4 ms·

Unless there is a bug in their hardware implementation of AES-CCM or (shudder) some sort of crazy disclosure vulnerability in the APIs they provide, there is (p

Unless there is a bug in their hardware implementation of AES-CCM or (shudder) some sort of crazy disclosure vulnerability in the APIs they provide, there is (presumably) no way to get at the UID. Even if you were to decap the chip and get at the UID physically, you still aren't any better off as it derives the actual encryption key on boot from the UID. The Secure Enclave is essentially a hardware security module, in more general terms. The only thing that leaves its boundaries are the results of crypto operations, not the parameters that went into calculating them.

teekert 11y ago
Thank you. So you mean to say that making an electron micrograph of this chip will not even reveal it's secrets? If the data persists after removal of power, some physical structure contains the data. Somewhere a hash of the fingerprint/password needs to be stored, then somewhere the function to compute that into an AES cipher needs to be stored. I'm going on and on about this because I see no way in which this problem is not down-boil-able to brute-forcing the password the user puts in. Actually Apple admits this much! They can build a work around! What stops the three-letter-agency from building it? There must at some point be a complex user entered passphrase if you want to be safe. This can be a fingerprint of course but there is always the 4 letter password/passphrase that is the weak point. I could be completely wrong, so far I'm not convinced I am.
chillaxtian 11y ago
on page 11 of the security white paper, there is a diagram illustrating the key hierarchy. i believe that 'Hardware Key' refers to the UID. if this is the case, then learning the UID + user passcode gives you the root keys, from which you can decrypt the remaining key hierarchy until you reach the decrypted files.

4 ms·

Unless there is a bug in their hardware implementation of AES-CCM or (shudder) some sort of crazy disclosure vulnerability in the APIs they provide, there is (p

by evanosaurus 11y ago

teekert 11y ago
Thank you. So you mean to say that making an electron micrograph of this chip will not even reveal it's secrets? If the data persists after removal of power, some physical structure contains the data. Somewhere a hash of the fingerprint/password needs to be stored, then somewhere the function to compute that into an AES cipher needs to be stored. I'm going on and on about this because I see no way in which this problem is not down-boil-able to brute-forcing the password the user puts in. Actually Apple admits this much! They can build a work around! What stops the three-letter-agency from building it? There must at some point be a complex user entered passphrase if you want to be safe. This can be a fingerprint of course but there is always the 4 letter password/passphrase that is the weak point. I could be completely wrong, so far I'm not convinced I am.
chillaxtian 11y ago
on page 11 of the security white paper, there is a diagram illustrating the key hierarchy. i believe that 'Hardware Key' refers to the UID. if this is the case, then learning the UID + user passcode gives you the root keys, from which you can decrypt the remaining key hierarchy until you reach the decrypted files.