Post Syndicated from corbet original https://lwn.net/Articles/964956/

Andrew ‘bunnie’ Huang provides an update on
his IRIS infrared chip-scanning project as the starting point for a
detailed summary on how chip customers can detect forgeries and
modifications in general.

The technique works because although silicon looks opaque at
visible light, it is transparent starting at near-infrared
wavelengths (roughly 1000 nm and longer). Today’s commodity optics
and CMOS cameras are actually capable of working with lights at
this wavelength; thus, IRIS is a low-cost and effective technique
for confirming the construction of chips down to block level. For
example, IRIS can readily help determine if a chip has the correct
amount of RAM, number of CPU cores, peripherals, bond pads,
etc. This level of verification would be sufficient to deter most
counterfeits or substitutions.