Re: Modification on AES

On Fri, 25 Dec 2009 20:45:01 -0800, J.D. wrote:
That is true. But in addition to the s-box not being invertible/
decryptable if it is not a permutation, any n-by-n s-box that is not a
permutation will necessarily have some entries that are duplicates of
each other, opening the door to collision attacks.

Thanks. I didn't know that. After the s-box is generated, cycle through
the bytes, checking if they were used before. If they were, increase by 1
until an unused value is found.



--
"The beginning of knowledge is the discovery of something we do not
understand."-Frank Herbert
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