defending against evil in all layers of hardware and software

[Stephan Neuhaus]

On Apr 28, 2008, at 23:56, Perry E. Metzger wrote:

> If you have a rotten apple engineer, he will be able to hide what he's
> trying to do and make it look completely legit. If he's really good,
> it may not be possible to catch what he's done EVEN IN PRINCIPLE.

Fred Cohen proved in 1984 in his "Computer Viruses, Theory and  
Experiments"[1] that "Program P is a virus" is undecidable. I assume  
that this result can be applied to hardware in the form that "Chip C  
contains malicious gates" is also undecidable. (Caveat: Cohen seems to  
make the fundamental assumption that there is no fundamental  
distinction between code and data, something that need not necessarily  
hold everywhere inside a computer chip.)

Fun,

Stephan

[1] See for example http://vx.netlux.org/lib/afc01.html

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