From: jim bell <jimbell@pacifier.com>
Date: Fri, 15 Mar 1996 12:10:21 +0800
To: cypherpunks@toad.com
Subject: Re:LACC: PC Phones Home?
Message-ID: <m0txN0U-00094xC@pacifier.com>
MIME-Version: 1.0
Content-Type: text/plain


At 07:41 PM 3/13/96 -0800, Jim McCoy wrote:
>Dennis Hilliard writes:
>>
>>"Software to the rescue:
>>If somoeone steals your PC, you may be able to get it back because of
>>software that acts as a kind of tracking device. Home Office Computing
>>magazine reports that the software CompuTrace TRS will automatically dial
>>the office of its creator, Absolute Software, if a thief hooks up a stolen
>>PC's modem to a phone line. The software reveals the location of the PC and
>>Absolute Software will call the police" - Providence Journal-Bulletin -
>>March 12, 1996.

>1- How does the PC know where it is?
>2- How does the PC know it has been stolen?
>
>Since this is a software product I am assuming that the answer to #1
>is the use of CallerID on the line when the software calls, which is
>defeated by the use of line blocking by the thief. 

I think that 1-800 services provide caller ID information to the company or 
organization that pays for the service.  Whether or not this is blocked by 
standard caller-ID I don't know.   Nevertheless, like you, I am not 
impressed with the likelihood of success of this system.

> The obvious answer
>to #2 seems to me to have the system call the CompuTrace office at
>odd intervals to see if it has been reported stolen yet...

One thing that might be useful would be a OTP (one-time programmable) EPROM 
chip installed on all major system components (monitor, HD, motherboard, 
CDROM drive, maybe even DRAM SIMMs).  It would be a serial device for low 
cost, such as a 3-pin TO-92 chip, which would have a capacity of about 4k 
bits, enough to store a hash of the owner-history (at about 100 bits per 
owner) for any owner that decided to leave a record. Like an EPROM, bits 
could only be written once; the chip itself would prevent write-overs 
previous to the last-written bit. 

Subsequent owners could read the history and publish the hash codes; anyone 
looking for such a stolen product could have their losses checked 
automatically, and perhaps semi-anonymously or anonymously, by a service set 
up to do this.  Innocent owners could be adequately compensated for finding 
a piece of stolen hardware, to the extent that nobody is deterred about 
reporting a find.

Jim Bell
jimbell@pacifier.com