[49014] in Cypherpunks

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Re: RC2 technical questions

daemon@ATHENA.MIT.EDU (Mutatis Mutantdis)
Fri Feb 2 15:51:47 1996

From: wlkngowl@unix.asb.com (Mutatis Mutantdis)
To: cypherpunks@toad.com
Date: Fri, 02 Feb 1996 20:48:42 GMT

On Fri, 02 Feb 96 10:02:37 PST, "baldwin@RSA.COM" wrote:

>        In a shameless attempt to move the discussion of RC2 into
>a more technical arena, here are some interesting questions to
>explore about RC2.
>                --Bob

Odd. You're from RSA.COM... It would seem that you're better able to
find these things out than the rest of us.

Make that Alleged RC2, BTW. ;)

I'm rather curious about implementing known plaintext attacks.  The
reliance on addition and anding doesn't make me feel too confident.

For example, the ciphertext produced by the input of all zeros
(plaintext) is basically the added/anded (with rolls) skey bytes.

With a bit of probabilistic analysis one could work at determining the
skey[] bytes.  Weaknesses in the key expansion may help this
further...

Rob.



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