Re: a DoS vulnerability associated with conflated Message-IDs?

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+Message-ID: <4F58E962.1050403@fifthhorseman.net>\r
+Date: Thu, 08 Mar 2012 12:16:18 -0500\r
+From: Daniel Kahn Gillmor <dkg@fifthhorseman.net>\r
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+To: James Vasile <james@hackervisions.org>\r
+Subject: Re: a DoS vulnerability associated with conflated Message-IDs?\r
+References: <87k42vrqve.fsf@pip.fifthhorseman.net>\r
+       <87ipif2fdn.fsf@wyzanski.jamesvasile.com>\r
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+\r
+On 03/08/2012 12:04 PM, James Vasile wrote:\r
+> On Thu, 08 Mar 2012 11:37:09 -0500, Daniel Kahn Gillmor<dkg@fifthhorseman.net>  wrote:\r
+>> Any ideas on how to approach this?\r
+>\r
+> Treat messages with the same ID but different hashes as different?\r
+\r
+Given that a message hash would include all headers, including Received: \r
+and other MTA-added stuff, i think that would remove all relevance of \r
+the Message-ID field. in particular, it seems like we would just be \r
+identifying messages by their digest.\r
+\r
+If you're willing to ignore the headers and just look at a digest of the \r
+body, that still doesn't provide any help for the common (legitimate) \r
+case of a message jointly-delivered to a mailing list and to a specific \r
+(already-subscribed) user.\r
+\r
+That user will get two copies of the message, and since most mailing \r
+lists modify the body of the message (usually by adding a footer section \r
+with mailing list info) their bodies will also have different digests.\r
+\r
+So i don't see how to make this suggestion work without giving up on \r
+Message-IDs as the identifier entirely (and therefore accepting many \r
+more spurious duplicates than users currently need to tolerate).\r
+\r
+Any other suggestions or ideas?\r
+\r
+       --dkg\r