open-keychain/README.md

# OpenPGP Keychain (for Android)

OpenPGP Keychain is an OpenPGP implementation for Android.
The development began as a fork of Android Privacy Guard (APG).

see http://sufficientlysecure.org/keychain

# Build

## Build with Gradle

1. Have Android SDK "tools", "platform-tools", and "build-tools" directories in your PATH (http://developer.android.com/sdk/index.html)
2. Export ANDROID_HOME pointing to your Android SDK
3. Install gradle
4. Execute ``gradle wrapper`` (http://www.gradle.org/docs/current/userguide/gradle_wrapper.html)
5. Execute ``./gradlew build``

## Build with Ant

1. Have Android SDK "tools" directory in your PATH (http://developer.android.com/sdk/index.html)
2. Execute ``android update project -p OpenPGP-Keychain``
3. Execute ``android update project -p libraries/ActionBarSherlock``
3. Execute ``android update project -p libraries/HtmlTextView``
3. Execute ``cd OpenPGP-Kechain``, ``ant debug``

# Contribute

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

## Development with Eclipse

Android Studio is currently not supported or recommended!

1. File -> Import -> Android -> Existing Android Code Into Workspace, choose "libraries/ActionBarSherlock"
1. File -> Import -> Android -> Existing Android Code Into Workspace, choose "libraries/HtmlTextView"
2. File -> Import -> Android -> Existing Android Code Into Workspace, choose "OpenPGP-Keychain"
3. OpenPGP-Kechain can now be build

# Keychain API

## Intent API
All Intents require user interaction, e.g. to finally encrypt the user needs to press the "Encrypt" button.
To do automatic encryption/decryption/sign/verify use the OpenPGP Remote API.

#### Android Intent actions provided by OpenPGP Keychain:

* ``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

#### OpenPGP Keychain specific Intent actions:

* ``org.sufficientlysecure.keychain.action.ENCRYPT``
  * To encrypt or sign text, use extra ``text`` (type: ``String``)
  * or set data ``Uri`` (``intent.setData()``) pointing to a file
  * Enable ASCII Armor for file encryption (encoding to Radix-64, 33% overhead) by adding the extra ``ascii_armor`` with value ``true``
* ``org.sufficientlysecure.keychain.action.DECRYPT``
  * To decrypt or verify text, use extra ``text`` (type: ``String``)
  * or set data ``Uri`` (``intent.setData()``) pointing to a file
* ``org.sufficientlysecure.keychain.action.IMPORT_KEY``
  * Extras: ``key_bytes`` (type: ``byte[]``)
  * or set data ``Uri`` (``intent.setData()``) pointing to a file
* ``org.sufficientlysecure.keychain.action.IMPORT_KEY_FROM_QR_CODE``
  * without extras, starts Barcode Scanner to get QR Code

## OpenPGP Remote API
To do asyncronous fast encryption/decryption/sign/verify operations bind to the OpenPGP remote service.
The API Demo contains all required AIDL files and a demo activity.

#### Try out the API
Keychain: https://play.google.com/store/apps/details?id=org.sufficientlysecure.keychain  
API Demo: https://play.google.com/store/apps/details?id=org.sufficientlysecure.keychain.demo

#### Design
All apps wanting to use this generic API
just need to include the AIDL files and connect to the service. Other
OpenPGP apps can implement a service based on this AIDL definition.

The API is designed to be as easy as possible to use by apps like
K-9 Mail. The service definition defines
sign/encrypt/signAndEncrypt/decryptAndVerify [1].

As can be seen the apps themselves never need handle key ids directly.
Only user ids (emails) are used to define recipients. If more than one
pub key exists for an email, OpenPGP Keychain will handle the problem by
showing a selection screen.

Also app devs never need to fiddle with private keys. On first
operation, OpenPGP Keychain shows an activity to allow or disallow
access, while also allowing to choose the private key used for this app.
Please try the Demo app out to see how it works [4].

#### Integration
The API is defined as AIDL interfaces in org.openintents.openpgp packge
[2]. All files from [2] needs to be included in the project.

Using the OpenPgpServiceConnection.java [3] you can choose to which
OpenPGP provider you want to connect (other pgp apps can implement the
interfaces). They can be queried as shown in the demo app (see [3] how
to query). If other OpenPGP apps implement the service, no additional
code is required in k9mail per provider. See [3] for a complete example
for integration.

