diff --git a/APG-API-Lib/libs/android-support-v4.jar b/APG-API-Lib/libs/android-support-v4.jar
new file mode 100644
index 000000000..99e063b33
Binary files /dev/null and b/APG-API-Lib/libs/android-support-v4.jar differ
diff --git a/APG-API-Lib/src/org/thialfihar/android/apg/integration/ApgData.java b/APG-API-Lib/src/org/thialfihar/android/apg/integration/ApgData.java
index 538e591df..317f2c1c4 100644
--- a/APG-API-Lib/src/org/thialfihar/android/apg/integration/ApgData.java
+++ b/APG-API-Lib/src/org/thialfihar/android/apg/integration/ApgData.java
@@ -22,7 +22,8 @@ import java.util.Arrays;
 
 public class ApgData implements Serializable {
     private static final long serialVersionUID = 6314045536270848410L;
-    protected long mPublicKeyIds[] = null;
+    protected long[] mPublicKeyIds = null;
+    protected String[] mPublicUserIds = null;
     protected long mSecretKeyId = 0;
     protected String mSecretKeyUserId = null;
     protected boolean mSignatureSuccess = false;
@@ -38,7 +39,7 @@ public class ApgData implements Serializable {
         return mSecretKeyId;
     }
 
-    public void setPublicKeys(long keyIds[]) {
+    public void setPublicKeyIds(long[] keyIds) {
         mPublicKeyIds = keyIds;
     }
 
@@ -46,6 +47,14 @@ public class ApgData implements Serializable {
         return mPublicKeyIds;
     }
 
+    public void setPublicUserIds(String[] userIds) {
+        mPublicUserIds = userIds;
+    }
+
+    public String[] getPublicUserIds() {
+        return mPublicUserIds;
+    }
+
     public boolean hasSecretKey() {
         return mSecretKeyId != 0;
     }
diff --git a/APG-API-Lib/src/org/thialfihar/android/apg/integration/ApgIntentHelper.java b/APG-API-Lib/src/org/thialfihar/android/apg/integration/ApgIntentHelper.java
index 1b95e8986..27d5480fa 100644
--- a/APG-API-Lib/src/org/thialfihar/android/apg/integration/ApgIntentHelper.java
+++ b/APG-API-Lib/src/org/thialfihar/android/apg/integration/ApgIntentHelper.java
@@ -112,6 +112,22 @@ public class ApgIntentHelper {
         this.activity = activity;
     }
 
+    /**
+     * Start an activity.<br>
+     * This method is defined to allow different methods of activity starting for newer versions of
+     * Android and for compatibility library.
+     * 
+     * @param intent
+     *            Intent to start.
+     * @param code
+     *            Request code for the activity
+     * @see android.app.Activity#startActivityForResult(Intent, int)
+     * @see android.app.Fragment#startActivityForResult(Intent, int)
+     */
+    protected void startActivityForResult(Intent intent, int code) {
+        startActivityForResult(intent, code);
+    }
+
     /**
      * Open activity to scan qr code and import key in it
      * 
@@ -121,7 +137,7 @@ public class ApgIntentHelper {
         Intent intent = new Intent(ACTION_SCAN_QR_CODE);
         intent.putExtra(EXTRA_INTENT_VERSION, INTENT_VERSION);
         try {
-            activity.startActivityForResult(intent, -1);
+            startActivityForResult(intent, -1);
             return true;
         } catch (ActivityNotFoundException e) {
             activityNotFound();
@@ -146,7 +162,7 @@ public class ApgIntentHelper {
 
