Re: [dane] case sensitivity and draft-ietf-dane-smime / draft-wouters-dane-openpgp
Paul Hoffman <paul.hoffman@vpnc.org> Tue, 10 September 2013 21:17 UTC
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From: Paul Hoffman <paul.hoffman@vpnc.org>
In-Reply-To: <alpine.LFD.2.10.1309101607020.4683@bofh.nohats.ca>
Date: Tue, 10 Sep 2013 17:16:51 -0400
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References: <alpine.LFD.2.10.1309091040120.14065@bofh.nohats.ca> <8A7BC0FC-62F8-4883-8FDD-948AAF9DAB78@vpnc.org> <alpine.LFD.2.10.1309101607020.4683@bofh.nohats.ca>
To: Paul Wouters <paul@cypherpunks.ca>
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Cc: dane WG list <dane@ietf.org>
Subject: Re: [dane] case sensitivity and draft-ietf-dane-smime / draft-wouters-dane-openpgp
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On Sep 10, 2013, at 4:09 PM, Paul Wouters <paul@cypherpunks.ca> wrote: > On Tue, 10 Sep 2013, Paul Hoffman wrote: > >> On Sep 9, 2013, at 10:52 AM, Paul Wouters <paul@cypherpunks.ca> wrote: >> >>> It was brought to my attention by Matthias Wimmer that we overlooked >>> an important issue with respect to the base32 generation of the base32 >>> encoded left hand side of the email address. >> >> "We" did not overlook that: as author, I made that decision completely purposefully. > > Perhaps documentation of that decision belonged in the Security Section > of that document? :) I'm not clear what the security consideration of this is for DANE outside of what it is for all RFC 821(+bis)(+bis)(+bis) email has been. >>> Mail servers and mail clients do not treat email addresses as >>> case-insensitive. >> >> That is sometimes-true statement. >> >>> When encoding an LHS with base32, the case matters. >> >> Yes, exactly. And so does internationalization. >> >>> Using the wrong case will cause you to not find the SMIMEA / OPENPGPKEY >>> record. >> >> Yep. And will cause you to sometimes send mail to the wrong recipient. > > I'm really not okay with a protocol where I encrypt to the wrong key > based on the case of the email address. Errr, then maybe you should not send mail with PGP or S/MIME? Seriously: this issue precedes DANE by well over a decade. >>> We should probably add a section explaining this, and perhaps suggest to >>> lowercase before base32'ing the LHS for the lookup. >> >> Yes; no. > [citation needed] We should add a note that case is preserved and that might be surprising; we should not suggest breaking RFC 821(+bis)(+bis)(+bis) in this protocol. --Paul Hoffman
- [dane] case sensitivity and draft-ietf-dane-smime… Paul Wouters
- Re: [dane] case sensitivity and draft-ietf-dane-s… Viktor Dukhovni
- Re: [dane] case sensitivity and draft-ietf-dane-s… Francis Dupont
- Re: [dane] case sensitivity and draft-ietf-dane-s… Jakob Schlyter
- Re: [dane] case sensitivity and draft-ietf-dane-s… Paul Wouters
- Re: [dane] case sensitivity and draft-ietf-dane-s… Peter Saint-Andre
- Re: [dane] case sensitivity and draft-ietf-dane-s… Olle E. Johansson
- Re: [dane] case sensitivity and draft-ietf-dane-s… Paul Hoffman
- Re: [dane] case sensitivity and draft-ietf-dane-s… Paul Wouters
- Re: [dane] case sensitivity and draft-ietf-dane-s… Dickson, Brian
- Re: [dane] case sensitivity and draft-ietf-dane-s… Paul Hoffman
- Re: [dane] case sensitivity and draft-ietf-dane-s… Martin Rex