Re: [ietf-822] A permission to re-sign header
Miles Fidelman <mfidelman@meetinghouse.net> Sun, 20 April 2014 00:00 UTC
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Date: Sat, 19 Apr 2014 20:00:05 -0400
From: Miles Fidelman <mfidelman@meetinghouse.net>
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Archived-At: http://mailarchive.ietf.org/arch/msg/ietf-822/mXCrJKkyRmECVoaa0yTat5Z0jV8
Subject: Re: [ietf-822] A permission to re-sign header
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Pete Resnick wrote: > On 4/19/14 10:52 AM, Theodore Ts'o wrote: > >> There are mailing lists that want to "fix" broken messages, yes, but >> if we need to provide end-to-end assurance that the message really >> came from the originator... > > Providing end-to-end assurance that the message really came from the > originator is not the stated goal. It would be nice if we could do > that, but so far there are operational and deployment problems with > accomplishing that. I've got ideas about how we might improve that > situation, but they will take much longer to deploy than the things we > are talking about here. > Is that not a critical goal? As a sender, I want to make sure that my message gets through intact (authentication and integrity). As a recipient, I want to know who authored the message (authentication) and that I got what the author sent (integrity). It strikes me that it's a secondary consideration as to whether the author intended to send the message to me - i.e., these cases seem important, but secondary: - someone uses the list as a vector to send unwanted traffic (e.g., spam) - that seems to be an issue for authentication of the author, to the list server - the list server sends stuff to me, even if I'm not on it (that's simply unsolicited email) - a malicious actor masquerades as a list server that I'm on - that's about the list server authenticating itself to recipients Ultimately, a sender cares about "protecting their name" (e.g., avoiding phishing attacks), and protecting the integrity of what they send. A recipient wants to have some assurance that what they're reading came from the avowed sender, and that what you're reading is what they sent. What that suggests to me is that: 1. The original sending system has to attach some strong cryptography to provide both authentication, and integrity. 2. Any intermediate system that munges pieces of the message (changing the From address, adding subject tags, adding message headers and footers) - has to ALSO add enough information that a recipient can recreate the original message, exactly, and validate the original signature. E.g., - if a mailing list changes the From: address, it has to put the original From: address in a Original-From: header - if a mailing list adds tags to the subject line, it has to put the original Subject: into an Original-Subject header - if a mailing list adds 5 lines of header and 5 lines of footer to the text body, then it needs to add a header indicating as much - with that information, software at the receiving end can recreate the original message, and check its authentication and integrity, and mistrust all of the modifications the mailing list added - the mailing list software can additionally add signatures to authenticate itself and provide integrity for the things its changed/added - of course things get a bit more complicated if MIME, or S/MIME, or PGP-enhanced mail, or digests, etc. are added to the mix - and, of course, this has to be done in a standard way - otherwise nobody will be able to write code Miles Fidelman -- In theory, there is no difference between theory and practice. In practice, there is. .... Yogi Berra
- [ietf-822] A permission to re-sign header John Levine
- Re: [ietf-822] A permission to re-sign header Alessandro Vesely
- Re: [ietf-822] A permission to re-sign header John Levine
