Hi Marcelo!

<snip>

>> (2)  CGA implementations must not accept two different meanings of
>> the same Sec value as this would introduce a possibility for
>> downgrading attacks.  Specifically, an attacker may be able to find
>> a set of CGA parameters that produces a victim's CGA with a
>> cryptographically weak algorithm, while the victim itself has
>> previously generated the CGA with a cryptographically stronger
>> algorithm.
> 
> fully agree with this, however, not sure if we should include this in
>  the draft
> 
> i mean, we have discussed this point while writing this version of
> the draft and our conclusion was that an implementation that would do
> this would be really bogus so it was not worth mentioning it in the
> draft... i mean, i am not sure we need to describe how people should
> not shoot themselves in the foot in various ways...

Good point.  Maybe the security considerations is a better place to
discuss this.  The security considerations should in any case discuss
the issue of downbidding attacks IMO---basically saying that no
downbidding threat exists---, so it could be briefly mentioned there
that the inability to pursue a downbidding attack hinges on
implementations not accepting two different meanings of the same Sec value.

>> (3)  Optimally, new CGA implementations should include an interface
>> via which they can be updated to registry changes.  But since such
>> changes are expected to occur only at a very low frequency, it may
>> just be sufficient to pre-configure CGA implementations.
> 
> i am not sure i understand this... i mean reassigning the Sec value 
> would result in a different implementation i.e. additional code for
> the new hash function and so on, so i guess that more that a change
> in the registry will be needed, but actual code is needed in the
> stack.

I see your point.  That's correct.

<snip>

Take care,
- Christian

-- 
Christian Vogt, Institute of Telematics, Universitaet Karlsruhe (TH)
www.tm.uka.de/~chvogt/pubkey/


_______________________________________________
Int-area mailing list
[email protected]
https://www1.ietf.org/mailman/listinfo/int-area

Reply via email to