Refactor MasterSecret initialization, access, and timeout paths.

1) Consolidate all of the KeyCachingService interaction into a single
   mixin. Activities extend delegates which call through to the mixin.

2) Switch Activity increment/decrement triggers from onStop to onPause
   in order to account for some screen locks that don't stop activities.

src/org/thoughtcrime/securesms/ApplicationPreferencesActivity.java

@@ -30,9 +30,6 @@ import android.provider.ContactsContract;
 import android.util.Log;
 import android.widget.Toast;
 
-import com.actionbarsherlock.app.SherlockPreferenceActivity;
-import com.actionbarsherlock.view.MenuItem;
-
 import org.thoughtcrime.securesms.contacts.ContactAccessor;
 import org.thoughtcrime.securesms.contacts.ContactIdentityManager;
 import org.thoughtcrime.securesms.crypto.IdentityKey;
@@ -43,6 +40,8 @@ import org.thoughtcrime.securesms.util.Dialogs;
 import org.thoughtcrime.securesms.util.MemoryCleaner;
 import org.thoughtcrime.securesms.util.Trimmer;
 
+import com.actionbarsherlock.view.MenuItem;
+
 import java.util.List;
 
 /**
@@ -52,7 +51,7 @@ import java.util.List;
  *
  */
 
-public class ApplicationPreferencesActivity extends SherlockPreferenceActivity {
+public class ApplicationPreferencesActivity extends PassphraseRequiredSherlockPreferenceActivity {
 
   private static final int   PICK_IDENTITY_CONTACT        = 1;
   private static final int   IMPORT_IDENTITY_ID           = 2;
@@ -119,19 +118,9 @@ public class ApplicationPreferencesActivity extends SherlockPreferenceActivity {
   }
 
   @Override
-  public void onStart() {
-    super.onStart();
-    Intent intent = new Intent(this, KeyCachingService.class);
-    intent.setAction(KeyCachingService.ACTIVITY_START_EVENT);
-    startService(intent);
-  }
-
-  @Override
-  public void onStop() {
-    super.onStop();
-    Intent intent = new Intent(this, KeyCachingService.class);
-    intent.setAction(KeyCachingService.ACTIVITY_STOP_EVENT);
-    startService(intent);
+  public void onDestroy() {
+    MemoryCleaner.clean((MasterSecret)getIntent().getParcelableExtra("master_secret"));
+    super.onDestroy();
   }
 
   @Override
@@ -146,12 +135,6 @@ public class ApplicationPreferencesActivity extends SherlockPreferenceActivity {
     }
   }
 
-  @Override
-  public void onDestroy() {
-    MemoryCleaner.clean((MasterSecret)getIntent().getParcelableExtra("master_secret"));
-    super.onDestroy();
-  }
-
   @Override
   public boolean onOptionsItemSelected(MenuItem item) {
     switch (item.getItemId()) {
@@ -237,6 +220,7 @@ public class ApplicationPreferencesActivity extends SherlockPreferenceActivity {
   }
 
   private class IdentityPreferenceClickListener implements Preference.OnPreferenceClickListener {
+    @Override
     public boolean onPreferenceClick(Preference preference) {
       Intent intent = new Intent(Intent.ACTION_PICK);
       intent.setType(ContactsContract.Contacts.CONTENT_TYPE);
@@ -246,6 +230,7 @@ public class ApplicationPreferencesActivity extends SherlockPreferenceActivity {
   }
 
   private class ViewMyIdentityClickListener implements Preference.OnPreferenceClickListener {
+    @Override
     public boolean onPreferenceClick(Preference preference) {
       Intent viewIdentityIntent = new Intent(ApplicationPreferencesActivity.this, ViewIdentityActivity.class);
       viewIdentityIntent.putExtra("identity_key", IdentityKeyUtil.getIdentityKey(ApplicationPreferencesActivity.this));
@@ -256,6 +241,7 @@ public class ApplicationPreferencesActivity extends SherlockPreferenceActivity {
   }
 
   private class ExportMyIdentityClickListener implements Preference.OnPreferenceClickListener {
+    @Override
     public boolean onPreferenceClick(Preference preference) {
       if (!IdentityKeyUtil.hasIdentityKey(ApplicationPreferencesActivity.this)) {
         Toast.makeText(ApplicationPreferencesActivity.this,
@@ -287,6 +273,7 @@ public class ApplicationPreferencesActivity extends SherlockPreferenceActivity {
   }
 
   private class ImportContactIdentityClickListener implements Preference.OnPreferenceClickListener {
+    @Override
     public boolean onPreferenceClick(Preference preference) {
       MasterSecret masterSecret = (MasterSecret)getIntent().getParcelableExtra("master_secret");
 
@@ -305,6 +292,7 @@ public class ApplicationPreferencesActivity extends SherlockPreferenceActivity {
   }
 
   private class ManageIdentitiesClickListener implements Preference.OnPreferenceClickListener {
+    @Override
     public boolean onPreferenceClick(Preference preference) {
       MasterSecret masterSecret = (MasterSecret)getIntent().getParcelableExtra("master_secret");
 
