab-crypto-alg-agil… Joel Sing
- Re: [saag] AD review of draft-iab-crypto-alg-agil… Viktor Dukhovni
- Re: [saag] AD review of draft-iab-crypto-alg-agil… Russ Housley
- Re: [saag] AD review of draft-iab-crypto-alg-agil… Russ Housley
- Re: [saag] AD review of draft-iab-crypto-alg-agil… Viktor Dukhovni
- Re: [saag] AD review of draft-iab-crypto-alg-agil… Viktor Dukhovni
- Re: [saag] AD review of draft-iab-crypto-alg-agil… Eliot Lear
- Re: [saag] AD review of draft-iab-crypto-alg-agil… Eliot Lear
- Re: [saag] AD review of draft-iab-crypto-alg-agil… Russ Housley
- Re: [saag] AD review of draft-iab-crypto-alg-agil… Eliot Lear
- Re: [saag] AD review of draft-iab-crypto-alg-agil… Viktor Dukhovni
- Re: [saag] AD review of draft-iab-crypto-alg-agil… Russ Housley
- Re: [saag] AD review of draft-iab-crypto-alg-agil… Russ Housley
- Re: [saag] AD review of draft-iab-crypto-alg-agil… Salz, Rich
- Re: [saag] AD review of draft-iab-crypto-alg-agil… Viktor Dukhovni
- Re: [saag] AD review of draft-iab-crypto-alg-agil… Salz, Rich
- Re: [saag] AD review of draft-iab-crypto-alg-agil… Nico Williams
- Re: [saag] AD review of draft-iab-crypto-alg-agil… Christian Huitema
- Re: [saag] AD review of draft-iab-crypto-alg-agil… Viktor Dukhovni
- Re: [saag] AD review of draft-iab-crypto-alg-agil… Watson Ladd
- Re: [saag] AD review of draft-iab-crypto-alg-agil… Nico Williams
- Re: [saag] AD review of draft-iab-crypto-alg-agil… Viktor Dukhovni
- Re: [saag] AD review of draft-iab-crypto-alg-agil… Derek Atkins
- Re: [saag] AD review of draft-iab-crypto-alg-agil… Russ Housley
- Re: [saag] AD review of draft-iab-crypto-alg-agil… Russ Housley
- Re: [saag] AD review of draft-iab-crypto-alg-agil… Viktor Dukhovni
- Re: [saag] AD review of draft-iab-crypto-alg-agil… Russ Housley