From: pgut001@cs.auckland.ac.nz (Peter Gutmann)
Date: Mon, 25 Aug 1997 04:41:57 -0700 (PDT)
To: hvdl@sequent.com
Subject: Re:  CAST key size
Message-ID: <87250919812278@cs26.cs.auckland.ac.nz>
MIME-Version: 1.0
Content-Type: text/plain


>Just a quick question on the keysize of the CAST algorithm. According to
>the bible of Bruce,  CAST uses a 64 bit keysize, while  in the manual of
>PGP 5.0 (page 89), Phill states that CAST uses a 128 bit keysize...
>
>Am I missing something?
 
"CAST" isn't a particular algorithm, but a design process for creating 
algorithms.  The particular CAST instantiation used in PGP 5 is either 
CAST-128 or CAST5, depending on who you ask.  Other versions of CAST abound, 
including an earlier one used by MS for unknown purposes which had a 64-bit 
key, probably the one Bruce is referring to.
 
Peter.