- Re: [ietf-822] A permission to re-sign header Hector Santos
- Re: [ietf-822] A permission to re-sign header Murray S. Kucherawy
- Re: [ietf-822] A permission to re-sign header John R Levine
- Re: [ietf-822] A permission to re-sign header Murray S. Kucherawy
- Re: [ietf-822] A permission to re-sign header John R Levine
- Re: [ietf-822] A permission to re-sign header Pete Resnick
- Re: [ietf-822] A permission to re-sign header Pete Resnick
- Re: [ietf-822] A permission to re-sign header John R Levine
- Re: [ietf-822] A permission to re-sign header Pete Resnick
- Re: [ietf-822] A permission to re-sign header John R Levine
- Re: [ietf-822] A permission to re-sign header Alessandro Vesely
- Re: [ietf-822] A permission to re-sign header Michael Richardson
- Re: [ietf-822] A permission to re-sign header Michael Richardson
- Re: [ietf-822] A permission to re-sign header Theodore Ts'o
- Re: [ietf-822] A permission to re-sign header Pete Resnick
- Re: [ietf-822] A permission to re-sign header Miles Fidelman
- Re: [ietf-822] A permission to re-sign header John Levine
- Re: [ietf-822] one can re-sign without a permissi… Ned Freed
- Re: [ietf-822] one can re-sign without a permissi… Alessandro Vesely
- Re: [ietf-822] A permission to re-sign header Ned Freed
- Re: [ietf-822] A permission to re-sign header Alessandro Vesely
- Re: [ietf-822] A permission to re-sign header Paul Smith
- Re: [ietf-822] don't need a permission to re-sign… John Levine
- Re: [ietf-822] don't need a permission to re-sign… Ned Freed
- Re: [ietf-822] don't need a permission to re-sign… John R Levine
- Re: [ietf-822] don't need a permission to re-sign… Ned Freed
- Re: [ietf-822] one can re-sign without a permissi… Alessandro Vesely
- Re: [ietf-822] one can re-sign without a permissi… Ned Freed
- Re: [ietf-822] one can re-sign without a permissi… Pete Resnick
- Re: [ietf-822] one can re-sign without a permissi… Douglas Otis
- [ietf-822] We need a DKIM Policy Working Group Hector Santos
- Re: [ietf-822] We need a DKIM Policy Working Group S Moonesamy
- Re: [ietf-822] one can re-sign without a permissi… John Levine
- Re: [ietf-822] one can re-sign without a permissi… John Levine
- Re: [ietf-822] WSJ/gmail/ML, was a permission to.… Miles Fidelman
- Re: [ietf-822] WSJ/gmail/ML, was a permission to.… Alessandro Vesely
- Re: [ietf-822] one can re-sign without a permissi… Douglas Otis
- Re: [ietf-822] one can re-sign without a permissi… Pete Resnick
- Re: [ietf-822] one can re-sign without a permissi… Alessandro Vesely
- Re: [ietf-822] one can re-sign without a permissi… Paul Smith
- Re: [ietf-822] one can re-sign without a permissi… John R Levine
- Re: [ietf-822] one can re-sign without a permissi… Hector Santos
- Re: [ietf-822] one can re-sign without a permissi… Douglas Otis
- Re: [ietf-822] WSJ/gmail/ML, was a permission to.… Alessandro Vesely
- Re: [ietf-822] one can re-sign without a permissi… Hector Santos
- [ietf-822] WSJ/gmail/ML, was a permission to... Alessandro Vesely
- Re: [ietf-822] WSJ/gmail/ML, was a permission to.… John R Levine
- Re: [ietf-822] WSJ/gmail/ML, was a permission to.… Paul Smith
- Re: [ietf-822] WSJ/gmail/ML, was a permission to.… Rolf E. Sonneveld
- Re: [ietf-822] WSJ/gmail/ML, was a permission to.… Hector Santos
- Re: [ietf-822] WSJ/gmail/ML, was a permission to.… Michael Richardson
- Re: [ietf-822] WSJ/gmail/ML, was a permission to.… Paul Smith
- Re: [ietf-822] WSJ/gmail/ML, was a permission to.… Alessandro Vesely
- Re: [ietf-822] WSJ/gmail/ML, was a permission to.… Miles Fidelman
- Re: [ietf-822] WSJ/gmail/ML, was a permission to.… John R Levine
- Re: [ietf-822] WSJ/gmail/ML, was a permission to.… John Levine
- Re: [ietf-822] WSJ/gmail/ML, was a permission to.… Arnt Gulbrandsen
- Re: [ietf-822] WSJ/gmail/ML, was a permission to.… John Levine
- Re: [ietf-822] WSJ/gmail/ML, was a permission to.… Ned Freed
- Re: [ietf-822] WSJ/gmail/ML, was a permission to.… Dave Crocker
