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Would encrypting my Android device make my data any safer in case of theft?

It seems to me that since the encryption key necessarily is identical to the PIN code or password used for the key-lock, gaining access to the phone data simply relies on recovering the PIN code or password or somehow bypassing the lock mechanism. And this applies regardless of whether encryption has been applied or not:

  • Without encryption an attacker must unlock the device with the PIN code or password to access any data
  • With encryption an attacker must decrypt the device with the same PIN code or password to access any data

So encrypting the device or not does not seem to actually matter!? In either case the thief must recover the PIN code or password (or bypass the lock mechanism) to access the phone.

Are there any scenarios when encryption actually provides added protection beyond the key-lock, considering the above?

Please consider the case of a factory default Android 4.4 KitKat device, that is not rooted, and that does not have developer options enabled.

Note that I am not aiming to protect my data against people and organizations with extensive capabilities, like forensic and massive code-breaking tools. I'm simply wondering whether enabling encryption actually will really yield any added security against your average hobby hacker with skills in rooting etc.

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Don't ask if you should encrypt your device. That's only asking for opinions and, really, no one can answer for you. Instead, ask about the things you should consider when encrypting (or not). –  Al E. Nov 26 '13 at 18:49
I don't look for general advice about what to consider. I think I already have that covered. I'd like to have it explained to me a plausible scenario for when encryption will actually yield added security considering my risk profile (see updated original question). Thanks. –  Andreas J. Nov 27 '13 at 7:04

7 Answers 7

While it is unfortunate that the PIN for encrypting the device is identical to the unlocking PIN, encryption does still provide much more protection. There are ways to recover unencrypted data without unlocking the device. The main scenario encryption protects against is from an attacker removing the drive from a stolen phone and recovering data with forensic tools.

There are some other scenarios in which encryption will protect your phone. If you have USB debugging enabled on a pre-JB device, an attacker can use ADB to access data. On JB+ the computer accessing the device via ADB must have been already authorized by the phone. Additionally, an attacker could use an exploit to gain access over USB and even get root. Unfortunately crypto will not protect you much in these scenarios because most people keep their devices on with the encryption key in memory at all times, so an attacker could still access the device over USB if debugging is enabled or use an exploit.

So yes, you should encrypt your device with a strong PIN/password if you do not want your data in someone else's hands.

EDIT: grammar/clarity

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I understand that you can never protect your data with a 100% certainty and I don't aim to try and protect my data from people who have access to forensic tools (I'm pretty sure they could gain access to my data if encrypted or not), so your first point is not that relevant to my question. I updated the original post to make this clear. Thanks. –  Andreas J. Nov 27 '13 at 6:45
Furthermore my phone is not rooted, nor does it have developer options enabled, so an attacker should not be able to "use ADB to access data". And since you say, in the case an attacker could gain root access (is this really possible on a screen-locked device?) encryption "will not protect you much", I don't think your answer provides a compelling scenario in which encryption would actually be worthwhile. Would you agree? Thanks. –  Andreas J. Nov 27 '13 at 7:18
  1. Decrypting the device and bypassing the lock mechanism are completely different things. The request for the PIN code/password in the standard lock screen occurs AFTER the device has booted. It is possible bypass it by gaining indirect access to the already available data. And bypassing the lockscreen password is relatively easy. With encryption enabled, it occurs BEFORE the boot and there is NO data that can be obtained without getting the actual key. There is no bypass there, except extracting the key from you by physical force... (An obvious assumption here is that the actual encryption mechanism/software does not have obvious bugs, but this assumtion undermines ANY discussion on security whatsoever, so I'm not taking it into account).

  2. Your phone may have an external SD Card with lots of data on it (like mine). Encryption will protect it if the phone is lost, since ejecting it and trying to mount it elsewhere will fail. That's not a "forensic-level" attack.

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Encryption only becomes valuable if there is a risk that an attacker could use a software vulnerability to bypass the login screen.

There have been some examples of this due to vulnerabilities in various apps (e.g. Viber and Skype) and devices (Samsung) but presumably those flaws have been fixed by now. New vulnerabilities could however appear.

If you have developer option USB debugging turned on, or if the device is rooted, there are many hacks that will bypass the screen lock (here is one example; there are many more discussed at xda-developers forum).

