Merge branch 'social-backup-shard-return' into 'social-backup-poc'

Social backup shard return

See merge request briar/briar!1433

briar-android/src/main/AndroidManifest.xml

@@ -157,25 +157,7 @@
 		</activity>
 
 		<activity
-			android:name="org.briarproject.briar.android.socialbackup.recover.RecoverActivity"
+			android:name="org.briarproject.briar.android.socialbackup.recover.CustodianReturnShardActivity"
-			android:label="@string/activity_name_recovery"
-			android:parentActivityName="org.briarproject.briar.android.account.NewOrRecoverActivity">
-			<meta-data
-				android:name="android.support.PARENT_ACTIVITY"
-				android:value="org.briarproject.briar.android.account.NewOrRecoverActivity" />
-		</activity>
-
-		<activity
-			android:name="org.briarproject.briar.android.socialbackup.recover.ReturnShardActivity"
-			android:label="@string/activity_name_recovery"
-			android:parentActivityName="org.briarproject.briar.android.account.NewOrRecoverActivity">
-			<meta-data
-				android:name="android.support.PARENT_ACTIVITY"
-				android:value="org.briarproject.briar.android.account.NewOrRecoverActivity" />
-		</activity>
-
-		<activity
-			android:name="org.briarproject.briar.android.socialbackup.CustodianHelpRecoverActivity"
 			android:label="@string/activity_name_custodian_help_recovery"
 			android:parentActivityName="org.briarproject.briar.android.conversation.ConversationActivity">
 			<meta-data
@@ -183,6 +165,16 @@
 				android:value="org.briarproject.briar.android.conversation.ConversationActivity" />
 		</activity>
 
+		<activity
+			android:name="org.briarproject.briar.android.socialbackup.recover.OwnerReturnShardActivity"
+			android:label="@string/activity_name_recovery"
+			android:parentActivityName="org.briarproject.briar.android.account.NewOrRecoverActivity">
+			<meta-data
+				android:name="android.support.PARENT_ACTIVITY"
+				android:value="org.briarproject.briar.android.account.NewOrRecoverActivity" />
+		</activity>
+
+
 		<activity
 			android:name="org.briarproject.briar.android.conversation.ConversationActivity"
 			android:label="@string/app_name"

briar-android/src/main/java/org/briarproject/briar/android/AppModule.java

@@ -42,7 +42,8 @@ import org.briarproject.briar.android.privategroup.list.GroupListModule;
 import org.briarproject.briar.android.reporting.DevReportModule;
 import org.briarproject.briar.android.settings.SettingsModule;
 import org.briarproject.briar.android.sharing.SharingModule;
-import org.briarproject.briar.android.socialbackup.recover.ReturnShardModule;
+import org.briarproject.briar.android.socialbackup.recover.CustodianReturnShardModule;
+import org.briarproject.briar.android.socialbackup.recover.OwnerReturnShardModule;
 import org.briarproject.briar.android.test.TestAvatarCreatorImpl;
 import org.briarproject.briar.android.viewmodel.ViewModelModule;
 import org.briarproject.briar.api.android.AndroidNotificationManager;
@@ -92,7 +93,8 @@ import static org.briarproject.briar.android.TestingConstants.IS_DEBUG_BUILD;
 		GroupListModule.class,
 		GroupConversationModule.class,
 		SharingModule.class,
-		ReturnShardModule.class
+		OwnerReturnShardModule.class,
+		CustodianReturnShardModule.class
 })
 public class AppModule {
 

briar-android/src/main/java/org/briarproject/briar/android/account/NewOrRecoverActivity.java

@@ -7,8 +7,7 @@ import org.briarproject.briar.R;
 import org.briarproject.briar.android.activity.ActivityComponent;
 import org.briarproject.briar.android.activity.BaseActivity;
 import org.briarproject.briar.android.fragment.BaseFragment;
-import org.briarproject.briar.android.socialbackup.recover.RecoverActivity;
+import org.briarproject.briar.android.socialbackup.recover.OwnerReturnShardActivity;
-import org.briarproject.briar.android.socialbackup.recover.ReturnShardActivity;
 
 import static android.content.Intent.FLAG_ACTIVITY_CLEAR_TASK;
 import static android.content.Intent.FLAG_ACTIVITY_CLEAR_TOP;
@@ -47,7 +46,7 @@ public class NewOrRecoverActivity extends BaseActivity implements
 	@Override
 	public void recoverAccountChosen() {
 		finish();
-		Intent i = new Intent(this, ReturnShardActivity.class);
+		Intent i = new Intent(this, OwnerReturnShardActivity.class);
 		i.addFlags(FLAG_ACTIVITY_NEW_TASK | FLAG_ACTIVITY_CLEAR_TOP |
 				FLAG_ACTIVITY_CLEAR_TASK | FLAG_ACTIVITY_TASK_ON_HOME);
 		startActivity(i);

briar-android/src/main/java/org/briarproject/briar/android/activity/ActivityComponent.java

@@ -80,18 +80,20 @@ import org.briarproject.briar.android.sharing.ShareBlogFragment;
 import org.briarproject.briar.android.sharing.ShareForumActivity;
 import org.briarproject.briar.android.sharing.ShareForumFragment;
 import org.briarproject.briar.android.sharing.SharingModule;
-//import org.briarproject.briar.android.socialbackup.CustodianDisplayFragment;
+import org.briarproject.briar.android.socialbackup.recover.CustodianRecoveryModeExplainerFragment;
-import org.briarproject.briar.android.socialbackup.CustodianHelpRecoverActivity;
 import org.briarproject.briar.android.socialbackup.CustodianSelectorFragment;
 import org.briarproject.briar.android.socialbackup.DistributedBackupActivity;
 import org.briarproject.briar.android.socialbackup.ExistingBackupFragment;
+import org.briarproject.briar.android.socialbackup.recover.CustodianReturnShardActivity;
+import org.briarproject.briar.android.socialbackup.recover.CustodianReturnShardFragment;
+import org.briarproject.briar.android.socialbackup.recover.CustodianReturnShardSuccessFragment;
 import org.briarproject.briar.android.socialbackup.recover.OwnerRecoveryModeExplainerFragment;
-import org.briarproject.briar.android.socialbackup.recover.RecoverActivity;
+import org.briarproject.briar.android.socialbackup.recover.OwnerRecoveryModeMainFragment;
+import org.briarproject.briar.android.socialbackup.recover.OwnerReturnShardActivity;
+import org.briarproject.briar.android.socialbackup.recover.OwnerReturnShardFragment;
 import org.briarproject.briar.android.socialbackup.ShardsSentFragment;
 import org.briarproject.briar.android.socialbackup.ThresholdSelectorFragment;
 import org.briarproject.briar.android.socialbackup.creation.CreateBackupModule;
-import org.briarproject.briar.android.socialbackup.recover.ReturnShardActivity;
-import org.briarproject.briar.android.socialbackup.recover.ReturnShardFragment;
 import org.briarproject.briar.android.splash.SplashScreenActivity;
 import org.briarproject.briar.android.test.TestDataActivity;
 
@@ -198,9 +200,11 @@ public interface ActivityComponent {
 
 	void inject(NewOrRecoverActivity newOrRecoverActivity);
 
-	void inject(CustodianHelpRecoverActivity custodianHelpRecoverActivity);
+	void inject(CustodianReturnShardActivity custodianReturnShardActivity);
 
-	void inject(ReturnShardActivity returnShardActivity);
+    void inject(OwnerReturnShardActivity ownerReturnShardActivity);
+
+    void inject(OwnerRecoveryModeMainFragment ownerRecoveryModeMainFragment);
 
 	// Fragments
 
@@ -264,8 +268,6 @@ public interface ActivityComponent {
 
 	void inject(DistributedBackupActivity distributedBackupActivity);
 
-	void inject(RecoverActivity recoverActivity);
-
 	void inject(DatabaseComponent databaseComponent);
 
 	void inject(CustodianSelectorFragment custodianSelectorFragment);
@@ -278,5 +280,11 @@ public interface ActivityComponent {
 
 	void inject(NewOrRecoverFragment newOrRecoverFragment);
 
-	void inject(ReturnShardFragment returnShardFragment);
+	void inject(CustodianRecoveryModeExplainerFragment custodianRecoveryModeExplainerFragment);
+
+	void inject(CustodianReturnShardFragment custodianReturnShardFragment);
+
+	void inject(OwnerReturnShardFragment ownerReturnShardFragment);
+
+	void inject(CustodianReturnShardSuccessFragment custodianReturnShardSuccessFragment);
 }

briar-android/src/main/java/org/briarproject/briar/android/conversation/ConversationActivity.java

@@ -52,7 +52,7 @@ import org.briarproject.briar.android.conversation.ConversationVisitor.TextCache
 import org.briarproject.briar.android.forum.ForumActivity;
 import org.briarproject.briar.android.introduction.IntroductionActivity;
 import org.briarproject.briar.android.privategroup.conversation.GroupActivity;
-import org.briarproject.briar.android.socialbackup.CustodianHelpRecoverActivity;
+import org.briarproject.briar.android.socialbackup.recover.CustodianReturnShardActivity;
 import org.briarproject.briar.android.util.BriarSnackbarBuilder;
 import org.briarproject.briar.android.view.BriarRecyclerView;
 import org.briarproject.briar.android.view.ImagePreview;
@@ -399,7 +399,7 @@ public class ConversationActivity extends BriarActivity
 				return true;
 			case R.id.action_help_recover_account:
 				if (contactId == null) return false;
-				Intent i = new Intent(this, CustodianHelpRecoverActivity.class);
+				Intent i = new Intent(this, CustodianReturnShardActivity.class);
 				i.putExtra(CONTACT_ID, contactId.getInt());
 				startActivity(i);
 				return true;

briar-android/src/main/java/org/briarproject/briar/android/socialbackup/CustodianHelpRecoverActivity.java

@@ -1,90 +0,0 @@
-package org.briarproject.briar.android.socialbackup;
-
-import android.content.Intent;
-import android.os.Bundle;
-import android.widget.Toast;
-
-import org.briarproject.bramble.api.contact.ContactId;
-import org.briarproject.bramble.api.db.DatabaseComponent;
-import org.briarproject.bramble.api.db.DbException;
-import org.briarproject.briar.R;
-import org.briarproject.briar.android.activity.ActivityComponent;
-import org.briarproject.briar.android.activity.BriarActivity;
-import org.briarproject.briar.android.fragment.BaseFragment;
-import org.briarproject.briar.android.socialbackup.recover.ReturnShardActivity;
-import org.briarproject.briar.api.socialbackup.MessageEncoder;
-import org.briarproject.briar.api.socialbackup.ReturnShardPayload;
-import org.briarproject.briar.api.socialbackup.SocialBackupManager;
-
-import javax.inject.Inject;
-
-import static org.briarproject.briar.android.conversation.ConversationActivity.CONTACT_ID;
-
-public class CustodianHelpRecoverActivity extends BriarActivity implements
-		BaseFragment.BaseFragmentListener, CustodianScanQrButtonListener {
-	@Override
-	public void injectActivity(ActivityComponent component) {
-		component.inject(this);
-	}
-
-	public static final String RETURN_SHARD_PAYLOAD = "ReturnShardPayload";
-
-	private ContactId contactId;
-
-	@Inject
-	public SocialBackupManager socialBackupManager;
-
-//	@Inject
-//	public MessageEncoder messageEncoder;
-
-	@Inject
-	public DatabaseComponent db;
-
-	@Override
-	public void onCreate(Bundle savedInstanceState) {
-		super.onCreate(savedInstanceState);
-		setContentView(R.layout.activity_recover); // TODO change this
-
-		Intent intent = getIntent();
-		int id = intent.getIntExtra(CONTACT_ID, -1);
-		if (id == -1) throw new IllegalStateException("No ContactId");
-		contactId = new ContactId(id);
-
-		// check if we have a shard for this secret owner
-		try {
-			db.transaction(false, txn -> {
-				if (!socialBackupManager.amCustodian(txn, contactId)) {
-					throw new DbException();
-				}
-				CustodianRecoveryModeExplainerFragment fragment =
-						new CustodianRecoveryModeExplainerFragment();
-				showInitialFragment(fragment);
-			});
-		} catch (DbException e) {
-			// TODO improve this
-			Toast.makeText(this,
-					"You do not hold a backup shard from this contact",
-					Toast.LENGTH_SHORT).show();
-			finish();
-		}
-	}
-
-	@Override
-	public void scanQrButtonClicked() {
-		try {
-			db.transaction(false, txn -> {
-				byte[] returnShardPayloadBytes = socialBackupManager
-						.getReturnShardPayloadBytes(txn, contactId);
-
-				Intent i = new Intent(this, ReturnShardActivity.class);
-				i.putExtra(RETURN_SHARD_PAYLOAD, returnShardPayloadBytes);
-				startActivity(i);
-			});
-		} catch (DbException e) {
-			Toast.makeText(this,
-					"Error reading social backup from storage",
-					Toast.LENGTH_SHORT).show();
-			finish();
-		}
-	}
-}

briar-android/src/main/java/org/briarproject/briar/android/socialbackup/CustodianRecoveryModeExplainerFragment.java

