changing NSEC3 salt

[Klaus Darilion]

On 06.02.2014 14:58, Cathy Almond wrote:
> On 06/02/2014 12:58, Timothe Litt wrote:
>> On 06-Feb-14 05:56, Cathy Almond wrote:
>>> On 05/02/2014 18:54, David Newman wrote:
>>>> The Michael W. Lucas DNSSEC book recommends changing NSEC3 salt every
>>>> time a zone's ZSK changes.
>>>>
>>>> Is this just a matter of a new 'rndc signing' command, or is some action
>>>> needed to remove the old salt?
>>>>
>>>> thanks
>>>>
>>>> dn
>>> rndc signing -nsec3param ...
>>>
>>> I would expect the old NSEC3 chain and old NSEC3PARAM record to be
>>> removed, once the new chain is in place.
>>>
>>> (Similarly, the new NSEC3PARAM record will not appear in the zone until
>>> the new NSEC3 chain has been completely generated).
>>>
>>> Cathy
>>>
>> This seems silly.  Why should a person have to select a salt at all?
>> It's just a random number, and people are really bad at picking random
>> numbers.  Seems like a miss in 'DNSSEC for humans' :-)
>>
>> There should be a mechanism to tell named to pick a random number and
>> use it for the salt.  (I suggest '*' - '-' already means 'none'.)  named
>> already has to know how to get random numbers, so this should not be
>> difficult.  It should work for records supplied in UPDATE transactions
>> as well as rndc signing.
>>
>> A bit more work to have it function when loaded from a zone file, though
>> that doesn't seem unreasonable.  (E.g. if read from a zone file, pick a
>> salt, treat the record as if loaded with that value, and do all the
>> requisite (re-)signing.)
>>
>> I'm copying bind9-bugs so this doesn't get lost.  Please don't copy that
>> list if you comment on this. (Careful with that 'reply all'!)
>>
>> Timothe Litt
>> ACM Distinguished Engineer
>
> Sounds like a good idea - thanks.

Indeed. It would also solve the theoretical problem of NSEC3 hash 
collisions (see my email from 3. Feb 2014)

regards
Klaus