3 ms·
> if the slow authentication is inherent from running the algorithm on the chip, rather than a having been slowed down artificially There is no known cryptogra
by 542458 11y ago
> if the slow authentication is inherent from running the algorithm on the chip, rather than a having been slowed down artificially
There is no known cryptographic algorithm that provides inherently increasing times. The slowdown is entirely artificial, and it is believed that an update could remove it.
- 4ad 11y agoI was under the impression that the algorithm (running on the secure enclave?) takes at least 200ms. Yes, obviously longer times are artificial, but my question is whether the 200ms baseline is artificial or not. Of course this doesn't really matter at all if modified software could just read the key from the chip. That is the most interesting question. So, can it? Or can the software only provide data to the chip, to do the algorithm in hardware, but the software can't read the key burned (?) into the chip.
- 542458 11y agoThe 200ms hash baseline (on all up-to-date iPhones) is not artificial, but the increasing time is. Unfortunately, I don't believe the answers to your other questions are known to anybody other than Apple right now.
- pfg 11y agoTheir hash algorithm takes ~80ms per attempt. All crypto happens on a dedicated AES engine. Files are encrypted with a key derived from UID (device key which cannot be extracted via firmware) and passphrase.
- 4ad 11y agoSo if the key can't be extracted via the firmware, someone updating the firmware, even with malicious intent, should not be a problem, am I correct?