Anonglish (was: Re: Authenticating Meat)

[Jamie Lawrence]

On Wed, 30 Apr 2003, Sunder wrote:

> According to Schneier doing this is a bad idea - (or so I recall from the
> A.P. book which I've not reread in quite a while - I may be wrong) if you
> use the same (or similar) cypher.  i.e.:

> blowfish(blowfish(plaintext,key1),key2) is bad, 

I believe it doesn't gain you anything, but it isn't "bad" in the sense
of weakening anything.

If it were, analysts would start off by encrypting the message again.

It has been a while since I've read on this, too, so please correct me
if I'm wrong, but what is important for multiple encryption is whether
or not the cypher in question is a group (as in closed under
composition).

DES, for example, is not, so multiple DES cycles is not equivalent to
single DES.

Again, I probably shouldn't be talking about this, as I haven't
refreshed my memory on it in a while.



-j


-- 
Jamie Lawrence                                        jal at jal.org
"The current pursuit of American supremacy reminds me of the 
 the boom-bust process, or a stock market bubble. Whatever the 
 outcome in Iraq, I dare to predict that the Bush policies are 
 bound to fail."
   - George Soros