Add first basic implementation of Apgservice

Provides an AIDL-API for other apps to encrypt and decrypt a string
symmetrically with a passphrase. Function names and API is by no way
finalized and will change!

Support for asymetric encription will follow.

For reference and discussion see issue #71,
https://code.google.com/p/android-privacy-guard/issues/detail?id=71

AndroidManifest.xml

@@ -195,7 +195,11 @@
             android:configChanges="keyboardHidden|orientation|keyboard"/>
 
         <service android:name=".Service" />
-
+        <service android:name=".ApgService" android:enabled="true" android:exported="true" android:process=":remote" >
+            <intent-filter>
+                <action android:name="org.thialfihar.android.apg.IApgService"/>
+            </intent-filter>
+        </service>  
         <provider
             android:readPermission="org.thialfihar.android.apg.permission.READ_KEY_DETAILS"
             android:name="org.thialfihar.android.apg.provider.DataProvider"

src/org/thialfihar/android/apg/ApgService.java

@@ -0,0 +1,76 @@
+package org.thialfihar.android.apg;
+
+import java.io.ByteArrayInputStream;
+import java.io.ByteArrayOutputStream;
+import java.io.InputStream;
+import java.io.OutputStream;
+
+import android.content.Intent;
+import android.os.IBinder;
+import android.util.Log;
+
+public class ApgService extends Service {
+    static String TAG = "ApgService";
+
+    @Override
+    public IBinder onBind(Intent intent) {
+        Log.d(TAG, "bound");
+        return mBinder;
+    }
+
+    private final IApgService.Stub mBinder = new IApgService.Stub() {
+
+        public String encrypt_with_passphrase(String msg, String passphrase) {
+            Preferences mPreferences = Preferences
+                    .getPreferences(getApplicationContext());
+            InputStream inStream = new ByteArrayInputStream(msg.getBytes());
+            InputData in = new InputData(inStream, 9999);
+            OutputStream out = new ByteArrayOutputStream();
+            long enc_keys[] = {};
+
+            Apg.initialize(getApplicationContext());
+            try {
+                Apg.encrypt(
+                        getApplicationContext(),
+                        in,
+                        out,
+                        true, // armored
+                        enc_keys, // encryption keys
+                        0, // signature key
+                        null, // signature passphrase
+                        null, // progress
+                        mPreferences.getDefaultEncryptionAlgorithm(),
+                        mPreferences.getDefaultHashAlgorithm(),
+                        Id.choice.compression.none, false, // mPreferences.getForceV3Signatures(),
+                        passphrase // passPhrase
+                        );
+            } catch (Exception e) {
+                Log.d(TAG, "Exception in encrypt");
+                e.printStackTrace();
+                return null;
+            }
+            Log.d(TAG, "Encrypted");
+            return out.toString();
+        }
+
+        public String decrypt_with_passphrase(String encrypted_msg,
+                String passphrase) {
+            InputStream inStream = new ByteArrayInputStream(encrypted_msg
+                    .getBytes());
+            InputData in = new InputData(inStream, 9999); // XXX what size in
+                                                          // second parameter?
+            OutputStream out = new ByteArrayOutputStream();
+            try {
+                Apg.decrypt(getApplicationContext(), in, out, passphrase, null, // progress
+                        true // symmetric
+                        );
+            } catch (Exception e) {
+                Log.d(TAG, "Exception in decrypt");
+                e.printStackTrace();
+                return null;
+            }
+
+            return out.toString();
+        }
+    };
+}

src/org/thialfihar/android/apg/IApgService.aidl

@@ -0,0 +1,6 @@
+package org.thialfihar.android.apg;
+
+interface IApgService {
+    String encrypt_with_passphrase(String msg, String passphrase);
+    String decrypt_with_passphrase(String encrypted_msg, String passphrase);
+}