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Re: Clarification on 3DES transforms
In message <199610250050.UAA02112@thunk.orchard.medford.ma.us>, Bill Sommerfeld writes:
> > DES_Key_I = Truncate(MD5( D_Pad_I | K ),192)
> > DES_KEY_I1 = first 64 bits of DES_KEY_I
> > DES_KEY_I2 = second 64 bits of DES_KEY_I
> > DES_KEY_I3 = third 64 bits of DES_KEY_I
>
> MD5 only produces 128 bits of output, so this is not going to work
> very well ...
I've seen specs that say:
DES_Key_I = MD5(D_Pad_I | K)
DES_KEY_1 = first 64 bits of DES_KEY_I
DES_KEY_2 = second (and last) 64 bits of DES_KEY_I
DES_Key_II = MD5(D_Pad_I | K | K);
DES_KEY_3 = first 64 bits of DES_Key_II
Same question; how do the Real Cryptographers feel about this one?
--
C. Harald Koch | Senior System Developer, Secure Computing Canada Ltd.
chk@border.com | 20 Toronto Street, Suite 400, Toronto ON M5C 2B8
+1 416 368 7157 (voice) | "Madness takes its toll. Please have exact change."
+1 416 368 7789 (fax) | -Karen Murphy <karenm@descartes.com>
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