http://cm.bell-labs.com/who/ken/trust.html Ken Thompson, creator of UNIX "You can't trust code that you did not totally create yourself." C compiler could put an invisible backdoor in the Unix login command when it noticed that the login program was being compiled C compiler could also add this feature undetectably to future compiler versions upon their compilation as well. "I picked on the C compiler. I could have picked on any program-handling program such as an assembler, a loader, or even hardware microcode. As the level of program gets lower, these bugs will be harder and harder to detect. A well installed microcode bug will be almost impossible to detect." "No amount of source-level verification or scrutiny will protect you from using untrusted code."
A source comparison would suffice. It is not necessary to identify every login program for the attack to be useful.
IHBT.
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Anonymous2013-06-26 2:04
How about "Hardware Backdoors in ICs Considered Harmful"?
"- You cannot trust hardware where you did not build all the logic gates yourself!"
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Anonymous2013-06-26 2:25
>>14
It's easy to reason the logic of IC. You put in some test input and the output should be as expected. If there is any discrepancy, that particular function is broken.
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Anonymous2013-06-26 2:36
>>15
What if there is some secret quantum hardware to compensate for that? What if the NSA has released a spore of nanobots that pick up or alter circuitry at runtime when very specific conditions are met? What if the entire universe is a simulation and the simulator will always present the proper output and input only when it detects that it is being observed? What if God decides to spy on you and alters the physical properties of the universe itself only in your circuit when you aren't testing it?
>>15
But when an IC has state it can pretend to be anything.
Also, assuming that two or more ICs are conspiring against you, they have at least two other modes of communication: whisper over the same wire signals at a lower voltage level that fits in the logic family's tolerances, or with intentional EMI, one chip can radio back and forth with another chip.