Re: Carl Ellison on 'The Death of DES'

[m5@vail.tivoli.com (Mike McNally)]

 > Carl Ellison says:
 > > 3.	in between DES operations, mix bytes up as with	tran (posted on
 > > 	sci.crypt occasionally, avbl from me by mail or on ripem.msu.edu)
 > > 	-- spreading bytes out within a huge block, further hiding any
 > > 	known text

Can someone comment on the efficacy of this technique when used in
conjunction with encryption modes other than ECB, and/or with the
simple XOR "pre-scramble" technique?  I agree that it "couldn't hurt",
security-wise, but of course it does introduce a (slight) processing
overhead.  If it introduces no real additional security, I don't see
the point.  (Enlighten me!)

(This for some reason reminds me of the way little kids tie shoes;
they sometimes make enormous knots which, ultimately, are weaker than
a simple bow.)

--
Mike McNally