@@ -1,51 +0,0 @@
-package org.briarproject.briar.android.socialbackup;
-
-import android.content.Context;
-import android.os.Bundle;
-import android.view.LayoutInflater;
-import android.view.View;
-import android.view.ViewGroup;
-import android.widget.Button;
-
-import org.briarproject.briar.android.fragment.BaseFragment;
-
-import androidx.annotation.NonNull;
-import androidx.annotation.Nullable;
-import org.briarproject.briar.R;
-
-public class CustodianRecoveryModeExplainerFragment extends BaseFragment {
-
-	protected CustodianScanQrButtonListener listener;
-
-	public static final String TAG = CustodianRecoveryModeExplainerFragment.class.getName();
-
-	@Override
-	public void onCreate(@Nullable Bundle savedInstanceState) {
-		super.onCreate(savedInstanceState);
-		requireActivity().setTitle(R.string.title_help_recover);
-	}
-
-	@Nullable
-	@Override
-	public View onCreateView(@NonNull LayoutInflater inflater, @Nullable
-			ViewGroup container, @Nullable Bundle savedInstanceState) {
-		View view = inflater.inflate(R.layout.fragment_recovery_custodian_explainer,
-				container, false);
-
-		Button button = view.findViewById(R.id.button);
-		button.setOnClickListener(e -> listener.scanQrButtonClicked());
-		return view;
-	}
-
-	@Override
-	public void onAttach(Context context) {
-		super.onAttach(context);
-		listener = (CustodianScanQrButtonListener) context;
-	}
-
-	@Override
-	public String getUniqueTag() {
-		return TAG;
-	}
-}
-

briar-android/src/main/java/org/briarproject/briar/android/socialbackup/DarkCrystalImpl.java

@@ -1,8 +1,9 @@
 package org.briarproject.briar.android.socialbackup;
+
 import org.briarproject.bramble.api.crypto.SecretKey;
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
-import org.briarproject.briar.api.socialbackup.Shard;
 import org.briarproject.briar.api.socialbackup.DarkCrystal;
+import org.briarproject.briar.api.socialbackup.Shard;
 import org.magmacollective.darkcrystal.secretsharingwrapper.SecretSharingWrapper;
 
 import java.security.GeneralSecurityException;
@@ -13,14 +14,12 @@ import java.util.Random;
 
 import javax.inject.Inject;
 
-import dagger.Provides;
-
 import static org.briarproject.briar.socialbackup.SocialBackupConstants.SECRET_ID_BYTES;
 
 @NotNullByDefault
 public class DarkCrystalImpl implements DarkCrystal {
 
-    @Inject
+	@Inject
 	DarkCrystalImpl() {
 	}
 
@@ -30,7 +29,8 @@ public class DarkCrystalImpl implements DarkCrystal {
 		Random random = new Random();
 		byte[] secretId = new byte[SECRET_ID_BYTES];
 		random.nextBytes(secretId);
-		List<byte[]> shardsBytes = SecretSharingWrapper.share(secret.getBytes(), numShards, threshold);
+		List<byte[]> shardsBytes = SecretSharingWrapper
+				.share(secret.getBytes(), numShards, threshold);
 		List<Shard> shards = new ArrayList<>(numShards);
 		for (byte[] shardBytes : shardsBytes) {
 			shards.add(new Shard(secretId, shardBytes));
@@ -44,9 +44,10 @@ public class DarkCrystalImpl implements DarkCrystal {
 		// Check each shard has the same secret Id
 		byte[] secretId = shards.get(0).getSecretId();
 		for (Shard shard : shards) {
-			if (!Arrays.equals(shard.getSecretId(), secretId)) throw new GeneralSecurityException();
+			if (!Arrays.equals(shard.getSecretId(), secretId))
+				throw new GeneralSecurityException();
 		}
-        List<byte[]> shardsBytes = new ArrayList<>(shards.size());
+		List<byte[]> shardsBytes = new ArrayList<>(shards.size());
 		for (Shard shard : shards) {
 			shardsBytes.add(shard.getShard());
 		}

briar-android/src/main/java/org/briarproject/briar/android/socialbackup/DistributedBackupActivity.java

@@ -61,7 +61,7 @@ public class DistributedBackupActivity extends BriarActivity implements
 	@Override
 	public void contactsSelected(Collection<ContactId> contacts) {
 		Toast.makeText(this,
-				String.format("selected %d contacts", contacts.size()),
+				String.format("Selected %d contacts", contacts.size()),
 				Toast.LENGTH_SHORT).show();
 		custodians = contacts;
 		ThresholdSelectorFragment fragment =

briar-android/src/main/java/org/briarproject/briar/android/socialbackup/recover/CustodianRecoveryModeExplainerFragment.java

@@ -0,0 +1,59 @@
+package org.briarproject.briar.android.socialbackup.recover;
+
+import android.os.Bundle;
+import android.view.LayoutInflater;
+import android.view.View;
+import android.view.ViewGroup;
+import android.widget.Button;
+
+import org.briarproject.briar.R;
+import org.briarproject.briar.android.activity.ActivityComponent;
+import org.briarproject.briar.android.fragment.BaseFragment;
+
+import javax.inject.Inject;
+
+import androidx.annotation.NonNull;
+import androidx.annotation.Nullable;
+import androidx.lifecycle.ViewModelProvider;
+
+public class CustodianRecoveryModeExplainerFragment extends BaseFragment {
+
+	@Inject
+	ViewModelProvider.Factory viewModelFactory;
+
+	private CustodianReturnShardViewModel viewModel;
+
+	public static final String TAG =
+			CustodianRecoveryModeExplainerFragment.class.getName();
+
+	@Override
+	public void injectFragment(ActivityComponent component) {
+		component.inject(this);
+		viewModel = new ViewModelProvider(requireActivity(), viewModelFactory)
+				.get(CustodianReturnShardViewModel.class);
+	}
+//	@Override
+//	public void onCreate(@Nullable Bundle savedInstanceState) {
+//		super.onCreate(savedInstanceState);
+//		requireActivity().setTitle(R.string.title_help_recover);
+//	}
+
+	@Nullable
+	@Override
+	public View onCreateView(@NonNull LayoutInflater inflater, @Nullable
+			ViewGroup container, @Nullable Bundle savedInstanceState) {
+		View view =
+				inflater.inflate(R.layout.fragment_recovery_custodian_explainer,
+						container, false);
+
+		Button button = view.findViewById(R.id.button);
+		button.setOnClickListener(e -> viewModel.onContinueClicked());
+		return view;
+	}
+
+	@Override
+	public String getUniqueTag() {
+		return TAG;
+	}
+}
+

briar-android/src/main/java/org/briarproject/briar/android/socialbackup/recover/CustodianReturnShardActivity.java

@@ -0,0 +1,105 @@
+package org.briarproject.briar.android.socialbackup.recover;
+
+import android.content.Intent;
+import android.os.Bundle;
+import android.widget.Toast;
+
+import org.briarproject.bramble.api.contact.ContactId;
+import org.briarproject.bramble.api.db.DbException;
+import org.briarproject.briar.R;
+import org.briarproject.briar.android.activity.ActivityComponent;
+import org.briarproject.briar.android.activity.BriarActivity;
+import org.briarproject.briar.android.fragment.BaseFragment;
+import org.briarproject.briar.api.socialbackup.recovery.CustodianTask;
+
+import java.io.IOException;
+import java.util.logging.Logger;
+
+import javax.annotation.Nullable;
+import javax.inject.Inject;
+
+import androidx.fragment.app.FragmentManager;
+import androidx.lifecycle.ViewModelProvider;
+
+import static java.util.logging.Logger.getLogger;
+import static org.briarproject.briar.android.conversation.ConversationActivity.CONTACT_ID;
+
+public class CustodianReturnShardActivity extends BriarActivity
+		implements BaseFragment.BaseFragmentListener {
+
+	private CustodianReturnShardViewModel viewModel;
+	private static final Logger LOG =
+			getLogger(CustodianReturnShardActivity.class.getName());
+
+	@Inject
+	ViewModelProvider.Factory viewModelFactory;
+
+	@Override
+	public void injectActivity(ActivityComponent component) {
+		component.inject(this);
+		viewModel = new ViewModelProvider(this, viewModelFactory)
+				.get(CustodianReturnShardViewModel.class);
+	}
+
+	@Override
+	public void onCreate(@Nullable Bundle state) {
+		super.onCreate(state);
+
+		setContentView(R.layout.activity_fragment_container);
+		if (state == null) {
+			Intent intent = getIntent();
+			int id = intent.getIntExtra(CONTACT_ID, -1);
+			if (id == -1) throw new IllegalStateException("No ContactId");
+			ContactId contactId = new ContactId(id);
+
+			try {
+				viewModel.start(contactId);
+			} catch (IOException e) {
+				// TODO improve this
+				Toast.makeText(this,
+						"It looks like you are not connected to a Wifi network",
+						Toast.LENGTH_SHORT).show();
+			} catch (DbException e) {
+				Toast.makeText(this,
+						"You do not hold a backup piece for this contact",
+						Toast.LENGTH_SHORT).show();
+				finish();
+			}
+			showInitialFragment(new CustodianRecoveryModeExplainerFragment());
+		}
+		viewModel.getShowCameraFragment().observeEvent(this, show -> {
+			if (show) showCameraFragment();
+		});
+		viewModel.getSuccessDismissed().observeEvent(this, dismissed -> {
+			if (dismissed) finish();
+		});
+		viewModel.getState()
+				.observe(this, this::onReturnShardStateChanged);
+	}
+
+	private void onReturnShardStateChanged(CustodianTask.State state) {
+        if (state instanceof CustodianTask.State.Success) {
+	        CustodianReturnShardSuccessFragment fragment = new CustodianReturnShardSuccessFragment();
+	        showNextFragment(fragment);
+        } else if (state instanceof CustodianTask.State.Failure) {
+        	// TODO error fragment here
+	        // TODO handle reason
+	        Toast.makeText(this,
+			        "Backup piece transfer failed",
+			        Toast.LENGTH_SHORT).show();
+	        finish();
+        }
+	}
+
+	private void showCameraFragment() {
+		// FIXME #824
+		FragmentManager fm = getSupportFragmentManager();
+		if (fm.findFragmentByTag(CustodianReturnShardFragment.TAG) == null) {
+			BaseFragment f = CustodianReturnShardFragment.newInstance();
+			fm.beginTransaction()
+					.replace(R.id.fragmentContainer, f, f.getUniqueTag())
+					.addToBackStack(f.getUniqueTag())
+					.commit();
+		}
+	}
+}

briar-android/src/main/java/org/briarproject/briar/android/socialbackup/recover/CustodianReturnShardFragment.java

@@ -1,6 +1,5 @@
 package org.briarproject.briar.android.socialbackup.recover;
 
