RE: [Ipsec] Rekeying IKE_SAs with the CREATE_CHILD_SA exhange

> Pasi.Eronen@nokia.com writes:
> > My interpretation of the spec is that
> >  
> >   - When you're rekeying the IKE_SA, and you're not doing D-H,
> >     the KEi/KEr payloads are not included.
> > 
> > But at least Tero and Paul disagreed with this conclusion back
> > in April (i.e., you have to include a dummy KEi/KEr payloads
> > even when you're not doing D-H --- but only the IKE_SA case,
> > not in the CHILD_SA case)...
> 
> Not dummy KEi/KEr payloads. I say that the Diffie-Hellman is mandatory
> when you rekey IKE_SA. There is no point of doing IKE SA rekey if you
> do not do Diffie-Hellman at the same time, as that means that breaking
> the original IKE SA protection will also reveal these keys.
> 
> There is reasons to do IPsec SA rekeys without doing the
> Diffie-Hellman, but I do not think any of those reasons apply for the
> IKE SA.

I agree with both. I think that if DiffieHellman exchange is not
mandatory when rekeying an IKE_SA, then if one doesn't want to perform
that exchange he shouldn't include any KE payload. 
I also agree with Tero: there isn't any reason (IMHO) to make an IKE_SA
rekey without a DiffieHellman exchange.

-- 
Alejandro Perez Mendez <alejandro_perez@dif.um.es>

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