APG

This is a fork of Android Privacy Guard (APG)

I will try to reintegrate the various forks and develope a new user interface and API via AIDL and build a new stable version.

Contribute

Fork APG and do a merge request. I will merge your changes back into the main project.

Build

Build with Ant

1. Add a file called local.properties in org_apg folder with the following lines, altered to your locations of the SDK: sdk.dir=/opt/android-sdk
2. execute "ant release"

Build with Eclipse

1. File -> Import -> Android -> Existing Android Code Into Workspace, choose com_actionbarsherlock
2. File -> Import -> Android -> Existing Android Code Into Workspace, choose org_apg
3. Add com_actionbarsherlock as Android Lib (Properties of org_apg -> Android -> Library -> add)
4. APG can now be build

Libraries

The Libraries are provided in the git repository.

• ActionBarSherlock to provide an ActionBar for Android < 3.0
• Spongy Castle Crypto Lib (Android version of Bouncy Castle)
• android-support-v4.jar: Compatibility Lib
• barcodescanner-android-integration-supportv4.jar: Barcode Scanner Integration

Build Barcode Scanner Integration

1. Checkout their SVN (see http://code.google.com/p/zxing/source/checkout)
2. Change android-home variable in "build.properties" in the main directory to point to your Android SDK
3. Change directory to android-integration
4. Build using "ant build"
5. We use "android-integration-supportv4.jar"

On error see: http://code.google.com/p/zxing/issues/detail?id=1207

Build Spongy Castle

Spongy Castle is the stock Bouncy Castle libraries with a couple of small changes to make it work on Android.

see http://rtyley.github.com/spongycastle/

Notes

Eclipse: "GC overhead limit exceeded"

If you have problems starting APG from Eclipse, consider increasing the memory limits in eclipse.ini. See http://docs.oseems.com/general/application/eclipse/fix-gc-overhead-limit-exceeded for more information.

Generate pressed dashboard icons

1. Open svg file in Inkscape
2. Extensions -> Color -> darker (2 times!)

Security Model

Basic goals

• Never (even with permissions) give out actual PGPSecretKey/PGPSecretKeyRing blobs
• Intents without permissions should only work based on user interaction (e.g. click a button in a dialog)

Android primitives to exchange data: Intent, Intent with return values, Send (also an Intent), Content Provider, AIDL

Intents

Without permission

• android.intent.action.VIEW connected to .gpg and .asc files: Import Key and Decrypt
• android.intent.action.SEND connected to all mime types (text/plain and every binary data like files and images): Encrypt and Decrypt
• IMPORT
• EDIT_KEY
• SELECT_PUBLIC_KEYS
• SELECT_SECRET_KEY
• ENCRYPT
• ENCRYPT_FILE
• DECRYPT
• DECRYPT_FILE

With permission ACCESS_API

• CREATE_KEY
• ENCRYPT_AND_RETURN
• GENERATE_SIGNATURE
• DECRYPT_AND_RETURN

Content Provider

• The whole content provider requires a permission (only read)
• Don't give out blobs
• Make an internal and external content provider (or pathes with )
• Look at android:grantUriPermissions especially for ApgServiceBlobProvider
• Only give out android:readPermission

Remote Service

• The whole service requires the permission ACCESS_API

Resulting permission

• READ_KEY_DATABASE: Read key information (not the actual keys)(content provider)
• ACCESS_API: Encrypt/Sign/Decrypt/Create keys without user interaction (intents, remote service)