Re: [dane] Digest Algorithm Agility discussion
Mark Andrews <marka@isc.org> Sun, 23 March 2014 23:01 UTC
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To: dane@ietf.org
From: Mark Andrews <marka@isc.org>
References: <20140315051704.GY21390@mournblade.imrryr.org> <0l4n2sa5a0.fsf@wjh.hardakers.net> <20140322074737.GA5739@anguilla.noreply.org> <20140323174205.63C6111B2111@rock.dv.isc.org> <20140323182106.GX24183@mournblade.imrryr.org> <20140323185718.7A84711B2CB8@rock.dv.isc.org> <20140323191037.GA1469@anguilla.noreply.org> <20140323192557.7716111B342A@rock.dv.isc.org> <20140323200008.GB1469@anguilla.noreply.org> <20140323202831.GB13649@mournblade.imrryr.org>
In-reply-to: Your message of "Sun, 23 Mar 2014 20:28:31 -0000." <20140323202831.GB13649@mournblade.imrryr.org>
Date: Mon, 24 Mar 2014 10:01:25 +1100
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Subject: Re: [dane] Digest Algorithm Agility discussion
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In message <20140323202831.GB13649@mournblade.imrryr.org>, Viktor Dukhovni writ es: > On Sun, Mar 23, 2014 at 09:00:08PM +0100, Peter Palfrader wrote: > > > On Mon, 24 Mar 2014, Mark Andrews wrote: > > > > > > Site A only publishes SHA1 entries. Would rather do unauthenticated TL > S > > > > than trust SHA1? > > > > > > You left out - report and refuse to send until fixed. > > > > No, that's not what the SMTP draft suggests. When DANE is not there, > > then servers just fall back to not authenticating a peer's cert, as they > > do nowadays. The SMTP draft says how to securely go from a email domain to a CERT using DNSSEC and TLSA. It does not say whether one should use a non secure connection or not. That is seperate policy. > Indeed if one simply considers (again hypothetically) SHA1 to be > "unusable", then with no "usable" TLSA records, the connection > would fall back to unauthenticated TLS. It might or it might not. That is a seperate policy decision. > To do what Mark suggests, we'd have to treat SHA1 as usable, but > always fails. That is new code to make SHA1 never match. One will have something like if (!supported(match)) skip record; > And > still I don't see anyone shooting themselves in the foot with > self-imposed flag days for a long time after an algorithm becomes > suspect. > > I sees that, the unstated objection must be a belief that SHA2-256 > will never fail, and thus we're wasting time designing solutions > to a non-problem. While I don't believe in eternal unbounded > progress, and (barring a P=NP revolution) it is likely that at some > point we'll have algorithms that never need replacement, it is > perhaps premature to declare mission-complete with SHA2. I don't assume that it will never be broken. I also don't think we need to "if has_alg(a) then {} else {}". > For if we are to take the threat of gradual degradation of our > confidence in SHA2 seriously, we need usable approaches for phasing > it out. Flag days don't look like usable approaches to me. > > -- > Viktor. > > _______________________________________________ > dane mailing list > dane@ietf.org > https://www.ietf.org/mailman/listinfo/dane -- Mark Andrews, ISC 1 Seymour St., Dundas Valley, NSW 2117, Australia PHONE: +61 2 9871 4742 INTERNET: marka@isc.org
- [dane] Digest Algorithm Agility discussion Viktor Dukhovni
- Re: [dane] Digest Algorithm Agility discussion Paul Wouters
- Re: [dane] Digest Algorithm Agility discussion Viktor Dukhovni
- Re: [dane] Digest Algorithm Agility discussion Paul Hoffman
- Re: [dane] Digest Algorithm Agility discussion Paul Wouters
- Re: [dane] Digest Algorithm Agility discussion Viktor Dukhovni
- Re: [dane] Digest Algorithm Agility discussion Viktor Dukhovni
- Re: [dane] Digest Algorithm Agility discussion Paul Hoffman
- Re: [dane] Digest Algorithm Agility discussion Viktor Dukhovni
- Re: [dane] Digest Algorithm Agility discussion Paul Wouters
- Re: [dane] Digest Algorithm Agility discussion Viktor Dukhovni
- Re: [dane] Digest Algorithm Agility discussion Paul Hoffman
- Re: [dane] Digest Algorithm Agility discussion Viktor Dukhovni
- Re: [dane] Digest Algorithm Agility discussion Martin Rex
- Re: [dane] Digest Algorithm Agility discussion Viktor Dukhovni
- Re: [dane] Digest Algorithm Agility discussion Mark Andrews
- Re: [dane] Digest Algorithm Agility discussion Viktor Dukhovni
- Re: [dane] Digest Algorithm Agility discussion (c… Viktor Dukhovni
- Re: [dane] Digest Algorithm Agility discussion Jim Schaad
- Re: [dane] Digest Algorithm Agility discussion (c… Paul Hoffman
- Re: [dane] Digest Algorithm Agility discussion (c… Andrew Sullivan
- Re: [dane] Digest Algorithm Agility discussion (c… Viktor Dukhovni
- Re: [dane] Digest Algorithm Agility discussion (c… Scott Rose
- Re: [dane] Digest Algorithm Agility discussion (c… Viktor Dukhovni
- Re: [dane] Digest Algorithm Agility discussion (c… Scott Rose
- Re: [dane] Digest Algorithm Agility discussion Wes Hardaker
- Re: [dane] Digest Algorithm Agility discussion Viktor Dukhovni
- Re: [dane] Digest Algorithm Agility discussion Peter Palfrader
- Re: [dane] Digest Algorithm Agility discussion Mark Andrews
- Re: [dane] Digest Algorithm Agility discussion Viktor Dukhovni
- Re: [dane] Digest Algorithm Agility discussion Mark Andrews
- Re: [dane] Digest Algorithm Agility discussion Peter Palfrader
- Re: [dane] Digest Algorithm Agility discussion Mark Andrews
- Re: [dane] Digest Algorithm Agility discussion Viktor Dukhovni
- Re: [dane] Digest Algorithm Agility discussion Peter Palfrader
- Re: [dane] Digest Algorithm Agility discussion Viktor Dukhovni
- Re: [dane] Digest Algorithm Agility discussion Mark Andrews
- Re: [dane] Digest Algorithm Agility discussion Mark Andrews
- Re: [dane] Digest Algorithm Agility discussion Viktor Dukhovni
- Re: [dane] Digest Algorithm Agility discussion Paul Wouters
- Re: [dane] Digest Algorithm Agility discussion Viktor Dukhovni
- Re: [dane] Digest Algorithm Agility discussion Peter Palfrader
- Re: [dane] Digest Algorithm Agility discussion Wes Hardaker
- Re: [dane] Digest Algorithm Agility discussion Wes Hardaker