DRM for Apps downloaded via Google Play [LWN.net]

DRM for Apps downloaded via Google Play

Posted Jun 28, 2012 11:57 UTC (Thu) by csamuel (✭ supporter ✭, #2624)
Parent article: Android 4.1 Jelly Bean: faster, smoother, more delightful (ars technica)

Android 4.1 includes a form of DRM for applications downloaded from Google Play, as the developers document says:

Starting with Android 4.1, Google Play will help protect application assets by encrypting all paid apps with a device-specific key before they are delivered and stored on a device.

This will presumably make it a lot harder to identify if someone has copied your code into their application.

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DRM for Apps downloaded via Google Play

Posted Jun 29, 2012 23:56 UTC (Fri) by zlynx (subscriber, #2285) [Link]

But not impossible.

Here's one method to get at the code: load a modified ROM with a customized Dalvik which copies the decrypted bytecode somewhere.

Assuming that the hardware allows loading modified ROMs of course.

If it doesn't, then you're into mod-chip territory and you'd need something to perhaps freeze the CPU clock and dump the RAM.

Which yes, would qualify as "a lot harder."

DRM for Apps downloaded via Google Play

Posted Jul 3, 2012 8:34 UTC (Tue) by rich0 (guest, #55509) [Link]

Doubt you'd even have to do that much, unless they build the decryption into the CPUs or something.

DRM of any kind suffers from the Bob = Eve problem - it is cryptographically unsound. I'm sure once the source is available there will be software readily available to extract the device key and then you can just decrypt the apks either on the device or elsewhere.

To really get DRM to work on Android would require locking it WAY down - so much that I doubt that many LWN readers would be interested in it any longer. This seems to be more of a token gesture. I'm sure it will be unbreakable for a week or two...