trusting the processor chip
jim bell
jimbell at pacifier.com
Fri Apr 26 20:05:56 PDT 1996
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.
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