CDR: Permutations in DES
Augusto Jun Devegili
devegili at inf.ufsc.br
Tue Sep 5 16:55:50 PDT 2000
Hi all,
I was just wondering... In DES, there's an Initial
Permutation (IP) on the plaintext, then 16 rounds, and
then the inverse permutation (IP^-1) of the result to
produce the ciphertext.
How effective are these permutations? Do they really
add diffusion to the algorithm, considering that they
don't depend on the key?
Someone told me that they are necessary to provide
reversibility to DES. Is this correct?
Thanks in advance,
Best Regards,
Devegili
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