3 ms·

It isn't possible to open source the hardware. If the secure enclave is really secure, it has parts that by definition cannot be examined or verified. So hardwa

It isn't possible to open source the hardware. If the secure enclave is really secure, it has parts that by definition cannot be examined or verified. So hardware specs can be open, but you'll never have any guarantee that's what you're getting because hardware is always a compiled blob.

nitrogen 11y ago
Can you list some of these parts that, by your definition, cannot be examined or verified? If you're talking about physical security features to make decapping difficult, surely a high-res xray would be good enough to verify that the hardware is as specified without being able to read the contents of nonvolatile memory, and without compromising physical security.
- vectorjohn 11y ago
  Aren't the contents of NV memory pretty important though? Anyway, it's just different than software. You can't sha sum your hardware to verify its what you expected. I'm not sure, maybe an x-ray could see inside. Not unlike how binary blobs can be examined, but usually that's not considered open.
  - nitrogen 11y ago
    Manufacturers already use x-rays to make sure they're not installing counterfeit chips. Maybe we can look at the verification techniques used for US military procurement or by NASA. I'd wager that we can have open hardware, and that its correct manufacture can be verified to a satisfactory degree by a combination of auditing and testing without running into limits of the laws of physics or inherent design requirements.
- deegles 11y ago
  Question: could an x-ray device be made sensitive/high resolution enough to "read" whether a bit is flipped in silicon? (and extract the private key)
  - tonyarkles 11y ago
    It's a tricky thing, and I fully admit that I have a limited understanding of the specific effects of x-rays on semiconductor devices. My understanding though is that you get higher resolution with higher-energy x-rays, and that as you increase the energy, you're more and more likely to damage the semiconductor (e.g. by inducing bit flips). Here's some material from a flash memory manufacturer with more details: https://www.spansion.com/Support/Application%20Notes/X-ray_inspection_on_flash_AN.pdf https://www.spansion.com/Support/Application%20Notes/X-ray_i...

nitrogen 11y ago

Can you list some of these parts that, by your definition, cannot be examined or verified? If you're talking about physical security features to make decapping difficult, surely a high-res xray would be good enough to verify that the hardware is as specified without being able to read the contents of nonvolatile memory, and without compromising physical security.

vectorjohn 11y ago
Aren't the contents of NV memory pretty important though? Anyway, it's just different than software. You can't sha sum your hardware to verify its what you expected. I'm not sure, maybe an x-ray could see inside. Not unlike how binary blobs can be examined, but usually that's not considered open.
- nitrogen 11y ago
  Manufacturers already use x-rays to make sure they're not installing counterfeit chips. Maybe we can look at the verification techniques used for US military procurement or by NASA. I'd wager that we can have open hardware, and that its correct manufacture can be verified to a satisfactory degree by a combination of auditing and testing without running into limits of the laws of physics or inherent design requirements.
deegles 11y ago
Question: could an x-ray device be made sensitive/high resolution enough to "read" whether a bit is flipped in silicon? (and extract the private key)
- tonyarkles 11y ago
  It's a tricky thing, and I fully admit that I have a limited understanding of the specific effects of x-rays on semiconductor devices. My understanding though is that you get higher resolution with higher-energy x-rays, and that as you increase the energy, you're more and more likely to damage the semiconductor (e.g. by inducing bit flips). Here's some material from a flash memory manufacturer with more details: https://www.spansion.com/Support/Application%20Notes/X-ray_inspection_on_flash_AN.pdf https://www.spansion.com/Support/Application%20Notes/X-ray_i...