-import android.graphics.Bitmap;
 import android.os.Bundle;
 import android.view.LayoutInflater;
 import android.view.View;
@@ -17,6 +16,7 @@ import org.briarproject.briar.android.contact.add.nearby.CameraException;
 import org.briarproject.briar.android.contact.add.nearby.CameraView;
 import org.briarproject.briar.android.fragment.BaseFragment;
 import org.briarproject.briar.android.view.QrCodeView;
+import org.briarproject.briar.api.socialbackup.recovery.CustodianTask;
 
 import java.util.logging.Logger;
 
@@ -38,26 +38,25 @@ import static org.briarproject.bramble.util.LogUtils.logException;
 
 @MethodsNotNullByDefault
 @ParametersNotNullByDefault
-public class ReturnShardFragment extends BaseFragment
+public class CustodianReturnShardFragment extends BaseFragment
 		implements QrCodeView.FullscreenListener {
 
-	public static final String TAG = org.briarproject.briar.android.contact.add.nearby.AddNearbyContactFragment.class.getName();
+	public static final String TAG = CustodianReturnShardFragment.class.getName();
 
 	private static final Logger LOG = Logger.getLogger(TAG);
 
 	@Inject
 	ViewModelProvider.Factory viewModelFactory;
 
-	private ReturnShardViewModel viewModel;
+	private CustodianReturnShardViewModel viewModel;
 	private CameraView cameraView;
 	private LinearLayout cameraOverlay;
 	private View statusView;
-	private QrCodeView qrCodeView;
 	private TextView status;
 
-	public static ReturnShardFragment newInstance() {
+	public static CustodianReturnShardFragment newInstance() {
 		Bundle args = new Bundle();
-		ReturnShardFragment fragment = new ReturnShardFragment();
+		CustodianReturnShardFragment fragment = new CustodianReturnShardFragment();
 		fragment.setArguments(args);
 		return fragment;
 	}
@@ -66,7 +65,7 @@ public class ReturnShardFragment extends BaseFragment
 	public void injectFragment(ActivityComponent component) {
 		component.inject(this);
 		viewModel = new ViewModelProvider(requireActivity(), viewModelFactory)
-				.get(ReturnShardViewModel.class);
+				.get(CustodianReturnShardViewModel.class);
 	}
 
 	@Nullable
@@ -85,8 +84,6 @@ public class ReturnShardFragment extends BaseFragment
 		cameraOverlay = view.findViewById(R.id.camera_overlay);
 		statusView = view.findViewById(R.id.status_container);
 		status = view.findViewById(R.id.connect_status);
-		qrCodeView = view.findViewById(R.id.qr_code_view);
-		qrCodeView.setFullscreenListener(this);
 
 		viewModel.getState().observe(getViewLifecycleOwner(),
 				this::onReturnShardStateChanged);
@@ -130,31 +127,31 @@ public class ReturnShardFragment extends BaseFragment
 	public void setFullscreen(boolean fullscreen) {
 		LinearLayout.LayoutParams statusParams, qrCodeParams;
 		if (fullscreen) {
-			// Grow the QR code view to fill its parent
 			statusParams = new LinearLayout.LayoutParams(0, 0, 0f);
-			qrCodeParams = new LinearLayout.LayoutParams(MATCH_PARENT, MATCH_PARENT, 1f);
 		} else {
-			// Shrink the QR code view to fill half its parent
 			if (cameraOverlay.getOrientation() == HORIZONTAL) {
 				statusParams = new LinearLayout.LayoutParams(0, MATCH_PARENT, 1f);
-				qrCodeParams = new LinearLayout.LayoutParams(0, MATCH_PARENT, 1f);
 			} else {
 				statusParams = new LinearLayout.LayoutParams(MATCH_PARENT, 0, 1f);
-				qrCodeParams = new LinearLayout.LayoutParams(MATCH_PARENT, 0, 1f);
 			}
 		}
 		statusView.setLayoutParams(statusParams);
-		qrCodeView.setLayoutParams(qrCodeParams);
 		cameraOverlay.invalidate();
 	}
 
 	@UiThread
-	private void onReturnShardStateChanged(@Nullable ReturnShardState state) {
+	private void onReturnShardStateChanged(@Nullable CustodianTask.State state) {
-		if (state instanceof ReturnShardState.KeyAgreementListening) {
+		LOG.info("State changed");
-			Bitmap qrCode =
+//		if (state instanceof CustodianTask.State.Connecting) {
-					((ReturnShardState.KeyAgreementListening) state).qrCode;
+//			try {
-			qrCodeView.setQrCode(qrCode);
+//				cameraView.stop();
-		} else if (state instanceof ReturnShardState.QrCodeScanned) {
+//			} catch (CameraException e) {
+//				logCameraExceptionAndFinish(e);
+//			}
+//			cameraView.setVisibility(INVISIBLE);
+//			statusView.setVisibility(VISIBLE);
+//			status.setText(R.string.connecting_to_device);
+		if (state instanceof CustodianTask.State.SendingShard) {
 			try {
 				cameraView.stop();
 			} catch (CameraException e) {
@@ -162,15 +159,13 @@ public class ReturnShardFragment extends BaseFragment
 			}
 			cameraView.setVisibility(INVISIBLE);
 			statusView.setVisibility(VISIBLE);
-			status.setText(R.string.connecting_to_device);
+			status.setText("Sending shard");
-		} else if (state instanceof ReturnShardState.KeyAgreementWaiting) {
+		} else if (state instanceof CustodianTask.State.ReceivingAck) {
-			status.setText(R.string.waiting_for_contact_to_scan);
+			status.setText("Receiving Ack");
-		} else if (state instanceof ReturnShardState.KeyAgreementStarted) {
+		} else if (state instanceof CustodianTask.State.Success) {
-			qrCodeView.setVisibility(INVISIBLE);
+			// TODO
-			status.setText(R.string.authenticating_with_device);
-		} else if (state instanceof ReturnShardState.SocialBackupExchangeStarted) {
 			status.setText(R.string.exchanging_contact_details);
-		} else if (state instanceof ReturnShardState.Failed) {
+		} else if (state instanceof CustodianTask.State.Failure) {
 			// the activity will replace this fragment with an error fragment
 			statusView.setVisibility(INVISIBLE);
 			cameraView.setVisibility(INVISIBLE);

briar-android/src/main/java/org/briarproject/briar/android/socialbackup/recover/CustodianReturnShardModule.java

@@ -0,0 +1,19 @@
+package org.briarproject.briar.android.socialbackup.recover;
+
+import org.briarproject.briar.android.viewmodel.ViewModelKey;
+
+import androidx.lifecycle.ViewModel;
+import dagger.Binds;
+import dagger.Module;
+import dagger.multibindings.IntoMap;
+
+@Module
+public abstract class CustodianReturnShardModule {
+
+	@Binds
+	@IntoMap
+	@ViewModelKey(CustodianReturnShardViewModel.class)
+	abstract ViewModel bindCustodianReturnShardViewModel(
+			CustodianReturnShardViewModel custodianReturnShardViewModel);
+
+}

briar-android/src/main/java/org/briarproject/briar/android/socialbackup/recover/CustodianReturnShardSuccessFragment.java

@@ -0,0 +1,59 @@
+package org.briarproject.briar.android.socialbackup.recover;
+
+import android.os.Bundle;
+import android.view.LayoutInflater;
+import android.view.View;
+import android.view.ViewGroup;
+import android.widget.Button;
+
+import org.briarproject.bramble.api.nullsafety.MethodsNotNullByDefault;
+import org.briarproject.bramble.api.nullsafety.ParametersNotNullByDefault;
+import org.briarproject.briar.R;
+import org.briarproject.briar.android.activity.ActivityComponent;
+import org.briarproject.briar.android.fragment.BaseFragment;
+
+import javax.inject.Inject;
+
+import androidx.annotation.NonNull;
+import androidx.annotation.Nullable;
+import androidx.lifecycle.ViewModelProvider;
+
+@MethodsNotNullByDefault
+@ParametersNotNullByDefault
+public class CustodianReturnShardSuccessFragment extends
+		BaseFragment {
+
+	public static final String TAG =
+			CustodianReturnShardFragment.class.getName();
+
+	@Inject
+	ViewModelProvider.Factory viewModelFactory;
+
+	private CustodianReturnShardViewModel viewModel;
+
+	@Override
+	public void injectFragment(ActivityComponent component) {
+		component.inject(this);
+		viewModel = new ViewModelProvider(requireActivity(), viewModelFactory)
+				.get(CustodianReturnShardViewModel.class);
+	}
+
+	@Nullable
+	@Override
+	public View onCreateView(@NonNull LayoutInflater inflater,
+			@Nullable ViewGroup container,
+			@Nullable Bundle savedInstanceState) {
+		View view = inflater.inflate(R.layout.fragment_recovery_custodian_done,
+				container, false);
+
+		Button button = view.findViewById(R.id.button);
+		button.setOnClickListener(e -> viewModel.onSuccessDismissed());
+
+		return view;
+	}
+
+	@Override
+	public String getUniqueTag() {
+		return TAG;
+	}
+}

briar-android/src/main/java/org/briarproject/briar/android/socialbackup/recover/CustodianReturnShardViewModel.java