- Re: [ietf-822] WSJ/gmail/ML, was a permission to.… Ned Freed
- Re: [ietf-822] WSJ/gmail/ML, was a permission to.… John R Levine
- Re: [ietf-822] WSJ/gmail/ML, was a permission to.… John R Levine
- Re: [ietf-822] WSJ/gmail/ML, was a permission to.… Arnt Gulbrandsen
- Re: [ietf-822] WSJ/gmail/ML, was a permission to.… Bart Schaefer
- Re: [ietf-822] WSJ/gmail/ML, was a permission to.… Hector Santos
- Re: [ietf-822] WSJ/gmail/ML, was a permission to.… John Levine
- Re: [ietf-822] WSJ/gmail/ML, was a permission to.… Michael Richardson
- Re: [ietf-822] WSJ/gmail/ML, was a permission to.… Michael Richardson
- Re: [ietf-822] WSJ/gmail/ML, was a permission to.… John Levine
- Re: [ietf-822] WSJ/gmail/ML, was a permission to.… Ned Freed
- Re: [ietf-822] WSJ/gmail/ML, was a permission to.… Michael Richardson
- Re: [ietf-822] WSJ/gmail/ML, was a permission to.… Michael Richardson
- Re: [ietf-822] WSJ/gmail/ML, was a permission to.… Russ Allbery
- Re: [ietf-822] WSJ/gmail/ML, was a permission to.… Brandon Long
- Re: [ietf-822] WSJ/gmail/ML, was a permission to.… Brandon Long
- Re: [ietf-822] WSJ/gmail/ML, was a permission to.… Arnt Gulbrandsen
- Re: [ietf-822] WSJ/gmail/ML, was a permission to.… Alessandro Vesely
- Re: [ietf-822] one can re-sign without a permissi… Paul Smith
- Re: [ietf-822] WSJ/gmail/ML, was a permission to.… Hector Santos
- Re: [ietf-822] WSJ/gmail/ML, was a permission to.… John R Levine
- Re: [ietf-822] WSJ/gmail/ML, was a permission to.… Ned Freed
- Re: [ietf-822] WSJ/gmail/ML, was a permission to.… S Moonesamy
- Re: [ietf-822] WSJ/gmail/ML, was a permission to.… Russ Allbery
- Re: [ietf-822] WSJ/gmail/ML, was a permission to.… Hector Santos
- Re: [ietf-822] one can re-sign without a permissi… Brandon Long
- Re: [ietf-822] one can re-sign without a permissi… Murray S. Kucherawy
- Re: [ietf-822] WSJ/gmail/ML, was a permission to.… Miles Fidelman
- Re: [ietf-822] one can re-sign without a permissi… John R Levine
- Re: [ietf-822] WSJ/gmail/ML, was a permission to.… Ned Freed
- Re: [ietf-822] WSJ/gmail/ML, was a permission to.… S Moonesamy
- Re: [ietf-822] one can re-sign without a permissi… John Levine
- Re: [ietf-822] WSJ/gmail/ML, was a permission to.… Miles Fidelman
- Re: [ietf-822] WSJ/gmail/ML, was a permission to.… Scott Kitterman
- Re: [ietf-822] WSJ/gmail/ML, was a permission to.… Russ Allbery
- Re: [ietf-822] one can re-sign without a permissi… Murray S. Kucherawy
- Re: [ietf-822] one can re-sign without a permissi… John R Levine
- Re: [ietf-822] one can re-sign without a permissi… Hector Santos
- Re: [ietf-822] WSJ/gmail/ML, was a permission to.… S Moonesamy
- Re: [ietf-822] WSJ/gmail/ML, was a permission to.… Paul Smith
- Re: [ietf-822] WSJ/gmail/ML, was a permission to.… Alessandro Vesely
- Re: [ietf-822] WSJ/gmail/ML, was a permission to.… Miles Fidelman
- Re: [ietf-822] WSJ/gmail/ML, was a permission to.… John Levine
- Re: [ietf-822] WSJ/gmail/ML, was a permission to.… John Levine
- Re: [ietf-822] WSJ/gmail/ML, was a permission to.… Brandon Long
- Re: [ietf-822] WSJ/gmail/ML, was a permission to.… Brandon Long
- Re: [ietf-822] WSJ/gmail/ML, was a permission to.… Russ Allbery
- [ietf-822] Aptness of DKIM for MLs Alessandro Vesely
- Re: [ietf-822] WSJ/gmail/ML, was a permission to.… Alessandro Vesely
- Re: [ietf-822] Aptness of DKIM for MLs S Moonesamy
- Re: [ietf-822] Aptness of DKIM for MLs Alessandro Vesely
- Re: [ietf-822] Aptness of DKIM for MLs S Moonesamy
- Re: [ietf-822] Aptness of DKIM for MLs Hector Santos
- Re: [ietf-822] Aptness of DKIM for MLs Douglas Otis
- Re: [ietf-822] Aptness of DKIM for MLs Alessandro Vesely
- Re: [ietf-822] Aptness of DKIM for MLs Douglas Otis
- Re: [ietf-822] WSJ/gmail/ML, was a permission to.… Douglas Otis
- Re: [ietf-822] Aptness of DKIM for MLs Alessandro Vesely
- Re: [ietf-822] one can re-sign without a permissi… Douglas Otis