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The following archive was created by hippie-mail 7.98617-22 on Sat Apr 10 1999 - 01:18:02
Ge' Weijers (ge@Progressive-Systems.Com)
Mon, 11 Jan 1999 12:48:31 -0500
On Fri, Jan 08, 1999 at 01:53:54PM +1000, Greg Rose wrote:
> I'm looking for any existing block ciphers with short (2 and 4 byte) block
> sizes. ISTR something going past me a few months ago on this subject, but
> can't remember where it was.
>
You would not be able to use this block cipher in any standard modes,
unless you have only a short block to encrypt. A 2-byte block cipher in
CBC mode would show duplicate values in the output after O(sqrt(2^16))
blocks, i.e. O(256), which is not that much. After that you have to
change the key. A way out would be to use a pseudo-random function in
CFB mode.
Ge'
-- - Ge' Weijers Voice: (614)326 4600 Progressive Systems, Inc. FAX: (614)326 4601 2000 West Henderson Rd. Suite 400, Columbus OH 43220
The following archive was created by hippie-mail 7.98617-22 on Sat Apr 10 1999 - 01:18:02