Re: Triple DES 192-bit key from shorter md5 hash value

From: Andreas Augustine (AndreasAugustine_at_discussions.microsoft.com)
Date: 10/07/04 

Date: Thu, 7 Oct 2004 09:49:34 -0700

Thx alot tlviewer:-)
I'v been searching for an answer for hours but still hadnt found this list
in google...I really appreciated the answer!
Now I have a good point to start from!
/Andreas

"tlviewer" wrote:

>
> "Andreas Augustine" <AndreasAugustine@discussions.microsoft.com> wrote in message news:7F64E2A0-B2D8-459C-8C99-9ED3BB827313@microsoft.com...
> > Hi, I'm trying to figure how "Microsoft Enhanced Cryptographic Provider"
> > generates a 192-bit session key from a md5 hashvalue (128-bits). Is there
> > anyone knows how its done?
> >
> > When I use ordinary DES with a md5hash as key it uses the first 8 bytes,
> > when I'm using DES3_128 it uses the whole 16 bytes...but what does it do
> > when using the full 192-bit DES3.
> >
> > I guess I could generate the full key myself but it would be interesting to
> > know how its done by default by Microsoft.
> >
> > Thx!
> > /Andreas
>
> This is an FAQ!
>
> see this list of links
> http://groups.google.com/groups?q=microsoft+3des+key+derivation&hl=en
>
> FYI -- the AES key derivation function is the same. IOW the newer crypto providers
> in Win 2003 are still using the 3DES KDF. I have verified it on WinXP pro too.
>
> hth,
> tlviewer
>

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