4 ms·
Actually you don't need to trust the fab: you can get a batch of identical chips, select X% at random (use dice!), grind off the packaging, examine them under a
by a1369209993 13y ago
Actually you don't need to trust the fab: you can get a batch of identical chips, select X% at random (use dice!), grind off the packaging, examine them under a microscope, and compare what you see to the plans you sent to the fab.
Proving that the plans themselves aren't backdoored (your layout software was written by whom exactly?) and aquiring a microscope that can resolve 32nm features without using any integrated circuts (which, by paranoia, we know will identify images of backdoored ICs and replace them with images of non-backdoored ones) is left as a exercise for the reader.
I'm probably forgetting some other attack vectors here, actually.
- kabdib 13y agoCould you extend JTAG to provide verifiable hardware? I'm thinking of something like Vernor Vinge's "trusted computing" stuff in his SF book _Rainbows End_, where a flipflip took 20K gates to implement. You spend a lot of circuitry on attestation. It's probably a circular problem (who will attest to the attestors? etc.), probably devolving into digital signatures of chip layers and stuff, taken before installing CPUs an peripherals... :-/
- anologwintermut 13y agoFPGA's would be a better idea and actually might be viable for a small trusted compute base.
- xradionut 13y agoYou would think that there would be more activity in the OpenCores and other processors on a FPGA systems, but there's not as much I expected when I researched it. Maybe the renewed revelations about the NSA will increase the participation and lower the costs.
- harrytuttle 13y agoYou cant trust the electrical interface to be honest if the hardware isn't honest. If a naughty processor can modify a bunch of instructions, then it can modify its verification results or whatever is provided over the interface.