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Re: [dnsext] DS digest downgrade

Francis Dupont <Francis.Dupont@fdupont.fr> Tue, 22 March 2011 15:50 UTC

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From: Francis Dupont <Francis.Dupont@fdupont.fr>
To: Derek Atkins <warlord@MIT.EDU>
In-reply-to: Your message of Tue, 22 Mar 2011 09:00:36 -0400. <sjmipvbcnt7.fsf@pgpdev.ihtfp.org>
Date: Tue, 22 Mar 2011 16:51:42 +0100
Sender: Francis.Dupont@fdupont.fr
Cc: dnsext@ietf.org
Subject: Re: [dnsext] DS digest downgrade
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 In your previous mail you wrote:

   It also doesn't help protect against an active man-in-the-middle who can
   make sure that the validator never receives the SHA256 DS RR.

=> if the DS RRset is signed this is not possible.

   Unfortunately the validator can only validate what it receives; there's
   often not a way for it to know what it should expect to receive.
   
=> this opens the door to DoS attacks but as far as I know
no more.

Regards

Francis.Dupont@fdupont.fr

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