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With all of the discussion of C&W, and potential expansion, along with
a sideband discussion of same, I decided to ask 'the man' himself.
The '10K email file' used in the example came from the sideband discussion.
Forwarded for your edification.
------- Start of forwarded message -------
Date: Tue, 12 May 1998 18:24:46 -0400
From: Ron Rivest <[email protected]>
Subject: Chaffing question
Suppose you can start with a 10KB email file.
Running a package (all-or-nothing) transform on it adds only a small
amount to the length---say 128 bits total, or less (basically the length
of a key in your favorite algorithm).
You can break the result into 128 one-bit blocks and one 10KB block. MAC
each block.
Add 128 bits of chaff, intermingled with the first 128 blocks from above.
The final result has 128+128+1 packets, and total length 10KB (the
original email) + 257*64 bits (for the 257 64-bit MAC values) plus 128
bits (the chaff bits), and assuming that the sequence numbers are
implicit rather than explicit, you get a total of around 12.3 KB.
Cheers,
Ron
------- End of forwarded message -------
--
Jim Thompson / Smallworks, Inc. / [email protected]
512 338 0619 phone / 512 338 0625 fax
Real, cheap Hardware RNG: http://www.fringeware.com/nscd/