[1] https://github.com/dschuermann/openpgp-keychain/blob/master/OpenPGP-Keychain-API-Demo/src/org/openintents/openpgp/IOpenPgpService.aidl  
[2] https://github.com/dschuermann/openpgp-keychain/tree/master/OpenPGP-Keychain-API-Demo/src/org/openintents/openpgp  
[3] https://github.com/dschuermann/openpgp-keychain/blob/master/OpenPGP-Keychain-API-Demo/src/org/openintents/openpgp/OpenPgpServiceConnection.java  
[3] https://github.com/dschuermann/openpgp-keychain/blob/master/OpenPGP-Keychain-API-Demo/src/org/sufficientlysecure/keychain/demo/OpenPgpProviderActivity.java  
[4] https://play.google.com/store/apps/details?id=org.sufficientlysecure.keychain.demo

## Extended Remote API

TODO

# Libraries

All JAR-Libraries are provided in this repository under "libs", all Android Library projects are under "libraries".

* ActionBarSherlock to provide an ActionBar for Android < 3.0
* HtmlTextView for non-crashing TextViews with HTML content
* forked Spongy Castle Crypto Lib (Android version of Bouncy Castle)
* 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


## Bouncy Castle

#### Spongy Castle

Spongy Castle is the stock Bouncy Castle libraries with a couple of small changes to make it work on Android. OpenPGP Keychain uses a forked version with some small changes to improve key import speed. These changes have been sent to Bouncy Castle, and Spongy Castle will be used again when they have filtered down.

see
* Spongy Castle: http://rtyley.github.com/spongycastle/
* Fork: https://github.com/ashh87/spongycastle

#### Bouncy Castle resources

* Repository: https://github.com/bcgit/bc-java
* Issue tracker: http://www.bouncycastle.org/jira/browse/BJA

#### Documentation
* Documentation project at http://www.cryptoworkshop.com/guide/
* Tests in https://github.com/bcgit/bc-java/tree/master/pg/src/test/java/org/bouncycastle/openpgp/test
* Mailinglist Archive at http://bouncy-castle.1462172.n4.nabble.com/Bouncy-Castle-Dev-f1462173.html


# Notes

## Eclipse: "GC overhead limit exceeded"

If you have problems starting OpenPGP Kechain 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!)

# Coding Style

## Code
* Indentation: 4 spaces, no tabs
* Maximum line width for code and comments: 100
* Opening braces don't go on their own line
* Field names: Non-public, non-static fields start with m.
* Acronyms are words: Treat acronyms as words in names, yielding !XmlHttpRequest, getUrl(), etc.

See http://source.android.com/source/code-style.html

## XML Eclipse Settings
* XML Maximum line width 999
* XML: Split multiple attributes each on a new line (Eclipse: Properties -> XML -> XML Files -> Editor)
* XML: Indent using spaces with Indention size 4 (Eclipse: Properties -> XML -> XML Files -> Editor)

See http://www.androidpolice.com/2009/11/04/auto-formatting-android-xml-files-with-eclipse/

# Licenses
OpenPGP Kechain is licensed under GPLv3+.
Some parts (older parts and some libraries are Apache License v2, MIT X11 License)

> This program is free software: you can redistribute it and/or modify
> it under the terms of the GNU General Public License as published by
> the Free Software Foundation, either version 3 of the License, or
> (at your option) any later version.
> 
> This program is distributed in the hope that it will be useful,
> but WITHOUT ANY WARRANTY; without even the implied warranty of
> MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> GNU General Public License for more details.
> 
> You should have received a copy of the GNU General Public License
> along with this program.  If not, see <http://www.gnu.org/licenses/>.


## Libraries

* SpongyCastle  
  https://github.com/rtyley/spongycastle  
  MIT X11 License

* ActionBarSherlock  
  http://actionbarsherlock.com/  
  Apache License v2

* HtmlTextView  
  https://github.com/dschuermann/html-textview  
  Apache License v2

* ZXing QRCode Integration  
  http://code.google.com/p/zxing/  
  Apache License v2


## Images
* icon.svg  
  modified version of kgpg_key2_kopete.svgz

* dashboard_manage_keys.svg, dashboard_my_keys.svg, key.svg  
  http://rrze-icon-set.berlios.de/  
  Creative Commons Attribution Share-Alike licence 3.0

* dashboard_decrypt.svg, dashboard_encrypt.svg, dashboard_help.svg  
  http://tango.freedesktop.org/  
  Public Domain

* dashboard_scan_qrcode.svg  
  New creation for OpenPGP Kechain  
  Apache License v2