From: Eric Hughes <hughes@soda.berkeley.edu>
Date: Tue, 1 Jun 93 10:46:28 PDT
To: cypherpunks@toad.com
Subject: Crypto anarchy in a VW? (not the bug)
In-Reply-To: <199306011712.AA08151@ccwf.cc.utexas.edu>
Message-ID: <9306011820.AA21028@soda.berkeley.edu>
MIME-Version: 1.0
Content-Type: text/plain


>   The actual file encryption/decryption
>must be done in hardware if you want to have any sort of speed at all.

Please, everyone who is working on this, remember.  You can't do hard
disk encryption in software on the host CPU.  Thanks to Jim for
reminding me to stress this.

>Lacking an available IDEA chip I will have to use
>DES (multi-pass or some other variant to get around the limits on DES
>keyspace) in order to get the necessary throughput on the disk.

DES hardware is already available and tested.  Use it.  Use a
triple-keyed EDE version of DES.  

Is someone selling a raw DES chip on an ISA card?  If so, use that so
that others don't have to hack together their own hardware.

>Such a system would not be completely secure but would provide some
>protection for files, which is more than they get now...

The keying material for the disk should not be one key for the whole
disk.  The keying material could easily be one key per track without
the keys growing too large.

Ideally this keying material would be held on a removable PCMCIA card
and would talk directly to the device encryptor hardware with a
protected channel.  That will have to wait.

Eric