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