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A port of gnupg to Android

branch: master
Octocat-spinner-32 .externalToolBuilders Disable auto builder in eclipse January 29, 2013
Octocat-spinner-32 .tx update transifex config to point to new name: "gpg" rather than "gpgcli" September 11, 2013
Octocat-spinner-32 assets adb is now in $ANDROID_HOME/platform-tools April 04, 2014
Octocat-spinner-32 docs add pinentry implementation diagram June 09, 2013
Octocat-spinner-32 external purge references to iconv, its not needed, Android is UTF-8 April 04, 2014
Octocat-spinner-32 jni replace hack using private header with public gpgme_signers_count() March 17, 2014
Octocat-spinner-32 libs Eclipse ADT insists on exporting appcompat's LIBRARIES and DEPENDENCIES January 30, 2014
Octocat-spinner-32 res "Delete Keys" from the Public Keys tab's ActionBar March 13, 2014
Octocat-spinner-32 src fix crash when encrypting a file with no keys in keyring March 17, 2014
Octocat-spinner-32 tests added Android Test Project embedded into this app, as recommended January 15, 2014
Octocat-spinner-32 .classpath replace ActionBarSherlock with android-support-v7-appcompat January 15, 2014
Octocat-spinner-32 .gitignore include all GnuPG test suites that will run in Android January 30, 2014
Octocat-spinner-32 .gitmodules replace ActionBarSherlock with android-support-v7-appcompat January 15, 2014
Octocat-spinner-32 .project include the external build NDKBuilder since Eclipse will freak out wi… August 09, 2012
Octocat-spinner-32 AndroidManifest.xml bump to version code 6 name 0.3.2 April 04, 2014
Octocat-spinner-32 ChangeLog.txt update ChangeLog for new release April 04, 2014
Octocat-spinner-32 Description.txt updated Google Play description (4000 char limit) March 13, 2014
Octocat-spinner-32 LICENSE.txt add LICENSE.txt with GPLv3+ May 08, 2013
Octocat-spinner-32 update build setup info in README March 18, 2014
Octocat-spinner-32 format JNI C code with astyle. styled included in documentation December 03, 2013
Octocat-spinner-32 icon.png new icon made by taking GPGMail icon and converting to Guardian Green May 08, 2013
Octocat-spinner-32 set the version code and name based on current date March 13, 2014
Octocat-spinner-32 fix final signing step in release build script July 26, 2013
Octocat-spinner-32 replace ActionBarSherlock with android-support-v7-appcompat January 15, 2014
Octocat-spinner-32 replace ActionBarSherlock with android-support-v7-appcompat January 15, 2014

Gnu Privacy Guard for Android

A port of the whole GnuPG 2.1 suite to Android.

If you are using these tools in your own apps, we'd love to hear about it. Email us at

Gnu Privacy Guard (GPG) gives you access to the entire GnuPG suite of encryption software. GnuPG is GNU’s tool for end-to-end secure communication and encrypted data storage. This trusted protocol is the free software alternative to PGP. GnuPG 2.1 is the new modularized version of GnuPG that now supports OpenPGP and S/MIME.

Using Gnu Privacy Guard's Android Integration

One of the core goals of Gnu Privacy Guard is to provide integrated encryption support in a way that feels natural on Android. That means it tries to be as transparent as possible, and only pop up with there is no other way:

  • if you want to send someone an encrypted file, find them in your Contacts/People app, and click on "Encrypt File To"
  • if you want encrypt something, then share it to Gnu Privacy Guard
  • if you want to view an encrypted file, share it with Gnu Privacy Guard and it'll prompt you for your password and the app to view it with
  • if you want to import keys into your keyring, there are a few ways to do it:
    • click on a .pkr, .skr, .key, or pubring.gpg file in your email, dropbox, SD card, etc.
    • click on a fingerprint URL, for example: openpgp4fpr:9F0FE587374BBE81
    • scan a fingerprint QRCode

Look for more features in the Android integration, and please post your ideas in our issues tracker:

Using Gnu Privacy Guard from the Terminal

Before using Gnu Privacy Guard, be sure to launch the app and let it finish its installation process. Once it has completed, then you're ready to use it. The easiest way to get started with Gnu Privacy Guard is to install Android Terminal Emulator. gpgcli will automatically configure Android Terminal Emulator as long as you have the "Allow PATH extensions" settings enabled. Get the Android Terminal Emulator at

Currently, this app offers the full gnupg suite of commands in the terminal. When you run the GnuPG tools in an app, a GNUPGHOME folder will be created for that specific app. Because of the Android permissions model, its not possible to create a shared GNUPGHOME without having it world-writable.

