Re: triple DES with different keys, is it 2E112 or 2E168 to break?

From: Mok-Kong Shen (mok-kong.shen_at_t-online.de)
Date: 06/16/04 

Date: Wed, 16 Jun 2004 22:51:30 +0200

Austin Lesea wrote:
[snip]
> So, if 3DES is not a group, then there is no guarantee that there exists
> an x1 and x2 such that f(x1)=f(x2) so it is 2E168 (3 times 56 = 168, not
> 156).

The meaning of group property of a block cipher is explained in
HAC. If one applies that meaning to '3DES' (not DES), I don't
yet clearly see its connection to your equation. Could you
please reformulate your argumention in the notation of HAC?
(Sorry for troubling you due to my poor knowledge.)

M. K. Shen