@@ -0,0 +1,189 @@
+package org.briarproject.briar.android.socialbackup.recover;
+
+import android.app.Application;
+import android.net.wifi.WifiInfo;
+import android.net.wifi.WifiManager;
+import android.widget.Toast;
+
+import com.google.zxing.Result;
+
+import org.briarproject.bramble.api.contact.ContactId;
+import org.briarproject.bramble.api.db.DatabaseComponent;
+import org.briarproject.bramble.api.db.DbException;
+import org.briarproject.bramble.api.lifecycle.IoExecutor;
+import org.briarproject.bramble.api.system.AndroidExecutor;
+import org.briarproject.briar.R;
+import org.briarproject.briar.android.contact.add.nearby.QrCodeDecoder;
+import org.briarproject.briar.android.viewmodel.LiveEvent;
+import org.briarproject.briar.android.viewmodel.MutableLiveEvent;
+import org.briarproject.briar.api.socialbackup.SocialBackupManager;
+import org.briarproject.briar.api.socialbackup.recovery.CustodianTask;
+
+import java.io.IOException;
+import java.net.InetAddress;
+import java.net.UnknownHostException;
+import java.nio.charset.Charset;
+import java.util.concurrent.Executor;
+import java.util.logging.Logger;
+
+import javax.inject.Inject;
+
+import androidx.annotation.NonNull;
+import androidx.annotation.UiThread;
+import androidx.lifecycle.AndroidViewModel;
+import androidx.lifecycle.LiveData;
+import androidx.lifecycle.MutableLiveData;
+
+import static android.content.Context.WIFI_SERVICE;
+import static android.widget.Toast.LENGTH_LONG;
+import static java.util.logging.Level.INFO;
+import static java.util.logging.Level.WARNING;
+import static java.util.logging.Logger.getLogger;
+
+public class CustodianReturnShardViewModel extends AndroidViewModel
+		implements QrCodeDecoder.ResultCallback, CustodianTask.Observer {
+
+	private static final Logger LOG =
+			getLogger(CustodianReturnShardViewModel.class.getName());
+
+	private final AndroidExecutor androidExecutor;
+	private final Executor ioExecutor;
+	private final SocialBackupManager socialBackupManager;
+	private final DatabaseComponent db;
+	final QrCodeDecoder qrCodeDecoder;
+	private boolean wasContinueClicked = false;
+	private boolean qrCodeRead = false;
+	private WifiManager wifiManager;
+	private final MutableLiveEvent<Boolean> showCameraFragment =
+			new MutableLiveEvent<>();
+	private final MutableLiveEvent<Boolean> successDismissed =
+			new MutableLiveEvent<>();
+	private final MutableLiveData<CustodianTask.State> state =
+			new MutableLiveData<>();
+	private final CustodianTask task;
+	private byte[] returnShardPayloadBytes;
+
+	@SuppressWarnings("CharsetObjectCanBeUsed") // Requires minSdkVersion >= 19
+	private static final Charset ISO_8859_1 = Charset.forName("ISO-8859-1");
+
+	@Inject
+	public CustodianReturnShardViewModel(
+			@NonNull Application app,
+			@IoExecutor Executor ioExecutor,
+			SocialBackupManager socialBackupManager,
+			DatabaseComponent db,
+			CustodianTask task,
+			AndroidExecutor androidExecutor) {
+		super(app);
+
+		this.androidExecutor = androidExecutor;
+		this.ioExecutor = ioExecutor;
+		this.socialBackupManager = socialBackupManager;
+		this.db = db;
+		this.task = task;
+		qrCodeDecoder = new QrCodeDecoder(androidExecutor, ioExecutor, this);
+		wifiManager = (WifiManager) app.getSystemService(WIFI_SERVICE);
+	}
+
+	private InetAddress getWifiIpv4Address() {
+		if (wifiManager == null) return null;
+		// If we're connected to a wifi network, return its address
+		WifiInfo info = wifiManager.getConnectionInfo();
+		if (info != null && info.getIpAddress() != 0) {
+			return intToInetAddress(info.getIpAddress());
+		}
+		return null;
+	}
+
+	// TODO this is not the right place for this
+	private InetAddress intToInetAddress(int ip) {
+		byte[] ipBytes = new byte[4];
+		ipBytes[0] = (byte) (ip & 0xFF);
+		ipBytes[1] = (byte) ((ip >> 8) & 0xFF);
+		ipBytes[2] = (byte) ((ip >> 16) & 0xFF);
+		ipBytes[3] = (byte) ((ip >> 24) & 0xFF);
+		try {
+			return InetAddress.getByAddress(ipBytes);
+		} catch (UnknownHostException e) {
+			// Should only be thrown if address has illegal length
+			throw new AssertionError(e);
+		}
+	}
+
+	public void start(ContactId contactId) throws DbException, IOException {
+		InetAddress inetAddress = getWifiIpv4Address();
+		LOG.info("Client InetAddress: " + inetAddress);
+		if (inetAddress == null)
+			throw new IOException("Cannot get IP on local wifi");
+
+		db.transaction(false, txn -> {
+			if (!socialBackupManager.amCustodian(txn, contactId)) {
+				throw new DbException();
+			}
+			returnShardPayloadBytes = socialBackupManager
+					.getReturnShardPayloadBytes(txn, contactId);
+		});
+		task.cancel();
+		task.start(this, returnShardPayloadBytes);
+	}
+
+	@IoExecutor
+	@Override
+	public void onQrCodeDecoded(Result result) {
+		LOG.info("Got result from decoder");
+		if (qrCodeRead) return;
+		try {
+			byte[] payloadBytes = result.getText().getBytes(ISO_8859_1);
+			if (LOG.isLoggable(INFO))
+				LOG.info("Remote payload is " + payloadBytes.length + " bytes");
+			ioExecutor.execute(() -> {
+				task.qrCodeDecoded(payloadBytes);
+			});
+		} catch (IllegalArgumentException e) {
+			LOG.log(WARNING, "QR Code Invalid", e);
+			androidExecutor.runOnUiThread(() -> Toast.makeText(getApplication(),
+					R.string.qr_code_invalid, LENGTH_LONG).show());
+			ioExecutor.execute(() -> {
+				task.qrCodeDecoded(null);
+			});
+		}
+	}
+
+	@UiThread
+	public void onContinueClicked() {
+		wasContinueClicked = true;
+//		checkPermissions.setEvent(true);
+		showCameraFragment.setEvent(true);
+	}
+
+	@UiThread
+	public void onSuccessDismissed() {
+		successDismissed.setEvent(true);
+	}
+
+
+	QrCodeDecoder getQrCodeDecoder() {
+		return qrCodeDecoder;
+	}
+
+	LiveEvent<Boolean> getShowCameraFragment() {
+		return showCameraFragment;
+	}
+
+	LiveEvent<Boolean> getSuccessDismissed() {
+		return successDismissed;
+	}
+
+	LiveData<CustodianTask.State> getState() {
+		return state;
+	}
+
+	@Override
+	public void onStateChanged(CustodianTask.State state) {
+		this.state.postValue(state);
+		// Connecting, SendingShard, ReceivingAck, Success, Failure
+		if (state instanceof CustodianTask.State.SendingShard) {
+			qrCodeRead = true;
+		}
+	}
+}

briar-android/src/main/java/org/briarproject/briar/android/socialbackup/recover/OwnerRecoveryModeExplainerFragment.java

@@ -24,7 +24,7 @@ public class OwnerRecoveryModeExplainerFragment extends BaseFragment {
 	@Inject
 	ViewModelProvider.Factory viewModelFactory;
 
-	private ReturnShardViewModel viewModel;
+	private OwnerReturnShardViewModel viewModel;
 
 //	@Override
 //	public void onCreate(@Nullable Bundle savedInstanceState) {
@@ -36,7 +36,7 @@ public class OwnerRecoveryModeExplainerFragment extends BaseFragment {
 	public void injectFragment(ActivityComponent component) {
 		component.inject(this);
 		viewModel = new ViewModelProvider(requireActivity(), viewModelFactory)
-				.get(ReturnShardViewModel.class);
+				.get(OwnerReturnShardViewModel.class);
 	}
 
 	@Override
@@ -47,11 +47,10 @@ public class OwnerRecoveryModeExplainerFragment extends BaseFragment {
 	public View onCreateView(@NonNull LayoutInflater inflater,
 			@Nullable ViewGroup container,
 			@Nullable Bundle savedInstanceState) {
-		System.out.println("GOt here *************************************");
 		View view = inflater.inflate(R.layout.fragment_recovery_owner_explainer,
 				container, false);
 		Button button = view.findViewById(R.id.beginButton);
-		button.setOnClickListener(e -> viewModel.onContinueClicked());
+		button.setOnClickListener(e -> viewModel.onStartClicked());
 
 		return view;
 	}

briar-android/src/main/java/org/briarproject/briar/android/socialbackup/recover/OwnerRecoveryModeMainFragment.java

@@ -1,4 +1,4 @@
-package org.briarproject.briar.android.socialbackup;
+package org.briarproject.briar.android.socialbackup.recover;
 
 import android.content.Context;
 import android.os.Bundle;
@@ -9,44 +9,47 @@ import android.widget.Button;
 import android.widget.TextView;
 
 import org.briarproject.briar.R;
+import org.briarproject.briar.android.activity.ActivityComponent;
 import org.briarproject.briar.android.fragment.BaseFragment;
+import org.briarproject.briar.android.socialbackup.ScanQrButtonListener;
+
+import javax.inject.Inject;
 
 import androidx.annotation.NonNull;
 import androidx.annotation.Nullable;
+import androidx.lifecycle.ViewModelProvider;
 
 public class OwnerRecoveryModeMainFragment extends BaseFragment {
 
-	protected ScanQrButtonListener listener;
-
 	public static final String NUM_RECOVERED = "num_recovered";
 
 	public static final String TAG =
 			OwnerRecoveryModeMainFragment.class.getName();
 
-	public static OwnerRecoveryModeMainFragment newInstance(int numRecovered) {
+	@Inject
-		Bundle args = new Bundle();
+	ViewModelProvider.Factory viewModelFactory;
-		args.putInt(NUM_RECOVERED, numRecovered);
-		OwnerRecoveryModeMainFragment fragment =
-				new OwnerRecoveryModeMainFragment();
-		fragment.setArguments(args);
-		return fragment;
-	}
 
-	private int numShards;
+	private OwnerReturnShardViewModel viewModel;
+
+	@Override
+	public void injectFragment(ActivityComponent component) {
+		component.inject(this);
+		viewModel = new ViewModelProvider(requireActivity(), viewModelFactory)
+				.get(OwnerReturnShardViewModel.class);
+	}
 
 	@Override
 	public String getUniqueTag() {
 		return TAG;
 	}
 
-	@Override
+//	@Override
-	public void onCreate(@Nullable Bundle savedInstanceState) {
+//	public void onCreate(@Nullable Bundle savedInstanceState) {
-		super.onCreate(savedInstanceState);
+//		super.onCreate(savedInstanceState);
-		requireActivity().setTitle(R.string.title_recovery_mode);
+//		requireActivity().setTitle(R.string.title_recovery_mode);
-
+//
-		Bundle args = requireArguments();
+//		Bundle args = requireArguments();
-		numShards = args.getInt(NUM_RECOVERED);
+//	}
-	}
 
 	@Nullable
 	@Override
@@ -57,17 +60,10 @@ public class OwnerRecoveryModeMainFragment extends BaseFragment {
 				container, false);
 
 		TextView textViewCount = view.findViewById(R.id.textViewShardCount);
-		textViewCount.setText(String.format("%d", numShards));
+		textViewCount.setText(String.format("%d", viewModel.getNumberOfShards()));
 
 		Button button = view.findViewById(R.id.button);
-		button.setOnClickListener(e -> listener.scanQrButtonClicked());
+		button.setOnClickListener(e -> viewModel.onContinueClicked());
 		return view;
 	}
-
-	@Override
-	public void onAttach(Context context) {
-		super.onAttach(context);
-		listener = (ScanQrButtonListener) context;
-	}
-
 }

briar-android/src/main/java/org/briarproject/briar/android/socialbackup/recover/OwnerReturnShardActivity.java

@@ -0,0 +1,177 @@
+package org.briarproject.briar.android.socialbackup.recover;
+
+import android.content.Intent;
+import android.os.Bundle;
+import android.view.MenuItem;
+import android.widget.Toast;
+
+import org.briarproject.bramble.api.FormatException;
+import org.briarproject.bramble.api.nullsafety.MethodsNotNullByDefault;
+import org.briarproject.bramble.api.nullsafety.ParametersNotNullByDefault;
+import org.briarproject.briar.R;
+import org.briarproject.briar.android.activity.ActivityComponent;
+import org.briarproject.briar.android.activity.BaseActivity;
+import org.briarproject.briar.android.fragment.BaseFragment;
+import org.briarproject.briar.api.socialbackup.ReturnShardPayload;
+import org.briarproject.briar.api.socialbackup.recovery.SecretOwnerTask;
+
+import java.security.GeneralSecurityException;
+import java.util.logging.Logger;
+
+import javax.annotation.Nullable;
+import javax.inject.Inject;
+
+import androidx.fragment.app.FragmentManager;
+import androidx.lifecycle.ViewModelProvider;
+
+import static android.content.Intent.FLAG_ACTIVITY_CLEAR_TOP;
+import static java.util.logging.Logger.getLogger;
+
+@MethodsNotNullByDefault
+@ParametersNotNullByDefault
+public class OwnerReturnShardActivity extends BaseActivity
+		implements BaseFragment.BaseFragmentListener {
+
+	private static final Logger LOG =
+			getLogger(OwnerReturnShardActivity.class.getName());
+
+	@Inject
+	ViewModelProvider.Factory viewModelFactory;
+
+	private OwnerReturnShardViewModel viewModel;
+
+//	private final ActivityResultLauncher<String[]> permissionLauncher =
+//			registerForActivityResult(
+//					new ActivityResultContracts.RequestMultiplePermissions(),
+//					r ->
+//							permissionManager.onRequestPermissionResult(r,
+//									viewModel::showQrCodeFragmentIfAllowed));
+
+	@Override
+	public void injectActivity(ActivityComponent component) {
+		component.inject(this);
+		viewModel = new ViewModelProvider(this, viewModelFactory)
+				.get(OwnerReturnShardViewModel.class);
+	}
+
+	@Override
+	public void onCreate(@Nullable Bundle state) {
+		super.onCreate(state);
+
+		setContentView(R.layout.activity_fragment_container);
+		if (state == null) {
+			showInitialFragment(new OwnerRecoveryModeExplainerFragment());
+		}
+		viewModel.getShowQrCodeFragment().observeEvent(this, show -> {
+			if (show) {
+				viewModel.startListening();
+				showQrCodeFragment();
+			}
+		});
+		viewModel.getStartClicked().observeEvent(this, start -> {
+			if (start) {
+				showNextFragment(new OwnerRecoveryModeMainFragment());
+			}
+		});
+		viewModel.getState()
+				.observe(this, this::onReturnShardStateChanged);
+	}
+
+	@Override
+	public void onStart() {
+		super.onStart();
+	}
+
+	@Override
+	protected void onPostResume() {
+		super.onPostResume();
+//		viewModel.setIsActivityResumed(true);
+	}
+
+	@Override
+	protected void onPause() {
+		super.onPause();
+//		viewModel.setIsActivityResumed(false);
+	}
+
+	@Override
+	public boolean onOptionsItemSelected(MenuItem item) {
+		if (item.getItemId() == android.R.id.home) {
+			onBackPressed();
+			return true;
+		}
+		return super.onOptionsItemSelected(item);
+	}
+
+	@Override
+	public void onBackPressed() {
+		// TODO should we cancel the return shard task here?
+		super.onBackPressed();
+	}
+
+	private void showQrCodeFragment() {
+		LOG.info("showQrCodeFragment called");
+		FragmentManager fm = getSupportFragmentManager();
+		if (fm.findFragmentByTag(OwnerReturnShardFragment.TAG) == null) {
+			BaseFragment f = OwnerReturnShardFragment.newInstance();
+			fm.beginTransaction()
+					.replace(R.id.fragmentContainer, f, f.getUniqueTag())
+					.addToBackStack(f.getUniqueTag())
+					.commit();
+		}
+	}
+
+
+	private void onReturnShardStateChanged(SecretOwnerTask.State state) {
+		if (state instanceof SecretOwnerTask.State.Success) {
+			ReturnShardPayload shardPayload = ((SecretOwnerTask.State.Success) state).getRemotePayload();
+			boolean added = viewModel.addToShardSet(shardPayload);
+			Toast.makeText(this,
+					"Success - got shard" + (added ? "" : " duplicate"),
+					Toast.LENGTH_SHORT).show();
+			if (added && viewModel.canRecover()) {
+				LOG.info("Secret key recovered");
+				int version = 0;
+				try {
+					version = viewModel.recover();
+				} catch (GeneralSecurityException e) {
+					LOG.warning("Unable to decrypt backup" + e.toString());
+					Toast.makeText(this,
+							"Unable to decrypt backup",
+							Toast.LENGTH_LONG).show();
+					return;
+				} catch (FormatException e) {
+					LOG.warning("Unable to parse backup" + e.getMessage() + e.getStackTrace().toString());
+					Toast.makeText(this,
+							"Unable to parse backup",
+							Toast.LENGTH_LONG).show();
+					return;
+				}
+				Toast.makeText(this,
+						"Account recovered! " + version,
+						Toast.LENGTH_LONG).show();
+				finish();
+				return;
+			}
+			onBackPressed();
+		} else if (state instanceof SecretOwnerTask.State.Failure) {
+			// TODO error screen, handle reason
+			Toast.makeText(this,
+					"Shard return failed!",
+					Toast.LENGTH_SHORT).show();
+			onBackPressed();
+//			showNextFragment(new OwnerRecoveryModeExplainerFragment());
+		}
+	}
+
+//	private void showErrorFragment() {
+//		// TODO change this for an appropriate error message fragment
+//		showNextFragment(new AddNearbyContactErrorFragment());
+//	}
+
+	@Override
+	@Deprecated
+	public void runOnDbThread(Runnable runnable) {
+		throw new RuntimeException("Don't use this deprecated method here.");
+	}
+}

