Re: [ietf-provreg] secdns draft

[Klaus Malorny <Klaus.Malorny@knipp.de>]

Edward Lewis wrote:

> At 18:49 +0200 10/25/05, Klaus Malorny wrote:
> 
> 
> To explain #2.  Imagine a registrant creates a key and the (DS data 
> representing the) key is sent to the registry.  If the registrant's 
> private key is then "stolen/guessed/exposed", the party that has gained 
> illegitimate access to the key can abuse the key as long as the DS 
> record is seen as valid.  So, shortening the DS record means the window 
> of vulnerability is lessened.
> 
> The TTL record value was also considered, but the DNSSEC specs (RFC 
> 4034, etc.) already specify the TTL value.
> 
>> related to the above:
>>
>> ** what should the registry do at the end of the lifetime?
> 
> 
> The lifetime is relative.  If there is no change, just regenerate the 
> signature over the DS record.  When to regenerate a signature is a 
> deeper topic - some suggest regenerating signatures about 1/2 way 
> through the lifetime just to be sure the signatures get out there in 
> time.  But never sign the DS set for more time than the prudent/agreed 
> upon lifetime duration.
> 

Thanks for the clarification. I thought the most simple solution to revoke a 
key is to remove it from the zone, as it would break the chain of trust also. 
But I have to admit that I am not yet fully aware of the effects of the various 
caching mechanisms on the time a resolver can falsely assume the correctness of 
a revoked key. I have to check that.

regards,

Klaus

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