Use in Android Terminal Emulator

The app automatically configures Android Terminal Emulator to use the GnuPG tools, as long as you have the Allow PATH extensions preference set.

Manual configuration and using it with other apps

In order to use the GnuPG tools in your app, preferred terminal emulator, or adb shell, you need to set the PATH to include the full path to the GnuPG aliases, for example:

export PATH=$PATH:/data/data/info.guardianproject.gpg/app_opt/aliases

Or you can call the aliases using the full path:

/data/data/info.guardianproject.gpg/app_opt/aliases/gpg --encrypt secretfile.txt

WARNING: The above method stores key material inside the data dir of Gnu Privacy Guard

Gnu Privacy Guard is not able to read your key material, only root or your app can, but the material will remain after the app is uninstalled. If this is not desirable for you then you should set the environment variables managed in


and set the PATH to /data/data/info.guardianproject.gpg/app_opt/bin:$PATH instead of using the aliases method described above.

At a minimum you should set the environment variables LD_LIBRARY_PATH, HOME, GNUPGHOME, and PATH.

GNUPGHOME should be set to a secure path inside your app's data directory, for example you could call getDir("gnupghome") from your Activity.

Setting up all of the tools

To enable the whole suite of tools, including dirmngr to work with keyservers, you need to set another environment variable:

export LD_LIBRARY_PATH=$LD_LIBRARY_PATH:/data/data/info.guardianproject.gpg/app_opt/lib:/data/data/info.guardianproject.gpg/lib

The technical reason why is that GnuPG uses a lot of shared libraries, and the only way Android has for finding shared libraries is the LD_LIBRARY_PATH environment variable. GNU/Linux has rpath, Mac OS X has install names, but Android has none of this stuff.

Please Report Bugs

This is an early release of a big project, so there will inevitable be bugs. Help us improve this software by filing bug reports about any problem that you encounter. Feature requests are also welcome!

Target Platform

We would like to target as many Android platforms as possible. Currently there are two limiting APIs:

  • regex - provided in Android 2.2, SDK android-8 and above
  • pthread_rwlock* - provided in Android 2.3, SDK android-9 and above
  • pthread_atfork - provided in Android 4.0, SDK android-14 and above

regex could easily be included in the build, pthread_rwlock\* would be more difficult. pthread_atfork is not really fully required, but might be in the future.

Build Setup


sudo apt-get install build-essential autoconf automake-1.11 libtool \
    transfig wget patch texinfo ant gettext bison

Fedora 17 x64

sudo yum install autoconf automake libtool transfig wget patch texinfo \
    ant gettext bison \
    ncurses-libs.i686 libstdc++.i686 libgcc.i686 zlib.i686 gcc.i686

You might need to apply some patches to get GnuPG subprojects building with newer versions of automake:

Android SDK, NDK, appcompat

Install the Android NDK v9b or newer for the command line version, and the Android SDK for the Android app version:

If you are building in Eclipse or IntelliJ, you need to also set up the android-support-v7-appcompat library project:


First the get all of the source code from git:

git clone
git submodule update --init --recursive

How to build the whole app

make -C external/ distclean clean-assets
make -C external/
ndk-build clean
ant clean debug

Running the GnuPG tests

The GnuPG subprojects all include their own test suites. They end up being quite large, so they are not included in the APK by default. If you want to include all of the tests, then run make -C external/ assets-tests before ndk-build. That gives you the same sequence as used in, which is how we run our tests:

make -C external/ distclean clean-assets
make -C external/
make -C external/ assets-tests
ndk-build clean
ant clean debug

Then to run the tests, first install the APK and run it so that it sets up all of its included assets. Once the Android app has completed its initial setup, run:


How to Build Individual Components

To compile the components individually you can use commands like (the order that you run them is important):

make -C external/ gnupg-install
make -C external/ gnupg-static
make -C external/ gpgme-install

The results will be in external/data/data/info.guardianproject.gpg

How to Build the Android Test App

make -C external/ clean-assets
make -C external/ android-assets
android update project --path . --name GnuPrivacyGuard
ant clean debug

Hacking Notes

Please conform to our code format standard.

For C files use

For Java, please apply the official Android formatter profile

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