Re: arcfour: hmac-md5 vs. md5

[Elrond]

On Wed, May 03, 2006 at 12:14:55PM +0200, Simon Josefsson wrote:
> Elrond <address@hidden> writes:
> 
> > Any news on this?
> >
> > Or are you just plain busy? :)
> 
> Busy weekend..  I haven't had time to look into this yet.  But solving
> this is my main priority for shishi, so hopefully I'll get to it very
> soon.

Ahh good. :)


> I have a vague memory that ARCFOUR-HMAC checksum was invented later
> than the ARCFOUR encryption scheme.  So it may be that w2k3 doesn't
> support it in the same way as shishi implement it.  If Heimdal doesn't
> use it against w2k3, maybe we shouldn't either.  But that doesn't
> really answer why things behave as they do for you below.

Looking at the subkey parameter test (previous mail), I
start to suspect, that the authenticator's checksum is
keyed using the subkey or something.

And I further guess, that heimdal (as shishi) just ignores
the subkey for most things.

Which one is "correct according to the specs":
You know the specs better than me.


    Elrond