@@ -323,6 +311,7 @@ public class ApplicationPreferencesActivity extends SherlockPreferenceActivity {
   }
 
   private class ChangePassphraseClickListener implements Preference.OnPreferenceClickListener {
+    @Override
     public boolean onPreferenceClick(Preference preference) {
       SharedPreferences settings = getSharedPreferences(KeyCachingService.PREFERENCES_NAME, 0);
 
@@ -382,7 +371,7 @@ public class ApplicationPreferencesActivity extends SherlockPreferenceActivity {
         Log.w("ApplicationPreferencesActivity", nfe);
         return false;
       }
-      
+
       if (Integer.parseInt((String)newValue) < 1) {
         return false;
       }
@@ -393,5 +382,4 @@ public class ApplicationPreferencesActivity extends SherlockPreferenceActivity {
     }
 
   }
-
 }

src/org/thoughtcrime/securesms/AutoInitiateActivity.java

@@ -24,8 +24,6 @@ import android.util.Log;
 import android.view.View;
 import android.widget.Button;
 
-import com.actionbarsherlock.app.SherlockActivity;
-
 import org.thoughtcrime.securesms.crypto.KeyExchangeInitiator;
 import org.thoughtcrime.securesms.crypto.MasterSecret;
 import org.thoughtcrime.securesms.database.LocalKeyRecord;
@@ -42,7 +40,7 @@ import org.thoughtcrime.securesms.util.MemoryCleaner;
  * @author Moxie Marlinspike
  *
  */
-public class AutoInitiateActivity extends SherlockActivity {
+public class AutoInitiateActivity extends PassphraseRequiredSherlockActivity {
 
   private long threadId;
   private Recipient recipient;
@@ -77,12 +75,14 @@ public class AutoInitiateActivity extends SherlockActivity {
   }
 
   private class OkListener implements View.OnClickListener {
+    @Override
     public void onClick(View v) {
       initiateKeyExchange();
     }
   }
 
   private class CancelListener implements View.OnClickListener {
+    @Override
     public void onClick(View v) {
       Log.w("AutoInitiateActivity", "Exempting threadID: " + threadId);
       exemptThread(AutoInitiateActivity.this, threadId);
@@ -114,5 +114,4 @@ public class AutoInitiateActivity extends SherlockActivity {
       (new RemoteKeyRecord(context,recipient).getCurrentRemoteKey() == null) &&
       (new LocalKeyRecord(context, masterSecret, recipient).getCurrentKeyPair() == null);
   }
-
 }

src/org/thoughtcrime/securesms/ContactSelectionActivity.java

@@ -22,17 +22,15 @@ import android.support.v4.app.Fragment;
 import android.support.v4.app.FragmentManager;
 import android.support.v4.app.FragmentTransaction;
 
+import org.thoughtcrime.securesms.recipients.Recipients;
+
 import com.actionbarsherlock.app.ActionBar;
 import com.actionbarsherlock.app.ActionBar.Tab;
 import com.actionbarsherlock.app.ActionBar.TabListener;
-import com.actionbarsherlock.app.SherlockFragmentActivity;
 import com.actionbarsherlock.view.Menu;
 import com.actionbarsherlock.view.MenuInflater;
 import com.actionbarsherlock.view.MenuItem;
 
-import org.thoughtcrime.securesms.recipients.Recipients;
-import org.thoughtcrime.securesms.service.KeyCachingService;
-
 /**
  * Activity container for selecting a list of contacts.  Provides a tab frame for
  * contact, group, and "recent contact" activity tabs.  Used by ComposeMessageActivity
@@ -41,7 +39,7 @@ import org.thoughtcrime.securesms.service.KeyCachingService;
  * @author Moxie Marlinspike
  *
  */
-public class ContactSelectionActivity extends SherlockFragmentActivity {
+public class ContactSelectionActivity extends PassphraseRequiredSherlockFragmentActivity {
 
   private ContactSelectionListFragment contactsFragment;
   private ContactSelectionGroupsFragment groupsFragment;
@@ -64,18 +62,6 @@ public class ContactSelectionActivity extends SherlockFragmentActivity {
     setupRecentTab();
   }
 
-  @Override
-  protected void onStart() {
-    super.onStart();
-    registerPassphraseActivityStarted();
-  }
-
-  @Override
-  protected void onStop() {
-    super.onStop();
-    registerPassphraseActivityStopped();
-  }
-
   @Override
   public boolean onCreateOptionsMenu(Menu menu) {
     MenuInflater inflater = this.getSupportMenuInflater();
@@ -160,19 +146,4 @@ public class ContactSelectionActivity extends SherlockFragmentActivity {
     recentTab.setIcon(R.drawable.ic_tab_recent);
     this.getSupportActionBar().addTab(recentTab);
   }
-
-  private void registerPassphraseActivityStarted() {
-    Intent intent = new Intent(this, KeyCachingService.class);
-    intent.setAction(KeyCachingService.ACTIVITY_START_EVENT);
-    startService(intent);
-  }
-
-  private void registerPassphraseActivityStopped() {
-    Intent intent = new Intent(this, KeyCachingService.class);
-    intent.setAction(KeyCachingService.ACTIVITY_STOP_EVENT);
-    startService(intent);
-  }
-
-
-
 }

src/org/thoughtcrime/securesms/ConversationActivity.java

@@ -75,7 +75,6 @@ import org.thoughtcrime.securesms.util.Util;
 
 import ws.com.google.android.mms.MmsException;
 