briar-android/src/main/java/org/briarproject/briar/android/socialbackup/recover/OwnerReturnShardFragment.java

@@ -0,0 +1,162 @@
+package org.briarproject.briar.android.socialbackup.recover;
+
+import android.graphics.Bitmap;
+import android.os.Bundle;
+import android.view.LayoutInflater;
+import android.view.View;
+import android.view.ViewGroup;
+import android.widget.LinearLayout;
+import android.widget.TextView;
+
+import org.briarproject.bramble.api.nullsafety.MethodsNotNullByDefault;
+import org.briarproject.bramble.api.nullsafety.ParametersNotNullByDefault;
+import org.briarproject.briar.R;
+import org.briarproject.briar.android.activity.ActivityComponent;
+import org.briarproject.briar.android.fragment.BaseFragment;
+import org.briarproject.briar.android.view.QrCodeView;
+import org.briarproject.briar.api.socialbackup.recovery.SecretOwnerTask;
+
+import java.util.logging.Logger;
+
+import javax.annotation.Nullable;
+import javax.inject.Inject;
+
+import androidx.annotation.UiThread;
+import androidx.lifecycle.ViewModelProvider;
+
+import static android.content.pm.ActivityInfo.SCREEN_ORIENTATION_NOSENSOR;
+import static android.content.pm.ActivityInfo.SCREEN_ORIENTATION_UNSPECIFIED;
+import static android.view.View.INVISIBLE;
+import static android.view.View.VISIBLE;
+import static android.view.ViewGroup.LayoutParams.MATCH_PARENT;
+import static android.widget.LinearLayout.HORIZONTAL;
+
+@MethodsNotNullByDefault
+@ParametersNotNullByDefault
+public class OwnerReturnShardFragment extends BaseFragment
+		implements QrCodeView.FullscreenListener {
+
+	public static final String TAG = OwnerReturnShardFragment.class.getName();
+
+	private static final Logger LOG = Logger.getLogger(TAG);
+
+	@Inject
+	ViewModelProvider.Factory viewModelFactory;
+
+	private OwnerReturnShardViewModel viewModel;
+	private LinearLayout cameraOverlay;
+	private View statusView;
+	private QrCodeView qrCodeView;
+	private TextView status;
+
+	public static OwnerReturnShardFragment newInstance() {
+		Bundle args = new Bundle();
+		OwnerReturnShardFragment fragment = new OwnerReturnShardFragment();
+		fragment.setArguments(args);
+		return fragment;
+	}
+
+	@Override
+	public void injectFragment(ActivityComponent component) {
+		component.inject(this);
+		viewModel = new ViewModelProvider(requireActivity(), viewModelFactory)
+				.get(OwnerReturnShardViewModel.class);
+	}
+
+	@Nullable
+	@Override
+	public View onCreateView(LayoutInflater inflater,
+			@Nullable ViewGroup container,
+			@Nullable Bundle savedInstanceState) {
+		return inflater.inflate(R.layout.fragment_keyagreement_qr, container,
+				false);
+	}
+
+	@Override
+	public void onViewCreated(View view, @Nullable Bundle savedInstanceState) {
+		super.onViewCreated(view, savedInstanceState);
+		cameraOverlay = view.findViewById(R.id.camera_overlay);
+		statusView = view.findViewById(R.id.status_container);
+		status = view.findViewById(R.id.connect_status);
+		qrCodeView = view.findViewById(R.id.qr_code_view);
+		qrCodeView.setFullscreenListener(this);
+
+		viewModel.getState().observe(getViewLifecycleOwner(),
+				this::onReturnShardStateChanged);
+		Bitmap qrCodeBitmap = viewModel.getQrCodeBitmap();
+		if (qrCodeBitmap != null) {
+			qrCodeView.setQrCode(qrCodeBitmap);
+		}
+	}
+
+	@Override
+	public void onActivityCreated(@Nullable Bundle savedInstanceState) {
+		super.onActivityCreated(savedInstanceState);
+		requireActivity().setRequestedOrientation(SCREEN_ORIENTATION_NOSENSOR);
+	}
+
+	@Override
+	public void onDestroy() {
+		requireActivity()
+				.setRequestedOrientation(SCREEN_ORIENTATION_UNSPECIFIED);
+		super.onDestroy();
+	}
+
+	@Override
+	public void setFullscreen(boolean fullscreen) {
+		LinearLayout.LayoutParams statusParams, qrCodeParams;
+		if (fullscreen) {
+			// Grow the QR code view to fill its parent
+			statusParams = new LinearLayout.LayoutParams(0, 0, 0f);
+			qrCodeParams =
+					new LinearLayout.LayoutParams(MATCH_PARENT, MATCH_PARENT,
+							1f);
+		} else {
+			// Shrink the QR code view to fill half its parent
+			if (cameraOverlay.getOrientation() == HORIZONTAL) {
+				statusParams =
+						new LinearLayout.LayoutParams(0, MATCH_PARENT, 1f);
+				qrCodeParams =
+						new LinearLayout.LayoutParams(0, MATCH_PARENT, 1f);
+			} else {
+				statusParams =
+						new LinearLayout.LayoutParams(MATCH_PARENT, 0, 1f);
+				qrCodeParams =
+						new LinearLayout.LayoutParams(MATCH_PARENT, 0, 1f);
+			}
+		}
+		statusView.setLayoutParams(statusParams);
+		qrCodeView.setLayoutParams(qrCodeParams);
+		cameraOverlay.invalidate();
+	}
+
+	@UiThread
+	private void onReturnShardStateChanged(
+			@Nullable SecretOwnerTask.State state) {
+		if (state instanceof SecretOwnerTask.State.Listening) {
+			Bitmap qrCode = viewModel.getQrCodeBitmap();
+			qrCodeView.setQrCode(qrCode);
+		} else if (state instanceof SecretOwnerTask.State.ReceivingShard) {
+			statusView.setVisibility(VISIBLE);
+			status.setText(R.string.connecting_to_device);
+		} else if (state instanceof SecretOwnerTask.State.SendingAck) {
+			status.setText(R.string.waiting_for_contact_to_scan);
+		} else if (state instanceof SecretOwnerTask.State.Success) {
+			status.setText("Success");
+		} else if (state instanceof SecretOwnerTask.State.Failure) {
+			// the activity will replace this fragment with an error fragment
+			statusView.setVisibility(INVISIBLE);
+		}
+	}
+
+	@Override
+	public String getUniqueTag() {
+		return TAG;
+	}
+
+	@Override
+	protected void finish() {
+		requireActivity().getSupportFragmentManager().popBackStack();
+	}
+
+}

briar-android/src/main/java/org/briarproject/briar/android/socialbackup/recover/OwnerReturnShardModule.java

@@ -9,12 +9,12 @@ import dagger.multibindings.IntoMap;
 
 
 @Module
-public abstract class ReturnShardModule {
+public abstract class OwnerReturnShardModule {
 
 	@Binds
 	@IntoMap
-	@ViewModelKey(ReturnShardViewModel.class)
+	@ViewModelKey(OwnerReturnShardViewModel.class)
-	abstract ViewModel bindContactExchangeViewModel(
+	abstract ViewModel bindOwnerReturnShardViewModel(
-			ReturnShardViewModel returnShardViewModel);
+			OwnerReturnShardViewModel ownerReturnShardViewModel);
 
 }

briar-android/src/main/java/org/briarproject/briar/android/socialbackup/recover/OwnerReturnShardViewModel.java

