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Why the worry about auto-wiping? Is it not possible to make a copy of the encrypted data and then play around with it as much as you want?
by Myrmornis 11y ago
Why the worry about auto-wiping? Is it not possible to make a copy of the encrypted data and then play around with it as much as you want?
- peeters 11y agoYeah I've got the same question. Is there some hardware safeguard that prevents copying the memory itself? You'd think the first rule of crypto forensics is to work on a copy.
- X-Istence 11y agoEven if there were no such safeguard, you'd still have to break AES encryption...
- greiskul 11y agoThey "just" need to break the users password. If it's a weak one, which is likely for most users, a simple dictionary attack would work.
- deleted 11y ago[deleted]
- X-Istence 11y agoThe users password goes through a password based key derivation function, that function spits out an key that is use for the AES crypto used for the file system. Now, the PBKDF requires a secret that is only stored within the iPhone itself (within the CPU even, where it can't be read out directly). So if we instead grab a copy of the data, all we get is an AES encrypted file system. We have 2 choices. 1. We can attack AES directly, and attempt to brute force the AES key, or 2. We can attempt to get the AES key somehow by bruteforcing the users password. 2 is infinitely simpler compared to 1. However, 2 becomes more difficult (but still less so than just cracking AES itself) when you need to run your brute force guesses through the CPU within the iPhone.
- peeters 11y agoI guess that's my question...is there really no way to get the secret off of the hardware so that the function can be reproduced "offline".
- X-Istence 11y agorestating your question: Has Apple been lying to its customers for years?
- ascorbic 11y agoThis is exactly the threat model this was designed to defeat, so I would imagine not. At the very least, if there is a way to do it Apple is probably unaware. If they are aware, they'll probably open themselves to a class action suit, as its one of the core features that they advertised.
- deleted 11y ago[deleted]
- scottcanoni 11y agoCan someone answer this? Raw read the memory to an external device and then brute force that shit using super computers until it cries.
- X-Istence 11y agoIf you can break AES... then the NSA would love to have a word with you :P The FBI is going after the lowest hanging fruit, the users password that was used to create the crypto key.
- superuser2 11y agoThe user's password is not used to create the crypto key; it is randomly generated and burned in at the factory.
- X-Istence 11y agoIt is used to create the crypto key, using a password based key derivation function, using the user's password fed into the PBKDF the output is the key used for encryption/decryption. The users device key is mixed into that PBKDF. Without both parts of the equation, you have nothing. For your reading enjoyment: https://www.apple.com/business/docs/iOS_Security_Guide.pdf https://www.apple.com/business/docs/iOS_Security_Guide.pdf Specifically page 11 the diagram at the bottom.
- stepanhruda 11y agoDamn, that's a great idea. Talk to you in a billion billion years. http://www.eetimes.com/document.asp?doc_id=1279619 http://www.eetimes.com/document.asp?doc_id=1279619
- tptacek 11y agoThe data the DOJ wants is encrypted with AES, so all the phone has to wipe is the key; a copy of the encrypted data is useless.
- philip1209 11y agoThis seems like a key thing to convey to the courts. One piece of encrypted data is supplied, rather than another. Who has to explain to the courts the complexity of breaking one versus the other?