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

["Paul Hoffman" <[e-mail]>]

On 26 Jul 2018, at 9:43, Ondřej Surý wrote:

>> On 26 Jul 2018, at 18:40, Wessels, Duane <[e-mail]> 
>> wrote:
>>
>> 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?
>
> That’s probably question you need to ask some cryptographer, so take 
> my opinion with a grain of salt.
>
> If <n> is the number of ZONEMD-covered records, then the probability 
> of collision attack gets higher.  So, unless
> I am mistaken, the delegation heavy zones would be especially 
> susceptible to a collision attack.  Does it make
> sense?

If the ZONEMD record is signed, the only person who can mount a 
collision attack is the zone owner themselves. If the ZONEMD record is 
unsigned, an attacker can just remove it.

What is the attack you are envisioning?

--Paul Hoffman