@@ -0,0 +1,264 @@
+package org.briarproject.briar.android.socialbackup.recover;
+
+import android.app.Application;
+import android.graphics.Bitmap;
+import android.net.wifi.WifiInfo;
+import android.net.wifi.WifiManager;
+import android.util.DisplayMetrics;
+
+import org.briarproject.bramble.api.FormatException;
+import org.briarproject.bramble.api.crypto.SecretKey;
+import org.briarproject.bramble.api.lifecycle.IoExecutor;
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+import org.briarproject.bramble.api.system.AndroidExecutor;
+import org.briarproject.briar.android.contact.add.nearby.QrCodeUtils;
+import org.briarproject.briar.android.viewmodel.LiveEvent;
+import org.briarproject.briar.android.viewmodel.MutableLiveEvent;
+import org.briarproject.briar.api.socialbackup.BackupPayload;
+import org.briarproject.briar.api.socialbackup.DarkCrystal;
+import org.briarproject.briar.api.socialbackup.ReturnShardPayload;
+import org.briarproject.briar.api.socialbackup.Shard;
+import org.briarproject.briar.api.socialbackup.recovery.SecretOwnerTask;
+import org.briarproject.briar.socialbackup.BackupPayloadDecoder;
+import org.briarproject.briar.socialbackup.SocialBackup;
+
+import java.net.InetAddress;
+import java.net.UnknownHostException;
+import java.nio.charset.Charset;
+import java.security.GeneralSecurityException;
+import java.util.ArrayList;
+import java.util.concurrent.Executor;
+import java.util.logging.Logger;
+
+import javax.inject.Inject;
+
+import androidx.annotation.UiThread;
+import androidx.lifecycle.AndroidViewModel;
+import androidx.lifecycle.LiveData;
+import androidx.lifecycle.MutableLiveData;
+
+import static android.content.Context.WIFI_SERVICE;
+import static java.util.logging.Level.INFO;
+import static java.util.logging.Logger.getLogger;
+
+@NotNullByDefault
+class OwnerReturnShardViewModel extends AndroidViewModel
+		implements SecretOwnerTask.Observer {
+
+	private static final Logger LOG =
+			getLogger(OwnerReturnShardViewModel.class.getName());
+
+	@SuppressWarnings("CharsetObjectCanBeUsed") // Requires minSdkVersion >= 19
+	private static final Charset ISO_8859_1 = Charset.forName("ISO-8859-1");
+
+//	private ReturnShardPayload returnShardPayload;
+
+	private final AndroidExecutor androidExecutor;
+	private final Executor ioExecutor;
+	private final SecretOwnerTask task;
+	private final DarkCrystal darkCrystal;
+	private final BackupPayloadDecoder backupPayloadDecoder;
+
+	private final MutableLiveEvent<Boolean> showQrCodeFragment =
+			new MutableLiveEvent<>();
+	private final MutableLiveData<SecretOwnerTask.State> state =
+			new MutableLiveData<>();
+	private final MutableLiveEvent<Boolean> startClicked =
+			new MutableLiveEvent<>();
+	private boolean wasContinueClicked = false;
+	private boolean isActivityResumed = false;
+	private ArrayList<ReturnShardPayload> recoveredShards = new ArrayList<>();
+	private Bitmap qrCodeBitmap;
+	private WifiManager wifiManager;
+	private SecretKey secretKey;
+
+	@Inject
+	OwnerReturnShardViewModel(Application app,
+			AndroidExecutor androidExecutor,
+			SecretOwnerTask task,
+			DarkCrystal darkCrystal,
+			BackupPayloadDecoder backupPayloadDecoder,
+			@IoExecutor Executor ioExecutor) {
+		super(app);
+		this.androidExecutor = androidExecutor;
+		this.ioExecutor = ioExecutor;
+		this.backupPayloadDecoder = backupPayloadDecoder;
+		this.darkCrystal = darkCrystal;
+		this.task = task;
+		wifiManager = (WifiManager) app.getSystemService(WIFI_SERVICE);
+
+//		IntentFilter filter = new IntentFilter(ACTION_SCAN_MODE_CHANGED);
+	}
+
+	private InetAddress getWifiIpv4Address() {
+		if (wifiManager == null) return null;
+		// If we're connected to a wifi network, return its address
+		WifiInfo info = wifiManager.getConnectionInfo();
+		if (info != null && info.getIpAddress() != 0) {
+			return intToInetAddress(info.getIpAddress());
+		}
+		return null;
+	}
+
+	// TODO this is not the right place for this
+	private InetAddress intToInetAddress(int ip) {
+		byte[] ipBytes = new byte[4];
+		ipBytes[0] = (byte) (ip & 0xFF);
+		ipBytes[1] = (byte) ((ip >> 8) & 0xFF);
+		ipBytes[2] = (byte) ((ip >> 16) & 0xFF);
+		ipBytes[3] = (byte) ((ip >> 24) & 0xFF);
+		try {
+			return InetAddress.getByAddress(ipBytes);
+		} catch (UnknownHostException e) {
+			// Should only be thrown if address has illegal length
+			throw new AssertionError(e);
+		}
+	}
+
+	@Override
+	protected void onCleared() {
+		super.onCleared();
+		stopListening();
+	}
+
+	@UiThread
+	void onStartClicked() {
+       startClicked.setEvent(true);
+	}
+
+	@UiThread
+	void onContinueClicked() {
+		wasContinueClicked = true;
+		startShardReturn();
+	}
+
+	@UiThread
+	void startShardReturn() {
+		// If we return to the intro fragment, the continue button needs to be
+		// clicked again before showing the QR code fragment
+		wasContinueClicked = false;
+		// If we return to the intro fragment, we may need to enable wifi and
+//		hasEnabledWifi = false;
+		showQrCodeFragment.setEvent(true);
+	}
+
+	@UiThread
+	public void startListening() {
+		ioExecutor.execute(() -> {
+			task.start(this, getWifiIpv4Address());
+		});
+//		KeyAgreementTask oldTask = task;
+//		KeyAgreementTask newTask = keyAgreementTaskProvider.get();
+//		task = newTask;
+//		ioExecutor.execute(() -> {
+//			if (oldTask != null) oldTask.stopListening();
+//			newTask.listen();
+//		});
+	}
+
+	@UiThread
+	private void stopListening() {
+		ioExecutor.execute(() -> {
+			task.cancel();
+		});
+	}
+
+
+	/**
+	 * Set to true in onPostResume() and false in onPause(). This prevents the
+	 * QR code fragment from being shown if onRequestPermissionsResult() is
+	 * called while the activity is paused, which could cause a crash due to
+	 * https://issuetracker.google.com/issues/37067655.
+	 * TODO check if this is still happening with new permission requesting
+	 */
+	void setIsActivityResumed(boolean resumed) {
+		isActivityResumed = resumed;
+		// Workaround for
+		// https://code.google.com/p/android/issues/detail?id=190966
+//		showQrCodeFragmentIfAllowed();
+	}
+
+	LiveEvent<Boolean> getShowQrCodeFragment() {
+		return showQrCodeFragment;
+	}
+
+	LiveEvent<Boolean> getStartClicked() {
+		return startClicked;
+	}
+
+	LiveData<SecretOwnerTask.State> getState() {
+		return state;
+	}
+
+	public Bitmap getQrCodeBitmap() {
+		LOG.info("getting qrCodeBitmap");
+		return qrCodeBitmap;
+	}
+
+	public int getNumberOfShards() {
+		return recoveredShards.size();
+	}
+
+	@Override
+	public void onStateChanged(SecretOwnerTask.State state) {
+		if (state instanceof SecretOwnerTask.State.Listening) {
+			DisplayMetrics dm =
+					getApplication().getResources().getDisplayMetrics();
+			ioExecutor.execute(() -> {
+				byte[] payloadBytes = ((SecretOwnerTask.State.Listening) state)
+						.getLocalPayload();
+				if (LOG.isLoggable(INFO)) {
+					LOG.info("Local QR code payload is " + payloadBytes.length
+							+ " bytes");
+				}
+				// Use ISO 8859-1 to encode bytes directly as a string
+				String content = new String(payloadBytes, ISO_8859_1);
+				qrCodeBitmap = QrCodeUtils.createQrCode(dm, content);
+				this.state.postValue(state);
+			});
+		} else if (state instanceof SecretOwnerTask.State.Success) {
+//			startClicked.setEvent(true);
+			this.state.postValue(state);
+			// TODO do same for failure
+		}  else {
+			this.state.postValue(state);
+		}
+	}
+
+	// TODO figure out how to actually use a set for these objects
+	public boolean addToShardSet(ReturnShardPayload toAdd) {
+		boolean found = false;
+		for (ReturnShardPayload returnShardPayload : recoveredShards) {
+			if (toAdd.equals(returnShardPayload)) {
+				found = true;
+				break;
+			}
+		}
+		if (!found) recoveredShards.add(toAdd);
+		return !found;
+	}
+
+	public boolean canRecover() {
+        ArrayList<Shard> shards = new ArrayList();
+		for (ReturnShardPayload returnShardPayload : recoveredShards) {
+			// TODO check shards all have same secret id
+		   shards.add(returnShardPayload.getShard());
+		}
+		try {
+			secretKey = darkCrystal.combineShards(shards);
+		} catch (GeneralSecurityException e) {
+			// TODO handle error message
+			return false;
+		}
+		return true;
+	}
+
+	public int recover() throws FormatException, GeneralSecurityException {
+		if (secretKey == null) throw new GeneralSecurityException();
+		// TODO find backup with highest version number
+		BackupPayload backupPayload = recoveredShards.get(0).getBackupPayload();
+		SocialBackup decodedBackup = backupPayloadDecoder.decodeBackupPayload(secretKey, backupPayload);
+		int version = decodedBackup.getVersion();
+		return version;
+	}
+}

briar-android/src/main/java/org/briarproject/briar/android/socialbackup/recover/RecoverActivity.java

@@ -1,65 +0,0 @@
-package org.briarproject.briar.android.socialbackup.recover;
-
-import android.os.Bundle;
-import android.widget.Toast;
-
-import org.briarproject.briar.R;
-import org.briarproject.briar.android.activity.ActivityComponent;
-import org.briarproject.briar.android.activity.BaseActivity;
-import org.briarproject.briar.android.fragment.BaseFragment;
-import org.briarproject.briar.android.socialbackup.ExplainerDismissedListener;
-import org.briarproject.briar.android.socialbackup.OwnerRecoveryModeMainFragment;
-import org.briarproject.briar.android.socialbackup.ScanQrButtonListener;
-
-public class RecoverActivity extends BaseActivity implements
-		BaseFragment.BaseFragmentListener, ExplainerDismissedListener,
-		ScanQrButtonListener {
-
-	private int numRecovered;
-
-	@Override
-	public void onCreate(Bundle savedInstanceState) {
-		super.onCreate(savedInstanceState);
-		setContentView(R.layout.activity_recover);
-
-		numRecovered = 0; // TODO - retrieve this from somewhere
-
-		// only show the explainer if we have no shards
-		if (numRecovered == 0) {
-			OwnerRecoveryModeExplainerFragment fragment =
-					new OwnerRecoveryModeExplainerFragment();
-			showInitialFragment(fragment);
-		} else {
-			OwnerRecoveryModeMainFragment fragment =
-					OwnerRecoveryModeMainFragment.newInstance(numRecovered);
-			showInitialFragment(fragment);
-		}
-	}
-
-	@Override
-	public void injectActivity(ActivityComponent component) {
-		component.inject(this);
-	}
-
-	@Override
-	public void explainerDismissed() {
-		OwnerRecoveryModeMainFragment fragment =
-				OwnerRecoveryModeMainFragment.newInstance(numRecovered);
-		showNextFragment(fragment);
-	}
-
-	@Override
-	public void scanQrButtonClicked() {
-		// TODO
-		Toast.makeText(this,
-				"coming soon...",
-				Toast.LENGTH_SHORT).show();
-		finish();
-	}
-
-	@Override
-	@Deprecated
-	public void runOnDbThread(Runnable runnable) {
-		throw new RuntimeException("Don't use this deprecated method here.");
-	}
-}

briar-android/src/main/java/org/briarproject/briar/android/socialbackup/recover/ReturnShardActivity.java

