Re: Blockcipher >256 bit (for hardware implementation)



Do you have a suggestion for me? What other blockcipher could I
consider?

Out of interest, why do you need a 340-bit block?

I would use AES if it is at all possible with the conventional 128-bit
block and 128-bit key.

The problem here is that you're probably going to pay either a security
penalty or speed penalty for demanding such a big block.

Nobody designs fast, secure block ciphers of this size. This is not
because its impossible to do it's just that kind of design isn't
needed.

It's likely that you can use some composite structure to get this block
size but that is likely to be slower than using a more standard
construction. It's probably too slow to be of use to you.

It might be tempting to design you own primitive. Don't do it! Use
something standard and you won't go wrong.

Simon

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