Path: utzoo!attcan!uunet!tut.cis.ohio-state.edu!zaphod.mps.ohio-state.edu!uwm.edu!cs.utexas.edu!execu!sequoia!attdso!ssc!markz
From: markz@ssc.UUCP (Mark Zenier)
Newsgroups: sci.electronics
Subject: Re: 2764 UVEPROM.
Message-ID: <512@ssc.UUCP>
Date: 27 Feb 90 19:23:25 GMT
References: <2446@loral.UUCP>
Organization: SSC, Inc., Seattle, WA
Lines: 23

In article <2446@loral.UUCP>, miller@loral.UUCP (BIG DAVE) writes:
> Does anyone know a way of protecting the data that's been stored in a 2764, 
> 8KX8, EPROM ?. Is there a way of safegarding data stored in such devices 
> once one gives the device to someone else ?. I read the spec sheets and found
>no provisions for 'security bits', ala PALs, so I'm curious as to how one might
> get around to solving such a problem. I would greately appreciate any help in
> this matter.

If you want a portable source of protected data, you could try the
Dallas Semiconductor  DS5000 (if it exists yet).  It's a 8051 with
a battery backup ram (8k or 32K bytes), with a decrypter in the program
fetch.

"When activated, the device loads and executes the software in an encrypted
form, rendering the contents of the RAM and the execution of the program
unintelligible to the outside observer. ... Any attempt to discover the key
value results in its erasure, rendering the contents of the Program/Data
RAM useless."

The datasheet is marked Preliminary, so I don't know if its real yet.
Its the most paranoid part I've seen on the commercial market.

markz@ssc.uucp