@@ -1,266 +0,0 @@
-package org.briarproject.briar.android.socialbackup.recover;
-
-import android.content.Intent;
-import android.os.Bundle;
-import android.view.MenuItem;
-import android.widget.Toast;
-
-import org.briarproject.bramble.api.FormatException;
-import org.briarproject.bramble.api.client.ClientHelper;
-import org.briarproject.bramble.api.data.BdfList;
-import org.briarproject.bramble.api.nullsafety.MethodsNotNullByDefault;
-import org.briarproject.bramble.api.nullsafety.ParametersNotNullByDefault;
-import org.briarproject.briar.R;
-import org.briarproject.briar.android.activity.ActivityComponent;
-import org.briarproject.briar.android.activity.BaseActivity;
-import org.briarproject.briar.android.contact.add.nearby.AddNearbyContactErrorFragment;
-import org.briarproject.briar.android.contact.add.nearby.AddNearbyContactPermissionManager;
-import org.briarproject.briar.android.fragment.BaseFragment;
-import org.briarproject.briar.android.util.RequestBluetoothDiscoverable;
-import org.briarproject.briar.api.socialbackup.BackupPayload;
-import org.briarproject.briar.api.socialbackup.ReturnShardPayload;
-import org.briarproject.briar.api.socialbackup.Shard;
-
-import java.util.logging.Logger;
-
-import javax.annotation.Nullable;
-import javax.inject.Inject;
-
-import androidx.activity.result.ActivityResultLauncher;
-import androidx.activity.result.contract.ActivityResultContracts;
-import androidx.fragment.app.FragmentManager;
-import androidx.lifecycle.ViewModelProvider;
-
-import static android.bluetooth.BluetoothAdapter.ACTION_REQUEST_DISCOVERABLE;
-import static android.content.Intent.FLAG_ACTIVITY_CLEAR_TOP;
-import static android.widget.Toast.LENGTH_LONG;
-import static java.util.logging.Logger.getLogger;
-import static org.briarproject.bramble.util.ValidationUtils.checkSize;
-import static org.briarproject.briar.android.socialbackup.CustodianHelpRecoverActivity.RETURN_SHARD_PAYLOAD;
-
-@MethodsNotNullByDefault
-@ParametersNotNullByDefault
-public class ReturnShardActivity extends BaseActivity
-		implements BaseFragment.BaseFragmentListener {
-
-	private static final Logger LOG =
-			getLogger(ReturnShardActivity.class.getName());
-
-	@Inject
-	ViewModelProvider.Factory viewModelFactory;
-
-//	@Inject
-//	MessageParser messageParser;
-
-	@Inject
-	public ClientHelper clientHelper;
-
-	private ReturnShardViewModel viewModel;
-	private AddNearbyContactPermissionManager permissionManager;
-
-	private final ActivityResultLauncher<String[]> permissionLauncher =
-			registerForActivityResult(
-					new ActivityResultContracts.RequestMultiplePermissions(),
-					r ->
-							permissionManager.onRequestPermissionResult(r,
-									viewModel::showQrCodeFragmentIfAllowed));
-	private final ActivityResultLauncher<Integer> bluetoothLauncher =
-			registerForActivityResult(new RequestBluetoothDiscoverable(),
-					this::onBluetoothDiscoverableResult);
-
-	@Override
-	public void injectActivity(ActivityComponent component) {
-		component.inject(this);
-		viewModel = new ViewModelProvider(this, viewModelFactory)
-				.get(ReturnShardViewModel.class);
-		permissionManager = new AddNearbyContactPermissionManager(this,
-				permissionLauncher::launch, viewModel.isBluetoothSupported());
-	}
-
-	// TODO the following two methods should be injected from messageParser
-	private Shard parseShardMessage(BdfList body) throws FormatException {
-		// Message type, secret ID, shard
-		byte[] secretId = body.getRaw(1);
-		byte[] shard = body.getRaw(2);
-		return new Shard(secretId, shard);
-	}
-
-	private ReturnShardPayload parseReturnShardPayload(BdfList body)
-			throws FormatException {
-		checkSize(body, 2);
-		Shard shard = parseShardMessage(body.getList(0));
-		org.briarproject.briar.api.socialbackup.BackupPayload backupPayload =
-				new BackupPayload(body.getRaw(1));
-		return new ReturnShardPayload(shard, backupPayload);
-	}
-
-	@Override
-	public void onCreate(@Nullable Bundle state) {
-		super.onCreate(state);
-
-		byte[] returnShardPayloadBytes =
-				getIntent().getByteArrayExtra(RETURN_SHARD_PAYLOAD);
-		if (returnShardPayloadBytes != null) {
-			try {
-				ReturnShardPayload returnShardPayload = parseReturnShardPayload(
-						clientHelper.toList(returnShardPayloadBytes));
-				viewModel.setSending(true);
-				viewModel.setReturnShardPayload(returnShardPayload);
-			} catch (FormatException e) {
-				Toast.makeText(this,
-						"Error reading social backup",
-						Toast.LENGTH_SHORT).show();
-				finish();
-			}
-		}
-		setContentView(R.layout.activity_fragment_container);
-		if (state == null) {
-			showInitialFragment(getExplainerFragment());
-		}
-		viewModel.getCheckPermissions().observeEvent(this, check ->
-				permissionManager.checkPermissions());
-		viewModel.getRequestBluetoothDiscoverable().observeEvent(this, r ->
-				requestBluetoothDiscoverable()); // never false
-		viewModel.getShowQrCodeFragment().observeEvent(this, show -> {
-			if (show) showQrCodeFragment();
-		});
-		viewModel.getState()
-				.observe(this, this::onReturnShardStateChanged);
-	}
-
-	public BaseFragment getExplainerFragment() {
-		return new OwnerRecoveryModeExplainerFragment();
-	}
-
-	@Override
-	public void onStart() {
-		super.onStart();
-		// Permissions may have been granted manually while we were stopped
-		permissionManager.resetPermissions();
-	}
-
-	@Override
-	protected void onPostResume() {
-		super.onPostResume();
-		viewModel.setIsActivityResumed(true);
-	}
-
-	@Override
-	protected void onPause() {
-		super.onPause();
-		viewModel.setIsActivityResumed(false);
-	}
-
-	private void onBluetoothDiscoverableResult(boolean discoverable) {
-		if (discoverable) {
-			LOG.info("Bluetooth discoverability was accepted");
-			viewModel.setBluetoothDecision(
-					ReturnShardViewModel.BluetoothDecision.ACCEPTED);
-		} else {
-			LOG.info("Bluetooth discoverability was refused");
-			viewModel.setBluetoothDecision(
-					ReturnShardViewModel.BluetoothDecision.REFUSED);
-		}
-	}
-
-	@Override
-	public boolean onOptionsItemSelected(MenuItem item) {
-		if (item.getItemId() == android.R.id.home) {
-			onBackPressed();
-			return true;
-		}
-		return super.onOptionsItemSelected(item);
-	}
-
-	@Override
-	public void onBackPressed() {
-		if (viewModel.getState()
-				.getValue() instanceof ReturnShardState.Failed) {
-			// re-create this activity when going back in failed state
-			Intent i = new Intent(this, ReturnShardActivity.class);
-			i.setFlags(FLAG_ACTIVITY_CLEAR_TOP);
-			startActivity(i);
-		} else {
-			super.onBackPressed();
-		}
-	}
-
-	private void requestBluetoothDiscoverable() {
-		if (!viewModel.isBluetoothSupported()) {
-			viewModel.setBluetoothDecision(
-					ReturnShardViewModel.BluetoothDecision.NO_ADAPTER);
-		} else {
-			Intent i = new Intent(ACTION_REQUEST_DISCOVERABLE);
-			if (i.resolveActivity(getPackageManager()) != null) {
-				LOG.info("Asking for Bluetooth discoverability");
-				viewModel.setBluetoothDecision(
-						ReturnShardViewModel.BluetoothDecision.WAITING);
-				bluetoothLauncher.launch(120); // 2min discoverable
-			} else {
-				viewModel.setBluetoothDecision(
-						ReturnShardViewModel.BluetoothDecision.NO_ADAPTER);
-			}
-		}
-	}
-
-	private void showQrCodeFragment() {
-		// FIXME #824
-		FragmentManager fm = getSupportFragmentManager();
-		if (fm.findFragmentByTag(ReturnShardFragment.TAG) == null) {
-			BaseFragment f = ReturnShardFragment.newInstance();
-			fm.beginTransaction()
-					.replace(R.id.fragmentContainer, f, f.getUniqueTag())
-					.addToBackStack(f.getUniqueTag())
-					.commit();
-		}
-	}
-
-	private void onReturnShardStateChanged(ReturnShardState state) {
-		if (state instanceof ReturnShardState.SocialBackupExchangeFinished) {
-			ReturnShardState.SocialBackupExchangeResult result =
-					((ReturnShardState.SocialBackupExchangeFinished) state).result;
-			onSocialBackupExchangeResult(result);
-		} else if (state instanceof ReturnShardState.Failed) {
-			Boolean qrCodeTooOld =
-					((ReturnShardState.Failed) state).qrCodeTooOld;
-			onAddingContactFailed(qrCodeTooOld);
-		}
-	}
-
-	private void onSocialBackupExchangeResult(
-			ReturnShardState.SocialBackupExchangeResult result) {
-		if (result instanceof ReturnShardState.SocialBackupExchangeResult.Success) {
-//			String text = getString(R.string.contact_added_toast, contactName);
-			Toast.makeText(this, "Shard return successful", LENGTH_LONG).show();
-			supportFinishAfterTransition();
-		} else if (result instanceof ReturnShardState.SocialBackupExchangeResult.Error) {
-			showErrorFragment();
-		} else throw new AssertionError();
-	}
-
-	private void onAddingContactFailed(@Nullable Boolean qrCodeTooOld) {
-		if (qrCodeTooOld == null) {
-			showErrorFragment();
-		} else {
-			String msg;
-			if (qrCodeTooOld) {
-				msg = getString(R.string.qr_code_too_old,
-						getString(R.string.app_name));
-			} else {
-				msg = getString(R.string.qr_code_too_new,
-						getString(R.string.app_name));
-			}
-			showNextFragment(AddNearbyContactErrorFragment.newInstance(msg));
-		}
-	}
-
-	private void showErrorFragment() {
-		showNextFragment(new AddNearbyContactErrorFragment());
-	}
-
-	@Override
-	@Deprecated
-	public void runOnDbThread(Runnable runnable) {
-		throw new RuntimeException("Don't use this deprecated method here.");
-	}
-}

briar-android/src/main/java/org/briarproject/briar/android/socialbackup/recover/ReturnShardState.java

@@ -1,76 +0,0 @@
-package org.briarproject.briar.android.socialbackup.recover;
-
-import android.graphics.Bitmap;
-
-import org.briarproject.bramble.api.identity.Author;
-
-import androidx.annotation.Nullable;
-
-abstract class ReturnShardState {
-
-	static class KeyAgreementListening extends
-			ReturnShardState {
-		final Bitmap qrCode;
-
-		KeyAgreementListening(Bitmap qrCode) {
-			this.qrCode = qrCode;
-		}
-	}
-
-	static class QrCodeScanned extends
-			ReturnShardState {
-	}
-
-	static class KeyAgreementWaiting extends ReturnShardState {
-	}
-
-	static class KeyAgreementStarted extends ReturnShardState {
-	}
-
-	static class SocialBackupExchangeStarted extends ReturnShardState {
-	}
-
-	static class SocialBackupExchangeFinished extends ReturnShardState {
-		final SocialBackupExchangeResult
-				result;
-
-		SocialBackupExchangeFinished(
-				SocialBackupExchangeResult result) {
-			this.result = result;
-		}
-	}
-
-	static class Failed extends ReturnShardState {
-		/**
-		 * Non-null if failed due to the scanned QR code version.
-		 * True if the app producing the code is too old.
-		 * False if the scanning app is too old.
-		 */
-		@Nullable
-		final Boolean qrCodeTooOld;
-
-		Failed(@Nullable Boolean qrCodeTooOld) {
-			this.qrCodeTooOld = qrCodeTooOld;
-		}
-
-		Failed() {
-			this(null);
-		}
-	}
-
-	abstract static class SocialBackupExchangeResult {
-		static class Success extends SocialBackupExchangeResult {
-			Success() {}
-		}
-
-		static class Error extends SocialBackupExchangeResult {
-			@Nullable
-			final Author duplicateAuthor;
-
-			Error(@Nullable Author duplicateAuthor) {
-				this.duplicateAuthor = duplicateAuthor;
-			}
-		}
-	} // end ContactExchangeResult
-
-}

briar-android/src/main/java/org/briarproject/briar/android/socialbackup/recover/ReturnShardViewModel.java