-import com.actionbarsherlock.app.SherlockFragmentActivity;
 import com.actionbarsherlock.view.Menu;
 import com.actionbarsherlock.view.MenuInflater;
 import com.actionbarsherlock.view.MenuItem;
@@ -91,7 +90,7 @@ import java.util.List;
  * @author Moxie Marlinspike
  *
  */
-public class ConversationActivity extends SherlockFragmentActivity
+public class ConversationActivity extends PassphraseRequiredSherlockFragmentActivity
     implements ConversationFragment.ConversationFragmentListener
   {
 
@@ -116,7 +115,6 @@ public class ConversationActivity extends SherlockFragmentActivity
 
   private AttachmentTypeSelectorAdapter attachmentAdapter;
   private AttachmentManager attachmentManager;
-  private BroadcastReceiver killActivityReceiver;
   private BroadcastReceiver securityUpdateReceiver;
 
   private Recipients recipients;
@@ -161,20 +159,10 @@ public class ConversationActivity extends SherlockFragmentActivity
 
     if (!isExistingConversation())
       initializeRecipientsInput();
-
-    registerPassphraseActivityStarted();
-  }
-
-  @Override
-  protected void onStop() {
-    super.onStop();
-
-    registerPassphraseActivityStopped();
   }
 
   @Override
   protected void onDestroy() {
-    unregisterReceiver(killActivityReceiver);
     unregisterReceiver(securityUpdateReceiver);
     saveDraft();
     MemoryCleaner.clean(masterSecret);
@@ -518,13 +506,6 @@ public class ConversationActivity extends SherlockFragmentActivity
 
 
   private void initializeReceivers() {
-    killActivityReceiver   = new BroadcastReceiver() {
-      @Override
-      public void onReceive(Context context, Intent intent) {
-        finish();
-      }
-    };
-
     securityUpdateReceiver = new BroadcastReceiver() {
       @Override
       public void onReceive(Context context, Intent intent) {
@@ -539,10 +520,6 @@ public class ConversationActivity extends SherlockFragmentActivity
       }
     };
 
-    registerReceiver(killActivityReceiver,
-                     new IntentFilter(KeyCachingService.CLEAR_KEY_EVENT),
-                     KeyCachingService.KEY_PERMISSION, null);
-
     registerReceiver(securityUpdateReceiver,
                      new IntentFilter(KeyExchangeProcessor.SECURITY_UPDATE_EVENT),
                      KeyCachingService.KEY_PERMISSION, null);
@@ -767,18 +744,6 @@ public class ConversationActivity extends SherlockFragmentActivity
     }
   }
 
-  private void registerPassphraseActivityStarted() {
-    Intent intent = new Intent(this, KeyCachingService.class);
-    intent.setAction(KeyCachingService.ACTIVITY_START_EVENT);
-    startService(intent);
-  }
-
-  private void registerPassphraseActivityStopped() {
-    Intent intent = new Intent(this, KeyCachingService.class);
-    intent.setAction(KeyCachingService.ACTIVITY_STOP_EVENT);
-    startService(intent);
-  }
-
   // Listeners
 
   private class AddRecipientButtonListener implements OnClickListener {

src/org/thoughtcrime/securesms/ConversationListActivity.java

@@ -1,18 +1,12 @@
 package org.thoughtcrime.securesms;
 
-import android.app.NotificationManager;
-import android.content.BroadcastReceiver;
-import android.content.ComponentName;
 import android.content.Context;
 import android.content.Intent;
-import android.content.IntentFilter;
-import android.content.ServiceConnection;
 import android.content.SharedPreferences;
 import android.database.ContentObserver;
 import android.net.Uri;
 import android.os.Build;
 import android.os.Bundle;
-import android.os.IBinder;
 import android.os.Parcelable;
 import android.provider.ContactsContract;
 import android.util.Log;
@@ -31,20 +25,17 @@ import org.thoughtcrime.securesms.service.KeyCachingService;
 import org.thoughtcrime.securesms.service.SendReceiveService;
 import org.thoughtcrime.securesms.util.MemoryCleaner;
 
-import com.actionbarsherlock.app.SherlockFragmentActivity;
 import com.actionbarsherlock.view.Menu;
 import com.actionbarsherlock.view.MenuInflater;
 import com.actionbarsherlock.view.MenuItem;
 
-public class ConversationListActivity extends SherlockFragmentActivity
+public class ConversationListActivity extends PassphraseRequiredSherlockFragmentActivity
     implements ConversationListFragment.ConversationSelectedListener
   {
 
   private ConversationListFragment fragment;
   private MasterSecret masterSecret;
 
-  private BroadcastReceiver killActivityReceiver;
-  private BroadcastReceiver newKeyReceiver;
   private ApplicationMigrationManager migrationManager;
 
   private boolean havePromptedForPassphrase = false;
@@ -56,7 +47,6 @@ public class ConversationListActivity extends SherlockFragmentActivity
     setContentView(R.layout.conversation_list_activity);
     getSupportActionBar().setTitle("TextSecure");
 
