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The following archive was created by hippie-mail 7.98617-22 on Fri Aug 21 1998 - 17:16:16 ADT
Aaron D. Gifford (agifford@infowest.com)
Thu, 26 Mar 1998 05:38:28 +0000
Ron Rivest wrote:
>
> FYI:
> the revised version of my "chaffing and winnowing" paper
> http://theory.lcs.mit.edu/~rivest/chaffing.txt
> contains a more efficient implmentation, in the sense that you can
> have packets with large amounts of information per packet...
>
> Cheers,
> Ron Rivest
I like it!
Using the packaging technique described, the only caveat would seem to
be choosing a chaffing packet size correctly such that the total number
of packets sent is large enough to prevent brute-force unpackaging. If
C is the number of chaff packets generated for each wheat packet, and N
is the total number of wheat packets that the "packaged" message will be
broken up into to be sent, then brute-force unpackaging would require
testing probably half of (C+1)^N possible packages for a valid package
message. And one or more false messages could be packaged in the chaff
as well to further confuse the brute-force unpackging attempt.
This does make me wonder: Are there particular packaging techniques that
resist such a brute-force unpackaging search by eating more CPU cycles
versus a weaker technique that might have a weakness that permits a
brute-force unpackaging attempt to discard certiain packet combinations
with fewer CPU cycles? Are there any good pointers on the web for
packaging techniques? What would a good anti-brute-force (C+1)^N number
be to use as a lower limit in a chaffing implementation?
Thanks for the pointers in advance!
Aaron out.
The following archive was created by hippie-mail 7.98617-22 on Fri Aug 21 1998 - 17:16:16 ADT