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Re: [sidr] preventing SKI collisions

Tim Bruijnzeels <tim@ripe.net> Fri, 07 August 2015 11:59 UTC

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From: Tim Bruijnzeels <tim@ripe.net>
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Subject: Re: [sidr] preventing SKI collisions
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> On Aug 7, 2015, at 11:35 AM, Randy Bush <randy@psg.com> wrote:
> 
>> This change would require certificates to be re-issued (or possibly
>> keys to be rolled) all the way down from Trust Anchors. When the
>> parent CA re-issues a certificate for the child CA with a new style
>> SKI, then the child will have to re-issue its products with a new AKI.
>> 
>> This is not impossible, but not trivial either. Especially if a
>> delegated model is used.
> 
> have we done a dnssec-v1?  we should be able to change hashes without a
> flag day.  if not, we need to think.

actually, thinking about this a bit longer now..

If both SHA-1 and SHA-256 are allowed (at least for a while) this can be initiated by any CA that wants to make the change.

Important bits are:
 - RFC6492 uses SKIs for revoke requests
 - The AKI of products issued by a CA should match their SKI

I guess that the easiest way to make this work is a key roll. Create a new key, request a certificate for it with the new SKI, re-issue the products with the new key, and finally revoke the old key (using the old style SKI).

It's still work, but not as bad as I previously painted.

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