-    initializeKillReceiver();
     initializeSenderReceiverService();
     initializeResources();
     initializeContactUpdatesReceiver();
@@ -65,51 +55,71 @@ public class ConversationListActivity extends SherlockFragmentActivity
   @Override
   protected void onNewIntent(Intent intent) {
     super.onNewIntent(intent);
-    createConversationIfNecessary(intent);
-  }
-
-  @Override
-  public void onPause() {
-    super.onPause();
-
-    if (newKeyReceiver != null) {
-      unregisterReceiver(newKeyReceiver);
-      newKeyReceiver = null;
-    }
-
-    isVisible = false;
+    this.setIntent(intent);
   }
 
   @Override
   public void onResume() {
     super.onResume();
 
-    clearNotifications();
-    initializeKeyCachingServiceRegistration();
     isVisible = true;
   }
 
   @Override
-  public void onStart() {
-    super.onStart();
-    registerPassphraseActivityStarted();
+  public void onPause() {
+    super.onPause();
+
+    isVisible = false;
   }
 
   @Override
   public void onStop() {
     super.onStop();
     havePromptedForPassphrase = false;
-    registerPassphraseActivityStopped();
   }
 
   @Override
   public void onDestroy() {
-    Log.w("SecureSMS", "onDestroy...");
-    unregisterReceiver(killActivityReceiver);
+    Log.w("ConversationListActivity", "onDestroy...");
     MemoryCleaner.clean(masterSecret);
     super.onDestroy();
   }
 
+  @Override
+  public void onMasterSecretCleared() {
+    this.masterSecret = null;
+    this.fragment.setMasterSecret(null);
+    this.invalidateOptionsMenu();
+
+    if (!havePromptedForPassphrase && isVisible) {
+      promptForPassphrase();
+    }
+  }
+
+  @Override
+  public void onNewMasterSecret(MasterSecret masterSecret) {
+    this.masterSecret = masterSecret;
+
+    if (masterSecret != null) {
+      if (!IdentityKeyUtil.hasIdentityKey(this)) {
+        new Thread(new IdentityKeyInitializer()).start();
+      }
+
+      if (!MasterSecretUtil.hasAsymmericMasterSecret(this)) {
+        new Thread(new AsymmetricMasteSecretInitializer()).start();
+      }
+
+      if (!isDatabaseMigrated()) initializeDatabaseMigration();
+      else                       DecryptingQueue.schedulePendingDecrypts(this, masterSecret);
+    }
+
+    this.fragment.setMasterSecret(masterSecret);
+    this.invalidateOptionsMenu();
+    this.havePromptedForPassphrase = false;
+    createConversationIfNecessary(this.getIntent());
+  }
+
+
   @Override
   public boolean onPrepareOptionsMenu(Menu menu) {
     Log.w("ConversationListActivity", "onPrepareOptionsMenu...");
@@ -190,11 +200,8 @@ public class ConversationListActivity extends SherlockFragmentActivity
     ApplicationExportListener listener = new ApplicationExportManager.ApplicationExportListener() {
       @Override
       public void onPrepareForImport() {
-        initializeWithMasterSecret(null);
-
-        Intent clearKeyIntent = new Intent(KeyCachingService.CLEAR_KEY_ACTION, null,
-                                           ConversationListActivity.this, KeyCachingService.class);
-        startService(clearKeyIntent);
+        onMasterSecretCleared();
+        handleClearPassphrase();
       }
     };
 
@@ -208,45 +215,6 @@ public class ConversationListActivity extends SherlockFragmentActivity
     startService(intent);
   }
 
-  private void initializeWithMasterSecret(MasterSecret masterSecret) {
-    this.masterSecret = masterSecret;
-
-    if (masterSecret != null) {
-      if (!IdentityKeyUtil.hasIdentityKey(this)) {
-        new Thread(new IdentityKeyInitializer()).start();
-      }
-
-      if (!MasterSecretUtil.hasAsymmericMasterSecret(this)) {
-        new Thread(new AsymmetricMasteSecretInitializer()).start();
-      }
-
-      if (!isDatabaseMigrated()) initializeDatabaseMigration();
-      else                       DecryptingQueue.schedulePendingDecrypts(this, masterSecret);
-    }
-
-    this.fragment.setMasterSecret(masterSecret);
-    this.invalidateOptionsMenu();
-    createConversationIfNecessary(this.getIntent());
-  }
-
-  private void initializeKillReceiver() {
-    this.killActivityReceiver = new BroadcastReceiver() {
-      @Override
-      public void onReceive(Context context, Intent intent) {
-        ConversationListActivity.this.masterSecret = null;
-        fragment.setMasterSecret(null);
-
-        if (isVisible) {
-          promptForPassphrase();
-        }
-      }
-    };
-
-    registerReceiver(this.killActivityReceiver,
-                     new IntentFilter(KeyCachingService.CLEAR_KEY_EVENT),
-                     KeyCachingService.KEY_PERMISSION, null);
-  }
-
   private void initializeContactUpdatesReceiver() {
     ContentObserver observer = new ContentObserver(null) {
       @Override
@@ -288,26 +256,10 @@ public class ConversationListActivity extends SherlockFragmentActivity
     }
   }
 
