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> The second limitation is that it is impractical to audit the hardware to determine whether you have actually received the unmodified open source design. For s

> The second limitation is that it is impractical to audit the hardware to determine whether you have actually received the unmodified open source design. For software this can be achieved using reproducible builds or just by compiling it for yourself. Mostly too expensive AFAIK. I'm fuzzy on the details, but it should be possible to create high-resolution (e.g. X-ray) scans of the chips (as is done by chip design pirates) and compare them to known-good implementations, or images generated based off the chip's open-source design. I'm looking forward to a future where PC auditing shops are a thing. Take in your machine, and let them verify the contents of every chip and storage unit on your device.

jl6 10y ago
Is there really an imaging technology that is high enough resolution to capture the detail of a modern CPU? And if so, would that be sufficient for an audit? Aren't CPUs dependent not just on the layout of circuits but also on the material properties of the components, which might not be apparent just from images?
- asb 10y ago
  This is true, imaging a die can help but it's not enough for full assurance. See e.g. this work on inserting hardware trojans through changing the dopant levels on transistors http://sharps.org/wp-content/uploads/BECKER-CHES.pdf http://sharps.org/wp-content/uploads/BECKER-CHES.pdf
- pjc50 10y ago
  Worse, there isn't currently any nondestructive chip imaging technology!
  - halomru 10y ago
    That just increases the verification costs: order ten chips, verify five randomly chosen ones. If all five are clean, the other five are probably also clean. Modify numbers for the desired cost/risk trade-off.
BuuQu9hu 10y ago
They aren't going to be able to counter analog malicious hardware or dopant level attacks: https://lwn.net/Articles/688751/ https://lwn.net/Articles/688751/
mtgx 10y ago
Perhaps this is a solution? http://engineering.nyu.edu/press-releases/2016/08/23/cybersecurity-researchers-design-chip-checks-sabotage http://engineering.nyu.edu/press-releases/2016/08/23/cyberse...

jl6 10y ago

Is there really an imaging technology that is high enough resolution to capture the detail of a modern CPU? And if so, would that be sufficient for an audit? Aren't CPUs dependent not just on the layout of circuits but also on the material properties of the components, which might not be apparent just from images?

asb 10y ago
This is true, imaging a die can help but it's not enough for full assurance. See e.g. this work on inserting hardware trojans through changing the dopant levels on transistors http://sharps.org/wp-content/uploads/BECKER-CHES.pdf http://sharps.org/wp-content/uploads/BECKER-CHES.pdf
pjc50 10y ago
Worse, there isn't currently any nondestructive chip imaging technology!
- halomru 10y ago
  That just increases the verification costs: order ten chips, verify five randomly chosen ones. If all five are clean, the other five are probably also clean. Modify numbers for the desired cost/risk trade-off.

BuuQu9hu 10y ago

They aren't going to be able to counter analog malicious hardware or dopant level attacks: https://lwn.net/Articles/688751/ https://lwn.net/Articles/688751/

mtgx 10y ago

Perhaps this is a solution? http://engineering.nyu.edu/press-releases/2016/08/23/cybersecurity-researchers-design-chip-checks-sabotage http://engineering.nyu.edu/press-releases/2016/08/23/cyberse...