         intent.putExtra(EXTRA_INTENT_VERSION, INTENT_VERSION);
         try {
-            activity.startActivityForResult(intent, CREATE_KEY);
+            startActivityForResult(intent, CREATE_KEY);
             return true;
         } catch (ActivityNotFoundException e) {
             activityNotFound();
@@ -174,7 +190,7 @@ public class ApgIntentHelper {
         intent.putExtra(EXTRA_KEY_ID, keyId);
         intent.putExtra(EXTRA_INTENT_VERSION, INTENT_VERSION);
         try {
-            activity.startActivityForResult(intent, EDIT_KEY);
+            startActivityForResult(intent, EDIT_KEY);
             return true;
         } catch (ActivityNotFoundException e) {
             activityNotFound();
@@ -191,7 +207,7 @@ public class ApgIntentHelper {
         Intent intent = new Intent(ACTION_SELECT_SECRET_KEY);
         intent.putExtra(EXTRA_INTENT_VERSION, INTENT_VERSION);
         try {
-            activity.startActivityForResult(intent, SELECT_SECRET_KEY);
+            startActivityForResult(intent, SELECT_SECRET_KEY);
             return true;
         } catch (ActivityNotFoundException e) {
             activityNotFound();
@@ -225,7 +241,7 @@ public class ApgIntentHelper {
         intent.putExtra(EXTRA_ENCRYPTION_KEY_IDS, encryptionKeyIds);
         intent.putExtra(EXTRA_SIGNATURE_KEY_ID, signatureKeyId);
         try {
-            activity.startActivityForResult(intent, ENCRYPT_MESSAGE);
+            startActivityForResult(intent, ENCRYPT_MESSAGE);
             return true;
         } catch (ActivityNotFoundException e) {
             activityNotFound();
@@ -255,7 +271,7 @@ public class ApgIntentHelper {
         }
         try {
             intent.putExtra(EXTRA_TEXT, data);
-            activity.startActivityForResult(intent, DECRYPT_MESSAGE);
+            startActivityForResult(intent, DECRYPT_MESSAGE);
             return true;
         } catch (ActivityNotFoundException e) {
             activityNotFound();
@@ -294,15 +310,16 @@ public class ApgIntentHelper {
             break;
         case SELECT_PUBLIC_KEYS:
             if (resultCode != Activity.RESULT_OK || data == null) {
-                apgData.setPublicKeys(null);
+                apgData.setPublicKeyIds(null);
                 break;
             }
-            apgData.setPublicKeys(data.getLongArrayExtra(RESULT_EXTRA_MASTER_KEY_IDS));
+            apgData.setPublicKeyIds(data.getLongArrayExtra(RESULT_EXTRA_MASTER_KEY_IDS));
+            apgData.setPublicUserIds(data.getStringArrayExtra(RESULT_EXTRA_USER_IDS));
 
             break;
         case ENCRYPT_MESSAGE:
             if (resultCode != Activity.RESULT_OK || data == null) {
-                apgData.setPublicKeys(null);
+                apgData.setPublicKeyIds(null);
                 break;
             }
             apgData.setEncryptedData(data.getStringExtra(EXTRA_ENCRYPTED_MESSAGE));
@@ -363,7 +380,7 @@ public class ApgIntentHelper {
         intent.putExtra(EXTRA_SELECTION, initialKeyIds);
 