-  private void initializeKeyCachingServiceRegistration() {
-    Log.w("ConversationListActivity", "Checking caching service...");
-    this.newKeyReceiver = new BroadcastReceiver() {
-      @Override
-      public void onReceive(Context context, Intent intent) {
-        Log.w("ConversationListActivity", "Got a key broadcast...");
-        initializeWithMasterSecret((MasterSecret)intent.getParcelableExtra("master_secret"));
-      }
-    };
-
-    IntentFilter filter = new IntentFilter(KeyCachingService.NEW_KEY_EVENT);
-    registerReceiver(newKeyReceiver, filter, KeyCachingService.KEY_PERMISSION, null);
-
-    Intent bindIntent = new Intent(this, KeyCachingService.class);
-    bindService(bindIntent, serviceConnection, Context.BIND_AUTO_CREATE);
-  }
-
   private void initializeResources() {
     if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.HONEYCOMB) {
-      getWindow().setFlags(WindowManager.LayoutParams.FLAG_SECURE, WindowManager.LayoutParams.FLAG_SECURE);
+      getWindow().setFlags(WindowManager.LayoutParams.FLAG_SECURE,
+                           WindowManager.LayoutParams.FLAG_SECURE);
     }
 
     this.fragment = (ConversationListFragment)this.getSupportFragmentManager()
@@ -319,13 +271,6 @@ public class ConversationListActivity extends SherlockFragmentActivity
             .getBoolean("migrated", false);
   }
 
-  private void clearNotifications() {
-    NotificationManager manager =
-        (NotificationManager)getSystemService(Context.NOTIFICATION_SERVICE);
-
-    manager.cancel(KeyCachingService.NOTIFICATION_ID);
-  }
-
   private void createConversationIfNecessary(Intent intent) {
     long thread           = intent.getLongExtra("thread_id", -1L);
     String type           = intent.getType();
@@ -364,43 +309,6 @@ public class ConversationListActivity extends SherlockFragmentActivity
     }
   }
 
-  private void registerPassphraseActivityStarted() {
-    Intent intent = new Intent(this, KeyCachingService.class);
-    intent.setAction(KeyCachingService.ACTIVITY_START_EVENT);
-    startService(intent);
-  }
-
-  private void registerPassphraseActivityStopped() {
-    Intent intent = new Intent(this, KeyCachingService.class);
-    intent.setAction(KeyCachingService.ACTIVITY_STOP_EVENT);
-    startService(intent);
-  }
-
-  private ServiceConnection serviceConnection = new ServiceConnection() {
-    @Override
-    public void onServiceConnected(ComponentName className, IBinder service) {
-      KeyCachingService keyCachingService  = ((KeyCachingService.KeyCachingBinder)service).getService();
-      MasterSecret masterSecret            = keyCachingService.getMasterSecret();
-
-      initializeWithMasterSecret(masterSecret);
-
-      if (masterSecret == null && !havePromptedForPassphrase)
-        promptForPassphrase();
-
-      Intent cachingIntent = new Intent(ConversationListActivity.this, KeyCachingService.class);
-      startService(cachingIntent);
-
-      try {
-        ConversationListActivity.this.unbindService(this);
-      } catch (IllegalArgumentException iae) {
-        Log.w("SecureSMS", iae);
-      }
-    }
-
-    @Override
-    public void onServiceDisconnected(ComponentName name) {}
-  };
-
   private class IdentityKeyInitializer implements Runnable {
     @Override
     public void run() {
@@ -414,5 +322,4 @@ public class ConversationListActivity extends SherlockFragmentActivity
       MasterSecretUtil.generateAsymmetricMasterSecret(ConversationListActivity.this, masterSecret);
     }
   }
-
 }

src/org/thoughtcrime/securesms/KeyScanningActivity.java

@@ -19,23 +19,22 @@ package org.thoughtcrime.securesms;
 import android.content.Intent;
 import android.widget.Toast;
 
-import com.actionbarsherlock.app.SherlockActivity;
+import org.thoughtcrime.securesms.crypto.SerializableKey;
+import org.thoughtcrime.securesms.util.Base64;
+import org.thoughtcrime.securesms.util.Dialogs;
+
 import com.actionbarsherlock.view.Menu;
 import com.actionbarsherlock.view.MenuInflater;
 import com.actionbarsherlock.view.MenuItem;
 import com.google.zxing.integration.android.IntentIntegrator;
 import com.google.zxing.integration.android.IntentResult;
 
-import org.thoughtcrime.securesms.crypto.SerializableKey;
-import org.thoughtcrime.securesms.util.Base64;
-import org.thoughtcrime.securesms.util.Dialogs;
-
 /**
  * Activity for initiating/receiving key QR code scans.
  *
  * @author Moxie Marlinspike
  */
-public abstract class KeyScanningActivity extends SherlockActivity {
+public abstract class KeyScanningActivity extends PassphraseRequiredSherlockActivity {
 