However, on a factory default device (no root, no developer settings) of recent manufacturing and Android version there are no known hacks that I'm aware of that will bypass the lock-screen, except for occasional software vulnerabilities such as those mentioned above.

On the other hand, if let's say for example instead the encryption key was different from the PIN code or password then encryption would definitely be worthwhile, because a possible scenario could then be that an attacker could obtain the PIN code or password (e.g. by reading the unlock pattern on the screen or brute force cracking the PIN), but still wouldn't be able to access the data on the phone since it would be encrypted with a very strong (and different) encryption key.

Note that if you have a rooted device there is a way to apply an encryption key that is different from the PIN code or password. Please see neopran's answer.

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The main difference between an encrypted device and an un-encrypted device is that a code must be entered every time the device is booted on. Does that simple layer of security add any benefits to your everyday life? That's a question only you can answer. Otherwise there isn't much of a digital security benefit. The encryption security feature seems more practical in a theft situation. It would make it almost impossible for the everyday thief to use your private information against you. Hope I helped in anyway. (:

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How is encryption more secure than using just the key-lock? In either case it is the same pin code or password that protects your data. Please read my question again. –  Andreas J. Dec 8 '13 at 18:56

Actually your missing the main point of encryption.

Lets say all you have is a PIN on your phone. If I get a hold of your phone I can simply hook it up to my linux machine, or even pc, and get documents, pictures, see your logs from internet see what apps you have installed get your data from those apps and import them into a different phone install that app place your data in the right folder and volia.

Then text messages, call logs and everything else is kept on device. Doesnt take long at all even with say "Notepad" to read parts of text messages. Now there will be a bunch of random characters and i mean pages upon pages of nonsense that makes no sense but there will be readable text in there, and thats all without using third party apps.

This all can happen regardless if you have your phone locked or not locked when hooked into a different machine.

NOW AN ENCRYPTED PHONE lets say I get your phone but don't have your code. YOUR INFO EVERYTHING ABOVE although still accessible its garbled makes no sense even the pictures everything is encrypted.

Obviously this is assuming your talking about Whole Phone Encryption and not just a boot up password which IS NOT ENCRYPTION.

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Good point, however, as far as I know unless one unlocks the screen lock on the phone it will not mount when connected to a PC (Windows or Linux) so you wouldn't be able to read my documents without breaking the screen lock, which brings us back to my original question. Am I wrong? –  Andreas J. Sep 22 '14 at 18:34
thats false i can mount with or without a lock on android. Im doing it now. In windows you just have to change the permissions over from an administrator account. On linux based systems its even easier. Not sure on windows phones though. Im running KitKat 4.4.2 on a Note 3. –  Neog2 Sep 29 '14 at 5:04
If that's true, I think your answer qualifies as a solution to my question, however, I cannot find support for your statement online. Could you please provide links that describe how to mount locked phones. Thanks. –  Andreas J. Oct 1 '14 at 23:53

Key lock, PIN or password do not offer any protection if the phone's bootloader isn't locked. For example, most of Samsung devices (except ones from Verizon or AT&T and some other providers I never heard) have unlocked bootloaders, at least in Europe.

If you don't have your data encrypted, one only has to flash a custom recovery, which is very easy, and the job is finished. Such recoveries can mount partitions, and mount USB stick by using OTG cable.

So, encryption is "added security against your average hobby hacker with skills in rooting etc." because that, or even less than that, are all required skills one needs to get data from a device with strong password, but unlocked bootloader.

The issue with locked bootloader is that unlocking it would usually wipe all data from the device.

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You could always use an app like this: https://play.google.com/store/apps/details?id=org.nick.cryptfs.passwdmanager

I use it on my phone and it works very well, just make sure you read the instructions and keep them in mind.

Your phone also has to be rooted for this app to work though.

I'd say it definitely makes your data safer if your phone ever does get stolen!

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Thank, my phone is not rooted. –  Andreas J. Nov 27 '13 at 6:31
Can you please motivate why encryption "definitely makes your data safer" considering my original question and the fact that my phone is not rooted? –  Andreas J. Nov 27 '13 at 6:33

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