         try {
-            activity.startActivityForResult(intent, SELECT_PUBLIC_KEYS);
+            startActivityForResult(intent, SELECT_PUBLIC_KEYS);
             return true;
         } catch (ActivityNotFoundException e) {
             activityNotFound();
diff --git a/APG-API-Lib/src/org/thialfihar/android/apg/integration/ApgIntentHelperSupportV4.java b/APG-API-Lib/src/org/thialfihar/android/apg/integration/ApgIntentHelperSupportV4.java
new file mode 100644
index 000000000..8a64a925a
--- /dev/null
+++ b/APG-API-Lib/src/org/thialfihar/android/apg/integration/ApgIntentHelperSupportV4.java
@@ -0,0 +1,43 @@
+/*
+ * Copyright (C) 2012 Dominik Schürmann <dominik@dominikschuermann.de>
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.thialfihar.android.apg.integration;
+
+import android.content.Intent;
+import android.support.v4.app.Fragment;
+
+/**
+ * ApgIntentHelper for the V4 Android compatibility package.
+ */
+public final class ApgIntentHelperSupportV4 extends ApgIntentHelper {
+
+    private final Fragment fragment;
+
+    /**
+     * @param fragment
+     *            Fragment to handle activity response.
+     */
+    public ApgIntentHelperSupportV4(Fragment fragment) {
+        super(fragment.getActivity());
+        this.fragment = fragment;
+    }
+
+    @Override
+    protected void startActivityForResult(Intent intent, int code) {
+        fragment.startActivityForResult(intent, code);
+    }
+
+}
\ No newline at end of file
diff --git a/APG-API-Lib/src/org/thialfihar/android/apg/integration/ApgIntentHelperV30.java b/APG-API-Lib/src/org/thialfihar/android/apg/integration/ApgIntentHelperV30.java
new file mode 100644
index 000000000..4c1fbea40
--- /dev/null
+++ b/APG-API-Lib/src/org/thialfihar/android/apg/integration/ApgIntentHelperV30.java
@@ -0,0 +1,46 @@
+/*
+ * Copyright (C) 2012 Dominik Schürmann <dominik@dominikschuermann.de>
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.thialfihar.android.apg.integration;
+
+import android.annotation.TargetApi;
+import android.app.Fragment;
+import android.content.Intent;
+import android.os.Build;
+
+/**
+ * ApgIntentHelper for Android version 3.0 and beyond.
+ */
+@TargetApi(Build.VERSION_CODES.HONEYCOMB)
+public final class ApgIntentHelperV30 extends ApgIntentHelper {
+
+    private final Fragment fragment;
+
+    /**
+     * @param fragment
+     *            Fragment to handle activity response.
+     */
+    public ApgIntentHelperV30(Fragment fragment) {
+        super(fragment.getActivity());
+        this.fragment = fragment;
+    }
+
+    @Override
+    protected void startActivityForResult(Intent intent, int code) {
+        fragment.startActivityForResult(intent, code);
+    }
+
+}
\ No newline at end of file
diff --git a/APG/src/org/thialfihar/android/apg/provider/ApgProvider.java b/APG/src/org/thialfihar/android/apg/provider/ApgProvider.java
index a5bb26507..88cb3df21 100644
--- a/APG/src/org/thialfihar/android/apg/provider/ApgProvider.java
+++ b/APG/src/org/thialfihar/android/apg/provider/ApgProvider.java
@@ -115,6 +115,9 @@ public class ApgProvider extends ContentProvider {
                 + ApgContract.PATH_BY_KEY_ID + "/*", PUBLIC_KEY_RING_BY_KEY_ID);
         matcher.addURI(authority, ApgContract.BASE_KEY_RINGS + "/" + ApgContract.PATH_PUBLIC + "/"
                 + ApgContract.PATH_BY_EMAILS + "/*", PUBLIC_KEY_RING_BY_EMAILS);
+        matcher.addURI(authority, ApgContract.BASE_KEY_RINGS + "/" + ApgContract.PATH_PUBLIC + "/"
+                + ApgContract.PATH_BY_EMAILS, PUBLIC_KEY_RING_BY_EMAILS); // without emails
+                                                                          // specified
         matcher.addURI(authority, ApgContract.BASE_KEY_RINGS + "/" + ApgContract.PATH_PUBLIC + "/"
                 + ApgContract.PATH_BY_LIKE_EMAIL + "/*", PUBLIC_KEY_RING_BY_LIKE_EMAIL);
 
@@ -167,6 +170,9 @@ public class ApgProvider extends ContentProvider {
                 + ApgContract.PATH_BY_KEY_ID + "/*", SECRET_KEY_RING_BY_KEY_ID);
         matcher.addURI(authority, ApgContract.BASE_KEY_RINGS + "/" + ApgContract.PATH_SECRET + "/"
                 + ApgContract.PATH_BY_EMAILS + "/*", SECRET_KEY_RING_BY_EMAILS);
+        matcher.addURI(authority, ApgContract.BASE_KEY_RINGS + "/" + ApgContract.PATH_SECRET + "/"
+                + ApgContract.PATH_BY_EMAILS, SECRET_KEY_RING_BY_EMAILS); // without emails
+                                                                          // specified
         matcher.addURI(authority, ApgContract.BASE_KEY_RINGS + "/" + ApgContract.PATH_SECRET + "/"
                 + ApgContract.PATH_BY_LIKE_EMAIL + "/*", SECRET_KEY_RING_BY_LIKE_EMAIL);