   @Override
   public boolean onPrepareOptionsMenu(Menu menu) {

src/org/thoughtcrime/securesms/PassphraseRequiredActivity.java

@@ -0,0 +1,8 @@
+package org.thoughtcrime.securesms;
+
+import org.thoughtcrime.securesms.crypto.MasterSecret;
+
+public interface PassphraseRequiredActivity {
+  public void onMasterSecretCleared();
+  public void onNewMasterSecret(MasterSecret masterSecret);
+}

src/org/thoughtcrime/securesms/PassphraseRequiredMixin.java

@@ -0,0 +1,128 @@
+package org.thoughtcrime.securesms;
+
+import android.content.BroadcastReceiver;
+import android.content.ComponentName;
+import android.content.Context;
+import android.content.Intent;
+import android.content.IntentFilter;
+import android.content.ServiceConnection;
+import android.os.IBinder;
+
+import org.thoughtcrime.securesms.crypto.MasterSecret;
+import org.thoughtcrime.securesms.service.KeyCachingService;
+
+
+public class PassphraseRequiredMixin {
+
+  private KeyCachingServiceConnection serviceConnection;
+  private BroadcastReceiver clearKeyReceiver;
+  private BroadcastReceiver newKeyReceiver;
+
+  public void onCreate(Context context, PassphraseRequiredActivity activity) {
+    initializeClearKeyReceiver(context, activity);
+  }
+
+  public void onResume(Context context, PassphraseRequiredActivity activity) {
+    initializeNewKeyReceiver(context, activity);
+    initializeServiceConnection(context, activity);
+    KeyCachingService.registerPassphraseActivityStarted(context);
+  }
+
+  public void onPause(Context context, PassphraseRequiredActivity activity) {
+    removeNewKeyReceiver(context);
+    removeServiceConnection(context);
+    KeyCachingService.registerPassphraseActivityStopped(context);
+  }
+
+  public void onDestroy(Context context, PassphraseRequiredActivity activity) {
+    removeClearKeyReceiver(context);
+  }
+
+  private void initializeClearKeyReceiver(Context context, final PassphraseRequiredActivity activity) {
+    this.clearKeyReceiver = new BroadcastReceiver() {
+      @Override
+      public void onReceive(Context context, Intent intent) {
+        activity.onMasterSecretCleared();
+      }
+    };
+
+    IntentFilter filter = new IntentFilter(KeyCachingService.CLEAR_KEY_EVENT);
+    context.registerReceiver(clearKeyReceiver, filter, KeyCachingService.KEY_PERMISSION, null);
+  }
+
+  private void initializeNewKeyReceiver(Context context, final PassphraseRequiredActivity activity) {
+    this.newKeyReceiver = new BroadcastReceiver() {
+      @Override
+      public void onReceive(Context context, Intent intent) {
+        activity.onNewMasterSecret((MasterSecret)intent.getParcelableExtra("master_secret"));
+      }
+    };
+
+    IntentFilter filter = new IntentFilter(KeyCachingService.NEW_KEY_EVENT);
+    context.registerReceiver(newKeyReceiver, filter, KeyCachingService.KEY_PERMISSION, null);
+  }
+
+  private void initializeServiceConnection(Context context, PassphraseRequiredActivity activity) {
+    Intent cachingIntent = new Intent(context, KeyCachingService.class);
+    context.startService(cachingIntent);
+
+    this.serviceConnection = new KeyCachingServiceConnection(activity);
+
+    Intent bindIntent = new Intent(context, KeyCachingService.class);
+    context.bindService(bindIntent, serviceConnection, Context.BIND_AUTO_CREATE);
+  }
+
+  private void removeClearKeyReceiver(Context context) {
+    if (clearKeyReceiver != null) {
+      context.unregisterReceiver(clearKeyReceiver);
+      clearKeyReceiver = null;
+    }
+  }
+
+  private void removeNewKeyReceiver(Context context) {
+    if (newKeyReceiver != null) {
+      context.unregisterReceiver(newKeyReceiver);
+      newKeyReceiver = null;
+    }
+  }
+
+  private void removeServiceConnection(Context context) {
+    if (this.serviceConnection != null && this.serviceConnection.isBound()) {
+      context.unbindService(this.serviceConnection);
+    }
+  }
+
+  private static class KeyCachingServiceConnection implements ServiceConnection {
+    private final PassphraseRequiredActivity activity;
+
+    private boolean isBound;
+
+    public KeyCachingServiceConnection(PassphraseRequiredActivity activity) {
+      this.activity = activity;
+      this.isBound  = false;
+    }
+
+    @Override
+    public void onServiceConnected(ComponentName name, IBinder service) {
+      KeyCachingService keyCachingService  = ((KeyCachingService.KeyCachingBinder)service).getService();
+      MasterSecret masterSecret            = keyCachingService.getMasterSecret();
+      this.isBound                         = true;
+
+      if (masterSecret == null) {
+        activity.onMasterSecretCleared();
+      } else {
+        activity.onNewMasterSecret(masterSecret);
+      }
+    }
+
+    @Override
+    public void onServiceDisconnected(ComponentName name) {
+      this.isBound  = false;
+    }
+
+    public boolean isBound() {
+      return this.isBound;
+    }
+  }
+
+}

