Re: Quantum Ecomomics
Perry E. Metzger (perry@piermont.com)
Tue, 19 Mar 1996 23:05:05 -0500
"A. Padgett Peterson P.E. Information Security" writes:
[Lots of stuff that I disagree with, but I thought I'd mention one
concrete thing]
> Finally, no effort was made to determine when a solution was found. True
> most cryptographers assume "known plaintext". Fine except good mail
> systems use a different key for every message. If every message (or
> a good proportion always started the same way, fine. If not, welllllll.
I realize that the techniques may not be familiar to all, but simple
statistics on the decoded block make it pretty trivial to determine
whether or not it has been turned into plaintext. I believe the
technique has been described in detail by David Wagner (possibly with
Steve Bellovin, who he was working for at the time). I would describe
it in detail, but its pretty trivial to figure out about twenty ways
to do this, actually.
Breaking 40 bit RC4 or RC2 isn't a challenge, Mr. Peterson. If they
were even more widely deployed than they are now, it would be even
less of one, because unscrupulous companies would be producing
machines to do it in bulk. 40 bits is fake security, and I don't
believe in selling snake oil except to people with rusty snakes.
Perry