Re: [DNSOP] New Version Notification for draft-wessels-dns-zone-digest-01.txt

["Wessels, Duane" <[e-mail]>]

Ondrej,

Thanks, I think thats a fair point.  I was of course hoping to not create yet another IANA registry.

If the ZONEMD RR included a count of records as suggested by Paul Wouters would you then be comfortable
just using the DS hash algorithms?

DW


> On Jul 25, 2018, at 8:47 PM, Ondřej Surý <[e-mail]> wrote:
> 
> Hi Matt, and other authors,
> 
> with my cryptoplumber[1] hat, I am strongly opposed to using SHA-1 and GOST R 34.11-94 for ZONEMD.
> 
> It is my understanding, that the specific usage of hashing function in the DS record improves the collision
> resistance of the algorithm, because the input data is so small and it has to be a valid DNSKEY record[2].
> 
> For ZONEMD, this isn’t true, as you can (in theory) feed the zone with infinite amount of non-DNSSEC-signed
> data (GLUEs, delegations) thus making the collision attack feasible.
> 
> Thus I believe, the Section 2.1.2 must be changed to disallow usage of algorithms with weakened collision
> resistance (and algorithms deprecated by the Russians themselves :). It wouldn’t be enough just to discourage
> SHA-1 for creating the ZONEMD, but it needs to be forbidden to use it for validating such record.
> I think that new IANA table for ZONEMD must be established, because the security properties of the algorithm
> usage are different in DS and ZONEMD records.
> 
> Thanks,
> Ondrej
> 
> 1. I would be happy if any real cryptographer would chime in.
> 
> 2. It doesn’t have to be valid DNSKEY if you just want to cause ruckus, but if you are able to inject invalid DS
>    records, you might as well cause damage at other levels of the DNS tree.
> 
> --
> Ondřej Surý
> [e-mail]
> 
>> On 23 May 2018, at 17:32, Weinberg, Matt <mweinberg=[e-mail]> wrote:
>> 
>> Greetings dnsop,
>> 
>> We’ve posted a new version of draft-wessels-dns-zone-digest.  Of note, this -01 version includes the following changes:
>> 
>> 	• Warren Kumari and Wes Hardaker have been added as coauthors.
>> 	• Several points of clarification in wording and descriptions.
>> 	• Removed the requirement to sort by RR CLASS.
>> 	• Added a Change Log section.
>> 
>> Warren and Wes had started on a very similar but unpublished draft, which we should've remembered.  Thanks to them for agreeing to join this document as coauthors.
>> We plan to ask for time on the dnsop agenda in Montreal.  Your feedback is welcome and appreciated.    
>> 
>> Thanks.
>> 
>> ----
>> 
>>   A new version of I-D, draft-wessels-dns-zone-digest-01.txt
>>   has been successfully submitted by Matt Weinberg and posted to the
>>   IETF repository.
>> 
>>   Name:		draft-wessels-dns-zone-digest
>>   Revision:	01
>>   Title:		Message Digest for DNS Zones
>>   Document date:	2018-05-17
>>   Group:		Individual Submission
>>   Pages:		13
>>   URL:            https://www.ietf.org/internet-drafts/draft-wessels-dns-zone-digest-01.txt
>>   Status:         https://datatracker.ietf.org/doc/draft-wessels-dns-zone-digest/
>>   Htmlized:       https://tools.ietf.org/html/draft-wessels-dns-zone-digest-01
>>   Htmlized:       https://datatracker.ietf.org/doc/html/draft-wessels-dns-zone-digest
>>   Diff:           https://www.ietf.org/rfcdiff?url2=draft-wessels-dns-zone-digest-01
>> 
>>   Abstract:
>>      This document describes a protocol and DNS Resource Record used to
>>      provide a message digest over DNS zone data.  In particular, it
>>      describes how to compute, sign, represent, and use the message digest
>>      to verify the contents of a zone for accuracy and completeness.  The
>>      ZONEMD Resource Record type is introduced for conveying the message
>>      digest data.
>> 
>> 
>> 
>> 
>>   Please note that it may take a couple of minutes from the time of submission
>>   until the htmlized version and diff are available at tools.ietf.org.
>> 
>>   The IETF Secretariat
>> 
>> 
>> 
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