src/org/thoughtcrime/securesms/PassphraseRequiredSherlockActivity.java

@@ -0,0 +1,45 @@
+package org.thoughtcrime.securesms;
+
+import android.os.Bundle;
+
+import org.thoughtcrime.securesms.crypto.MasterSecret;
+
+import com.actionbarsherlock.app.SherlockActivity;
+
+public class PassphraseRequiredSherlockActivity extends SherlockActivity implements PassphraseRequiredActivity {
+
+  private final PassphraseRequiredMixin delegate = new PassphraseRequiredMixin();
+
+  @Override
+  protected void onCreate(Bundle savedInstanceState) {
+    super.onCreate(savedInstanceState);
+    delegate.onCreate(this, this);
+  }
+
+  @Override
+  protected void onResume() {
+    super.onResume();
+    delegate.onResume(this, this);
+  }
+
+  @Override
+  protected void onPause() {
+    super.onPause();
+    delegate.onPause(this, this);
+  }
+
+  @Override
+  protected void onDestroy() {
+    super.onDestroy();
+    delegate.onDestroy(this, this);
+  }
+
+  @Override
+  public void onMasterSecretCleared() {
+    finish();
+  }
+
+  @Override
+  public void onNewMasterSecret(MasterSecret masterSecret) {}
+
+}

src/org/thoughtcrime/securesms/PassphraseRequiredSherlockFragmentActivity.java

@@ -0,0 +1,44 @@
+package org.thoughtcrime.securesms;
+
+import android.os.Bundle;
+
+import org.thoughtcrime.securesms.crypto.MasterSecret;
+
+import com.actionbarsherlock.app.SherlockFragmentActivity;
+
+public class PassphraseRequiredSherlockFragmentActivity extends SherlockFragmentActivity implements PassphraseRequiredActivity {
+
+  private final PassphraseRequiredMixin delegate = new PassphraseRequiredMixin();
+
+  @Override
+  protected void onCreate(Bundle savedInstanceState) {
+    super.onCreate(savedInstanceState);
+    delegate.onCreate(this, this);
+  }
+
+  @Override
+  protected void onResume() {
+    super.onResume();
+    delegate.onResume(this, this);
+  }
+
+  @Override
+  protected void onPause() {
+    super.onPause();
+    delegate.onPause(this, this);
+  }
+
+  @Override
+  protected void onDestroy() {
+    super.onDestroy();
+    delegate.onDestroy(this, this);
+  }
+
+  @Override
+  public void onMasterSecretCleared() {
+    finish();
+  }
+
+  @Override
+  public void onNewMasterSecret(MasterSecret masterSecret) {}
+}

src/org/thoughtcrime/securesms/PassphraseRequiredSherlockListActivity.java

@@ -0,0 +1,45 @@
+package org.thoughtcrime.securesms;
+
+import android.os.Bundle;
+
+import org.thoughtcrime.securesms.crypto.MasterSecret;
+
+import com.actionbarsherlock.app.SherlockListActivity;
+
+public class PassphraseRequiredSherlockListActivity extends SherlockListActivity implements PassphraseRequiredActivity {
+
+  private final PassphraseRequiredMixin delegate = new PassphraseRequiredMixin();
+
+  @Override
+  protected void onCreate(Bundle savedInstanceState) {
+    super.onCreate(savedInstanceState);
+    delegate.onCreate(this, this);
+  }
+
+  @Override
+  protected void onResume() {
+    super.onResume();
+    delegate.onResume(this, this);
+  }
+
+  @Override
+  protected void onPause() {
+    super.onPause();
+    delegate.onPause(this, this);
+  }
+
+  @Override
+  protected void onDestroy() {
+    super.onDestroy();
+    delegate.onDestroy(this, this);
+  }
+
+  @Override
+  public void onMasterSecretCleared() {
+    finish();
+  }
+
+  @Override
+  public void onNewMasterSecret(MasterSecret masterSecret) {}
+
+}

src/org/thoughtcrime/securesms/PassphraseRequiredSherlockPreferenceActivity.java

@@ -0,0 +1,48 @@
+package org.thoughtcrime.securesms;
+
+import android.os.Bundle;
+
+import org.thoughtcrime.securesms.crypto.MasterSecret;
+
+import com.actionbarsherlock.app.SherlockPreferenceActivity;
+
+public abstract class PassphraseRequiredSherlockPreferenceActivity
+  extends SherlockPreferenceActivity
+  implements PassphraseRequiredActivity
+{
+
+  private final PassphraseRequiredMixin delegate = new PassphraseRequiredMixin();
+
+  @Override
+  protected void onCreate(Bundle savedInstanceState) {
+    super.onCreate(savedInstanceState);
+    delegate.onCreate(this, this);
+  }
+
+  @Override
+  protected void onResume() {
+    super.onResume();
+    delegate.onResume(this, this);
+  }
+
+  @Override
+  protected void onPause() {
+    super.onPause();
+    delegate.onPause(this, this);
+  }
+
+  @Override
+  protected void onDestroy() {
+    super.onDestroy();
+    delegate.onDestroy(this, this);
+  }
+
+  @Override
+  public void onMasterSecretCleared() {
+    finish();
+  }
+
+  @Override
+  public void onNewMasterSecret(MasterSecret masterSecret) {}
+
+}

src/org/thoughtcrime/securesms/ReceiveKeyActivity.java

@@ -16,7 +16,6 @@
  */
 package org.thoughtcrime.securesms;
 
-import android.app.Activity;
 import android.content.Intent;
 import android.os.Bundle;
 import android.util.Log;
@@ -40,7 +39,7 @@ import org.thoughtcrime.securesms.util.MemoryCleaner;
  * @author Moxie Marlinspike
  */
 
