3 ms·

The phone in the San Bernardino case is an iPhone 5C which does not have a Secure Enclave. The Secure Enclave (in the iPhone 5S and iPhone 6) has a hardware en

The phone in the San Bernardino case is an iPhone 5C which does not have a Secure Enclave. The Secure Enclave (in the iPhone 5S and iPhone 6) has a hardware enforced rate limiter that cannot be overridden by a firmware update.

comex 11y ago
This is incorrect - the Secure Enclave is a separate CPU, but the rate limiter is still software, and its firmware can (currently) be updated without erasing keys: http://blog.trailofbits.com/2016/02/17/apple-can-comply-with-the-fbi-court-order/ http://blog.trailofbits.com/2016/02/17/apple-can-comply-with...
- threeseed 11y ago
  The rate limiter is in software but that doesn't mean the total number of attempts is in software. Or that there isn't a minimum rate set in hardware. All we know is that Apple at some point increased the delay. Doesn't mean they can decrease it.
- sjwright 11y ago
  This article seems to be largely unsubstantiated speculation. I see no evidence that a locked secure enclave can have its firmware updated.
- mikeash 11y ago
  Where is the evidence that the Secure Enclave's software can be updated without erasing keys? The article states: "Apple can update the SE firmware, it does not require the phone passcode, and it does not wipe user data on update." But it does not support this statement in any way. In my experience, it does either require the phone passcode, or it wipes the data. Of course, I have no idea where that requirement is implemented. It would be easy and sensible to have the secure enclave require the passcode for an update to its own firmware, or erase the keys it holds when applying such an update without the passcode. Apple doesn't say they do it from what I can tell, but it would fit with everything else they do, it's pretty easy to do, and I've seen no indication that it doesn't do this.

3 ms·

The phone in the San Bernardino case is an iPhone 5C which does not have a Secure Enclave. The Secure Enclave (in the iPhone 5S and iPhone 6) has a hardware en

by nemothekid 11y ago

comex 11y ago
This is incorrect - the Secure Enclave is a separate CPU, but the rate limiter is still software, and its firmware can (currently) be updated without erasing keys: http://blog.trailofbits.com/2016/02/17/apple-can-comply-with-the-fbi-court-order/ http://blog.trailofbits.com/2016/02/17/apple-can-comply-with...
- threeseed 11y ago
  The rate limiter is in software but that doesn't mean the total number of attempts is in software. Or that there isn't a minimum rate set in hardware. All we know is that Apple at some point increased the delay. Doesn't mean they can decrease it.
- sjwright 11y ago
  This article seems to be largely unsubstantiated speculation. I see no evidence that a locked secure enclave can have its firmware updated.
- mikeash 11y ago
  Where is the evidence that the Secure Enclave's software can be updated without erasing keys? The article states: "Apple can update the SE firmware, it does not require the phone passcode, and it does not wipe user data on update." But it does not support this statement in any way. In my experience, it does either require the phone passcode, or it wipes the data. Of course, I have no idea where that requirement is implemented. It would be easy and sensible to have the secure enclave require the passcode for an update to its own firmware, or erase the keys it holds when applying such an update without the passcode. Apple doesn't say they do it from what I can tell, but it would fit with everything else they do, it's pretty easy to do, and I've seen no indication that it doesn't do this.