Why Twofish implementation only with 256 bit ?

David Shaw dshaw@jabberwocky.com
Sat May 3 17:11:02 2003


-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1

On Sat, May 03, 2003 at 02:46:02PM +0200, Malte Gell wrote:

> one of the common capabilities of all AES candidates was to offer 
> different key length, e.g. 128,192,256 bit. So one can edit his key in 
> order to make use of AES256 instead of "standard" 128 bit AES.
> 
> Why is this not the case with Twofish ? If I look at cipher.h it seems 
> 128 bit Twofish is deprecated and only experimental and the cipher 
> option "Twofish" always refers to 256 bit Twofish, so why is there no 
> Twofish/Twofish192/Twofish256 just as it is the case with Rijndael ?

The reason is the OpenPGP standard.  "Twofish", in RFC-2440, is
specified as 256-bit.

David
-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1.3.2-cvs (GNU/Linux)
Comment: http://www.jabberwocky.com/david/keys.asc

iD8DBQE+s9xC4mZch0nhy8kRAjOjAKCiC9/16rbrD5Pp7mc60FPrRkaqWwCgr+Wd
dJFT3tw/MoI/3bi5j6RcoA4=
=7S4T
-----END PGP SIGNATURE-----