-public class ReceiveKeyActivity extends Activity {
+public class ReceiveKeyActivity extends PassphraseRequiredSherlockActivity {
 
   private TextView descriptionText;
   private TextView signatureText;
@@ -171,6 +170,7 @@ public class ReceiveKeyActivity extends Activity {
   }
 
   private class VerifyIdentityListener implements View.OnClickListener {
+    @Override
     public void onClick(View v) {
       Intent intent = new Intent(ReceiveKeyActivity.this, VerifyIdentityActivity.class);
       intent.putExtra("recipient", recipient);
@@ -181,6 +181,7 @@ public class ReceiveKeyActivity extends Activity {
   }
 
   private class VerifySessionListener implements View.OnClickListener {
+    @Override
     public void onClick(View v) {
       Intent intent = new Intent(ReceiveKeyActivity.this, VerifyKeysActivity.class);
       intent.putExtra("recipient", recipient);
@@ -191,6 +192,7 @@ public class ReceiveKeyActivity extends Activity {
   }
 
   private class OkListener implements View.OnClickListener {
+    @Override
     public void onClick(View v) {
       keyExchangeProcessor.processKeyExchangeMessage(keyExchangeMessage, threadId);
       finish();
@@ -198,6 +200,7 @@ public class ReceiveKeyActivity extends Activity {
   }
 
   private class CancelListener implements View.OnClickListener {
+    @Override
     public void onClick(View v) {
       ReceiveKeyActivity.this.finish();
     }

src/org/thoughtcrime/securesms/SaveIdentityActivity.java

@@ -25,8 +25,6 @@ import android.widget.Button;
 import android.widget.EditText;
 import android.widget.Toast;
 
-import com.actionbarsherlock.app.SherlockActivity;
-
 import org.thoughtcrime.securesms.crypto.IdentityKey;
 import org.thoughtcrime.securesms.crypto.InvalidKeyException;
 import org.thoughtcrime.securesms.crypto.MasterSecret;
@@ -39,7 +37,7 @@ import org.thoughtcrime.securesms.util.MemoryCleaner;
  *
  * @author Moxie Marlinspike
  */
-public class SaveIdentityActivity extends SherlockActivity {
+public class SaveIdentityActivity extends PassphraseRequiredSherlockActivity {
 
   private MasterSecret masterSecret;
   private IdentityKey identityKey;
@@ -83,6 +81,7 @@ public class SaveIdentityActivity extends SherlockActivity {
   }
 
   private class OkListener implements View.OnClickListener {
+    @Override
     public void onClick(View v) {
       if (identityName.getText() == null || identityName.getText().toString().trim().length() == 0) {
         Toast.makeText(SaveIdentityActivity.this,
@@ -99,6 +98,7 @@ public class SaveIdentityActivity extends SherlockActivity {
         builder.setMessage(R.string.SaveIdentityActivity_an_identity_key_with_the_specified_name_already_exists);
         builder.setPositiveButton(R.string.SaveIdentityActivity_manage_identities,
                                   new DialogInterface.OnClickListener() {
+          @Override
           public void onClick(DialogInterface dialog, int which) {
             Intent intent = new Intent(SaveIdentityActivity.this, ReviewIdentitiesActivity.class);
             intent.putExtra("master_secret", masterSecret);
@@ -115,9 +115,9 @@ public class SaveIdentityActivity extends SherlockActivity {
   }
 
   private class CancelListener implements View.OnClickListener {
+    @Override
     public void onClick(View v) {
       finish();
     }
   }
-
 }

src/org/thoughtcrime/securesms/service/KeyCachingService.java

@@ -20,6 +20,7 @@ import android.app.AlarmManager;
 import android.app.Notification;
 import android.app.PendingIntent;
 import android.app.Service;
+import android.content.Context;
 import android.content.Intent;
 import android.content.SharedPreferences;
 import android.os.Binder;
@@ -44,8 +45,7 @@ import org.thoughtcrime.securesms.notifications.MessageNotifier;
 
 public class KeyCachingService extends Service {
 
-  public static final int    NOTIFICATION_ID    = 1337;
-  public static final int    SERVICE_RUNNING_ID = 4141;
+  public static final int SERVICE_RUNNING_ID = 4141;
 
   public  static final String KEY_PERMISSION           = "org.thoughtcrime.securesms.ACCESS_SECRETS";
   public  static final String NEW_KEY_EVENT            = "org.thoughtcrime.securesms.service.action.NEW_KEY_EVENT";
@@ -215,4 +215,16 @@ public class KeyCachingService extends Service {
       return KeyCachingService.this;
     }
   }
+
+  public static void registerPassphraseActivityStarted(Context activity) {
+    Intent intent = new Intent(activity, KeyCachingService.class);
+    intent.setAction(KeyCachingService.ACTIVITY_START_EVENT);
+    activity.startService(intent);
+  }
+
+  public static void registerPassphraseActivityStopped(Context activity) {
+    Intent intent = new Intent(activity, KeyCachingService.class);
+    intent.setAction(KeyCachingService.ACTIVITY_STOP_EVENT);
+    activity.startService(intent);
+  }
 }