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Excuse my stupidity, I know less than nothing about mobile phones OSes but I have been told that iOS encrypts your data when you set a passcode to your phone. This means even if someone stole your phone, took the storage unit out of the phone and mount it he will NOT be able to to examine your data as it encrypted. Something similar to what *nix OSes do when you choose to encrypt your home folder during the installation process.

My concerns are:

  • What type of data does it encrypt? it's hard to believe that my iPhone decrypts all my photos once I enter my passcode (assuming that iOS encrypted them)
  • How difficult is it to crack an encryption that is based on simple four digits?!
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Yes, your iOS passcode will encrypt your phone's data.

Data protection enhances the built-in hardware encryption by protecting the hardware encryption keys with your passcode.

Source: iOS: Understanding data protection

Whilst it was generally unclear exactly what was encrypted in older versions of iOS, Apple have made it clear in their new privacy policy with regard to iOS 8:

On devices running iOS 8, your personal data such as photos, messages (including attachments), email, contacts, call history, iTunes content, notes, and reminders is placed under the protection of your passcode.

Source: https://www.apple.com/uk/privacy/government-information-requests/

  • Here's another document with lots of detail about security in iOS, including exactly how data protection works: s3.amazonaws.com/s3.documentcloud.org/documents/1302613/… – Jay Thompson Nov 25 '14 at 15:09
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    no , wrong , i got iphon 4S (NOT JAILBROOKEN) strong pass inside , all the roll camera data can be accessed with itools aswell , so i dont see where is the purpose of that code ! – K3rnel31 Sep 3 '15 at 12:04
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    I agree with @K3rnel31. I have a jailed iOS 9 iPhone 6. Hook up iExplorer without unlocking the phone, and I can browse the photos no problem. Something's not kosher here. :( – Nate Mar 28 '16 at 4:33
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In regard to your question about how hard it would be to crack, it would need to try a maximum of 10,000 passcodes to get it right, so (I think) it isn't that secure if the hard drive is removed and could be decrypted. If you are worried about security, you can set a passcode with letters - you need to turn off Simple Passcode.

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Addressing: "How difficult is it to crack an encryption that is based on simple four digits?!"

This is a deeper question than you might expect. And much of the following is over-simplified to save time and explaining background concepts. If you are talking about ios8 the answer is different than if you were talking about ios7 or earlier.

In iOS7 and earlier the phone could be imaged, and decryption of the image could be attempted on a desktop system with all 10,000 possible 4 digit pins more or less instantaneously. Also Apple maintained a separate key they could use to decrypt the device if served a warrant.

In iOS8 decryption must be performed on device as it uses a devise specific number (that cannot be extracted from the device) in addition to your pin for encryption; this also prevents Apple from decrypting the device under warrant so you are protected from various three letter organizations serving baseless warrants as Apple has no more advantage in decrypting your device over anyone else. This requirement to perform decryption on-device significantly slows the rate of attempts. If you have "erase data after 10 failed attempts" enabled, then this further slows the process as an attacker would have to image the phone, attempt 10 pins on device (with exponential backoff) and after that run of 10, restore the device with your image.

I'm not familiar with the software that exists to perform these tasks, so I can't estimate how long it would take to try all 10,000 pins under these circumstances; however it is worthwhile to note that the director of the FBI and the US attorney general are throwing tantrums because of it, so presumably it is enough to make their lives more difficult.

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It all depends on the algorithms being used. AES is a very fast algorithm, but it also depends on the mode of operation. Assume that Apple used AES or 3DES because they are standardized. Now, computation of the plaintext is only possible (at the moment) with an exhaustive search attack. But the attacker can manipulate the plaintext. But that would not do much good in a counter-terrorism operation. Never corrupt the data if it is important. If the attacker was spying using software such as VNC, (if such software exists for iOS), or an advanced touch Keylogger, unless he had access by ssh, he would probably not have been able to install the Keylogger, unless he had previous info on the UI decryption key (not for hardware decryption). If he gets an image of the device, he can perform an online attack on the UI encryption, but he can't change the code, without data corruption. This means he will be locked out after several failed attempts. If the attacker manages to get a hold of the disk, he can perform an offline attack. But this is much harder, as hardware encryption is on. The attacker will eventually win, but will it do any good?

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