nsa-away

NSA Away Android application repository for the Hackaday prize

Build

• clone the repo
• from within the Android SDK:
  • File » Import » Existing Projects into Workspace
• Clone and import the one-time-pad-lirbary repo
• Build and import the tess-two Android Tesseract library project (https://github.com/rmtheis/tess-two)
• You may have to update the library project reference in your nsa-away project (in eclipse project, properties, android) depending on the platform you are running
• build and run!

Some design notes:

• This application targets Android 4.x. This keeps prototyping simple, and as Android may not be the ultimate destination platform, investing a lot of effort into compatibility did not make sense

• File access: Our goal is to store keys on external SD cards. Google has greatly complicated secondary storage access with different approaches for the various 4.x versions. Some discussion of that can be found at:

  http://www.androidpolice.com/2014/02/17/external-blues-google-has-brought-big-changes-to-sd-cards-in-kitkat-and-even-samsung-may-be-implementing-them/ http://www.doubleencore.com/2014/03/android-external-storage/

  Since we need to be able to clear used keys, write permission is needed.
  Our initial strategy is for the application to request:

  android.permission.WRITE_EXTERNAL_STORAGE android.permission.READ_EXTERNAL_STORAGE

  and to allow the user to specify a file location for key storage. For KitKat the approach that makes the most sense will likely be to read and write keys in something like:

  /storage/extSdCard/Android/data/org.sector67.nsaaway/files/

  this feels like a hack but should work well enough for the prototype. This will require some coordination with the hardware key generator such that it will generate keys in this location.