From: jim bell <jimbell@pacifier.com>
Date: Sat, 27 Apr 1996 11:05:56 +0800
To: Rick Smith <smith@sctc.com>
Subject: Re: trusting the processor chip
Message-ID: <m0uCrFs-0008y2C@pacifier.com>
MIME-Version: 1.0
Content-Type: text/plain


At 10:50 AM 4/26/96 -0500, Rick Smith wrote:
>Having penned the response to Jeffrey Flinn on the unlikelihood of
>processor back doors, I'll comment on jim bell's response:

>> More likely,I think, an organization like the NSA 
>>might build a pin-compatible version of an existing, commonly-used product 
>>like a keyboard encoder chip that is designed to transmit (by RFI signals) 
>>the contents of what is typed at the keyboard.  It's simple, it's hard to 
>>detect, and it gets what they want.
>
>Simple, no.

By NSA standards, it is simple.  NSA has probably had its own semiconductor 
fabs for 30+ years.  Even if we assume that their capabilities lag 
commercial production in terms of density or quality, keyboard encoder chips 
were trivial 20+ years ago and could presumably be easily 
duplicated/modified today by even the oldest operating fabs.  They probably 
had far less than 10,000 transistors.  Even modern keyboard controllers 
probably "waste"  a microcontroller with far more capability than you'd need 
for the task, and microcontrollers usually have substantially more code area 
than would be necessary to add some sort of surreptitious function.

>Hard to detect, somewhat.

You'd have to know what to look for.


>Gets what they want, unclear.

If there was one single data stream you'd like to get, it's the keyboard.  
This doesn't get you everything, but close.