[80060] in Cypherpunks
Re: The War is Underway (fwd)
daemon@ATHENA.MIT.EDU (David Wagner)
Wed May 14 19:29:43 1997
To: cypherpunks@cyberpass.net
From: daw@cs.berkeley.edu (David Wagner)
Date: 14 May 1997 15:34:14 -0700
Reply-To: daw@cs.berkeley.edu (David Wagner)
In article <3.0.32.19970513223226.0074e2bc@netcom13.netcom.com>,
Lucky Green <shamrock@netcom.com> wrote:
> Contrast this with DESX, which has been
> proven to be twice as hard as DES, therefore having an effective keylength
> of 112 bits.
Actually, that's not true. Check out the Rogaway/Kilian paper.
It says that, if you've got 2^p known plaintexts, DESX has an effective
keylength of at least 118-p bits. So, for instance, if you've got 2^32
known plaintexts, DESX only has an effective keylength of 86 bits.
In short, 3DES is (roughly speaking) stronger than DESX.
