[Cryptography] Security of a permute-only system?

[Jonathan Thornburg]

On Wed, Nov 25, 2015 at 03:34:15PM -0800, Henry Baker wrote:
> Given a message source that's already "whitened", but otherwise unencrypted, how much security can be achieved strictly through an unknown, but random permutation?
> 
> I.e., if n=171, then a random permutation of size n would appear to require 1026 bits to specify it.
> 
> Suppose we simply applied our random permutation to each block of 171 pre-whitened bits.

Wouldn't this be vulnerable to multiple-anagraming attacks whenever we
have known (or even just recognizable) plaintext spanning multiple blocks?

ciao,

-- 
-- "Jonathan Thornburg [remove -animal to reply]" <jthorn at astro.indiana-zebra.edu>
   Dept of Astronomy & IUCSS, Indiana University, Bloomington, Indiana, USA
   "There was of course no way of knowing whether you were being watched
    at any given moment.  How often, or on what system, the Thought Police
    plugged in on any individual wire was guesswork.  It was even conceivable
    that they watched everybody all the time."  -- George Orwell, "1984"