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Are there any off-the-shelf options for securing the contents of an SD card so that files written by apps writing to SD are encrypted? If so, what is the best option?

I'm looking for something for all apps. I would strongly prefer to do it without rooting.

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While it's probably possible, I'm not sure if it's feasible, due to the processing costs of encryption. It would drain your battery very quickly. – Arda Xi Oct 5 '10 at 21:13
I've see CPU cost estimate as low as single-digit percentage for file system encryption in other platforms. That would be aceptable... unless processor designs would make it unattainable on this platform. – BrianCooksey Oct 5 '10 at 21:48
Do you want to do this for all apps by modifying the system itself or do you want to implement this in your app? – Felix Oct 5 '10 at 22:32
For all apps. I would prefer to do it without rooting, but I don't expect that to be a realistic restriction for current versions. – BrianCooksey Oct 6 '10 at 0:08
Ice Cream Sandwich has an "Encrypt Phone" option in settings -> Security, but it's not clear if this includes the SD card, or just the internal memory of the phone. – rjmunro Dec 19 '11 at 18:36

The samsung galaxy S has the ability to support a non standard filesystems. Hacking a filesystem together with encryption should be possible but probably takes a lot of time and as far as I know isnt available off the shelf atm.

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For anyone who stumbles upon this topic. Motorola seems to offer a solution for full storage encryption of internal and sd card.


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Sounds like just what the poster's after. It isn't available yet, but should be in early 2011. It will be specific to Motorola Android devices. – GAThrawn Jan 6 '11 at 16:44
Here's what I found on that subject:… – galets Sep 20 '11 at 22:02
The page says it's no longer available. – Dan Dascalescu Jul 6 '14 at 1:02

As of July 2014, I've found the following options for SD card encryption:

  • Boxcryptor - not open source; developed by German company; supports sync with cloud storage; unclear if they've received a backdoor request
  • cryptonite - open source; supports mounting TrueCrypt volumes; no backdoor request yet
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This is the entire purpose of the Guardian Project. Follow their progress - they're working on applications at the moment but they're doing good work and they are attempting to make an android version with transparent encryption.

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Guardian Project hasn't yet released any storage encryption app aimed at the regular user. – Dan Dascalescu Jul 6 '14 at 1:07

Apps typically write to the application storage area which is located in the phone memory, NOT to the SD card. Android 3 and later devices can perform encryption of the complete phone memory. In order to enable this feature, press Settings -> Security and there press Encrypt phone. You must have a lock screen PIN or password set up for this to work.

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"Apps typically write to the application storage area". That depends on whuich apps, adn what data. Photo apps, just as one single example, tipically write to the SD card. This question asks specifically about SD (transparent) encryption. – That Brazilian Guy Oct 29 '13 at 12:43
Virtually any app that writes to the SD card can be forced, one or another way, to use the phone memory instead. The opposite is not true. I believe it is safer to use standard Android features especially when dealing with security. – michael78 Oct 29 '13 at 17:27

"SecureExchange" "" is an application which encrypts/decrypts your private data

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Welcome to Android Enthusiasts. I noticed that your name is the same as the publisher of this app. A rule on this website is that you must disclose any affiliation with a product. – THelper Dec 23 '13 at 8:01

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