@@ -1,545 +0,0 @@
-package org.briarproject.briar.android.socialbackup.recover;
-
-import android.app.Application;
-import android.bluetooth.BluetoothAdapter;
-import android.content.BroadcastReceiver;
-import android.content.Context;
-import android.content.Intent;
-import android.content.IntentFilter;
-import android.graphics.Bitmap;
-import android.util.DisplayMetrics;
-import android.widget.Toast;
-
-import com.google.zxing.Result;
-
-import org.briarproject.bramble.api.UnsupportedVersionException;
-import org.briarproject.bramble.api.connection.ConnectionManager;
-import org.briarproject.bramble.api.contact.Contact;
-import org.briarproject.bramble.api.contact.ContactExchangeManager;
-import org.briarproject.bramble.api.crypto.SecretKey;
-import org.briarproject.bramble.api.db.ContactExistsException;
-import org.briarproject.bramble.api.db.DbException;
-import org.briarproject.bramble.api.event.Event;
-import org.briarproject.bramble.api.event.EventBus;
-import org.briarproject.bramble.api.event.EventListener;
-import org.briarproject.bramble.api.keyagreement.KeyAgreementResult;
-import org.briarproject.bramble.api.keyagreement.KeyAgreementTask;
-import org.briarproject.bramble.api.keyagreement.Payload;
-import org.briarproject.bramble.api.keyagreement.PayloadEncoder;
-import org.briarproject.bramble.api.keyagreement.PayloadParser;
-import org.briarproject.bramble.api.keyagreement.event.KeyAgreementAbortedEvent;
-import org.briarproject.bramble.api.keyagreement.event.KeyAgreementFailedEvent;
-import org.briarproject.bramble.api.keyagreement.event.KeyAgreementFinishedEvent;
-import org.briarproject.bramble.api.keyagreement.event.KeyAgreementListeningEvent;
-import org.briarproject.bramble.api.keyagreement.event.KeyAgreementStartedEvent;
-import org.briarproject.bramble.api.keyagreement.event.KeyAgreementWaitingEvent;
-import org.briarproject.bramble.api.lifecycle.IoExecutor;
-import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
-import org.briarproject.bramble.api.plugin.BluetoothConstants;
-import org.briarproject.bramble.api.plugin.LanTcpConstants;
-import org.briarproject.bramble.api.plugin.Plugin;
-import org.briarproject.bramble.api.plugin.PluginManager;
-import org.briarproject.bramble.api.plugin.TransportId;
-import org.briarproject.bramble.api.plugin.duplex.DuplexTransportConnection;
-import org.briarproject.bramble.api.plugin.event.TransportStateEvent;
-import org.briarproject.bramble.api.system.AndroidExecutor;
-import org.briarproject.briar.R;
-import org.briarproject.briar.android.contact.add.nearby.QrCodeDecoder;
-import org.briarproject.briar.android.contact.add.nearby.QrCodeUtils;
-import org.briarproject.briar.android.viewmodel.LiveEvent;
-import org.briarproject.briar.android.viewmodel.MutableLiveEvent;
-import org.briarproject.briar.api.socialbackup.ReturnShardPayload;
-import org.briarproject.briar.api.socialbackup.SocialBackupExchangeManager;
-import org.briarproject.briar.api.socialbackup.SocialBackupManager;
-
-import java.io.IOException;
-import java.nio.charset.Charset;
-import java.util.concurrent.Executor;
-import java.util.logging.Logger;
-
-import javax.inject.Inject;
-import javax.inject.Provider;
-
-import androidx.annotation.Nullable;
-import androidx.annotation.UiThread;
-import androidx.lifecycle.AndroidViewModel;
-import androidx.lifecycle.LiveData;
-import androidx.lifecycle.MutableLiveData;
-
-import static android.bluetooth.BluetoothAdapter.ACTION_SCAN_MODE_CHANGED;
-import static android.bluetooth.BluetoothAdapter.EXTRA_SCAN_MODE;
-import static android.bluetooth.BluetoothAdapter.SCAN_MODE_CONNECTABLE_DISCOVERABLE;
-import static android.widget.Toast.LENGTH_LONG;
-import static java.util.Objects.requireNonNull;
-import static java.util.logging.Level.INFO;
-import static java.util.logging.Level.WARNING;
-import static java.util.logging.Logger.getLogger;
-import static org.briarproject.bramble.api.plugin.Plugin.State.ACTIVE;
-import static org.briarproject.bramble.api.plugin.Plugin.State.DISABLED;
-import static org.briarproject.bramble.api.plugin.Plugin.State.INACTIVE;
-import static org.briarproject.bramble.api.plugin.Plugin.State.STARTING_STOPPING;
-import static org.briarproject.bramble.util.LogUtils.logException;
-import static org.briarproject.briar.android.contact.add.nearby.AddNearbyContactPermissionManager.areEssentialPermissionsGranted;
-
-@NotNullByDefault
-class ReturnShardViewModel extends AndroidViewModel
-		implements EventListener, QrCodeDecoder.ResultCallback {
-
-	private static final Logger LOG =
-			getLogger(ReturnShardViewModel.class.getName());
-
-	// TODO deduplicate
-	enum BluetoothDecision {
-		/**
-		 * We haven't asked the user about Bluetooth discoverability.
-		 */
-		UNKNOWN,
-
-		/**
-		 * The device doesn't have a Bluetooth adapter.
-		 */
-		NO_ADAPTER,
-
-		/**
-		 * We're waiting for the user to accept or refuse discoverability.
-		 */
-		WAITING,
-
-		/**
-		 * The user has accepted discoverability.
-		 */
-		ACCEPTED,
-
-		/**
-		 * The user has refused discoverability.
-		 */
-		REFUSED
-	}
-
-	@SuppressWarnings("CharsetObjectCanBeUsed") // Requires minSdkVersion >= 19
-	private static final Charset ISO_8859_1 = Charset.forName("ISO-8859-1");
-
-	private boolean sending;
-	private ReturnShardPayload returnShardPayload;
-
-	private final EventBus eventBus;
-	private final AndroidExecutor androidExecutor;
-	private final Executor ioExecutor;
-	private final PluginManager pluginManager;
-	private final PayloadEncoder payloadEncoder;
-	private final PayloadParser payloadParser;
-	private final Provider<KeyAgreementTask> keyAgreementTaskProvider;
-	private final SocialBackupExchangeManager socialBackupExchangeManager;
-	private final SocialBackupManager socialBackupManager;
-	private final ConnectionManager connectionManager;
-
-	private final MutableLiveEvent<Boolean> checkPermissions =
-			new MutableLiveEvent<>();
-	private final MutableLiveEvent<Boolean> requestBluetoothDiscoverable =
-			new MutableLiveEvent<>();
-	private final MutableLiveEvent<Boolean> showQrCodeFragment =
-			new MutableLiveEvent<>();
-	private final MutableLiveData<ReturnShardState> state =
-			new MutableLiveData<>();
-
-	final QrCodeDecoder qrCodeDecoder;
-	final BroadcastReceiver
-			bluetoothReceiver = new BluetoothStateReceiver();
-
-	@Nullable
-	private final BluetoothAdapter bt;
-	@Nullable
-	private final Plugin wifiPlugin, bluetoothPlugin;
-
-	// UiThread
-	private BluetoothDecision
-			bluetoothDecision = BluetoothDecision.UNKNOWN;
-
-	private boolean wasContinueClicked = false;
-	private boolean isActivityResumed = false;
-
-	/**
-	 * Records whether we've enabled the wifi plugin so we don't enable it more
-	 * than once.
-	 */
-	private boolean hasEnabledWifi = false;
-
-	/**
-	 * Records whether we've enabled the Bluetooth plugin so we don't enable it
-	 * more than once.
-	 */
-	private boolean hasEnabledBluetooth = false;
-
-	@Nullable
-	private KeyAgreementTask task;
-	private volatile boolean gotLocalPayload = false, gotRemotePayload = false;
-
-	@Inject
-	ReturnShardViewModel(Application app,
-			EventBus eventBus,
-			AndroidExecutor androidExecutor,
-			@IoExecutor Executor ioExecutor,
-			PluginManager pluginManager,
-			PayloadEncoder payloadEncoder,
-			PayloadParser payloadParser,
-			Provider<KeyAgreementTask> keyAgreementTaskProvider,
-			SocialBackupExchangeManager socialBackupExchangeManager,
-			SocialBackupManager socialBackupManager,
-			ConnectionManager connectionManager) {
-		super(app);
-		this.eventBus = eventBus;
-		this.androidExecutor = androidExecutor;
-		this.ioExecutor = ioExecutor;
-		this.pluginManager = pluginManager;
-		this.payloadEncoder = payloadEncoder;
-		this.payloadParser = payloadParser;
-		this.keyAgreementTaskProvider = keyAgreementTaskProvider;
-		this.socialBackupExchangeManager = socialBackupExchangeManager;
-		this.socialBackupManager = socialBackupManager;
-		this.connectionManager = connectionManager;
-		bt = BluetoothAdapter.getDefaultAdapter();
-		wifiPlugin = pluginManager.getPlugin(LanTcpConstants.ID);
-		bluetoothPlugin = pluginManager.getPlugin(BluetoothConstants.ID);
-		qrCodeDecoder = new QrCodeDecoder(androidExecutor, ioExecutor, this);
-		eventBus.addListener(this);
-		IntentFilter filter = new IntentFilter(ACTION_SCAN_MODE_CHANGED);
-		getApplication().registerReceiver(bluetoothReceiver, filter);
-	}
-
-	@Override
-	protected void onCleared() {
-		super.onCleared();
-		getApplication().unregisterReceiver(bluetoothReceiver);
-		eventBus.removeListener(this);
-		stopListening();
-	}
-
-	@UiThread
-	void onContinueClicked() {
-		if (bluetoothDecision == BluetoothDecision.REFUSED) {
-			bluetoothDecision = BluetoothDecision.UNKNOWN; // Ask again
-		}
-		wasContinueClicked = true;
-		checkPermissions.setEvent(true);
-		showQrCodeFragmentIfAllowed();
-	}
-
-	@UiThread
-	boolean isBluetoothSupported() {
-		return bt != null && bluetoothPlugin != null;
-	}
-
-	@UiThread
-	boolean isWifiReady() {
-		if (wifiPlugin == null) return true; // Continue without wifi
-		Plugin.State state = wifiPlugin.getState();
-		// Wait for plugin to become enabled
-		return state == ACTIVE || state == INACTIVE;
-	}
-
-	@UiThread
-	boolean isBluetoothReady() {
-		if (bt == null || bluetoothPlugin == null) {
-			// Continue without Bluetooth
-			return true;
-		}
-		if (bluetoothDecision == BluetoothDecision.UNKNOWN ||
-				bluetoothDecision == BluetoothDecision.WAITING ||
-				bluetoothDecision == BluetoothDecision.REFUSED) {
-			// Wait for user to accept
-			return false;
-		}
-		if (bt.getScanMode() != SCAN_MODE_CONNECTABLE_DISCOVERABLE) {
-			// Wait for adapter to become discoverable
-			return false;
-		}
-		// Wait for plugin to become active
-		return bluetoothPlugin.getState() == ACTIVE;
-	}
-
-	@UiThread
-	void enableWifiIfWeShould() {
-		if (hasEnabledWifi) return;
-		if (wifiPlugin == null) return;
-		Plugin.State state = wifiPlugin.getState();
-		if (state == STARTING_STOPPING || state == DISABLED) {
-			LOG.info("Enabling wifi plugin");
-			hasEnabledWifi = true;
-			pluginManager.setPluginEnabled(LanTcpConstants.ID, true);
-		}
-	}
-
-	@UiThread
-	void enableBluetoothIfWeShould() {
-		if (bluetoothDecision != BluetoothDecision.ACCEPTED)
-			return;
-		if (hasEnabledBluetooth) return;
-		if (bluetoothPlugin == null || !isBluetoothSupported()) return;
-		Plugin.State state = bluetoothPlugin.getState();
-		if (state == STARTING_STOPPING || state == DISABLED) {
-			LOG.info("Enabling Bluetooth plugin");
-			hasEnabledBluetooth = true;
-			pluginManager.setPluginEnabled(BluetoothConstants.ID, true);
-		}
-	}
-
-	@UiThread
-	void startAddingContact() {
-		// If we return to the intro fragment, the continue button needs to be
-		// clicked again before showing the QR code fragment
-		wasContinueClicked = false;
-		// If we return to the intro fragment, ask for Bluetooth
-		// discoverability again before showing the QR code fragment
-		bluetoothDecision = BluetoothDecision.UNKNOWN;
-		// If we return to the intro fragment, we may need to enable wifi and
-		// Bluetooth again
-		hasEnabledWifi = false;
-		hasEnabledBluetooth = false;
-		// start to listen with a KeyAgreementTask
-		startListening();
-		showQrCodeFragment.setEvent(true);
-	}
-
-	/**
-	 * Call this once Bluetooth and Wi-Fi are ready to be used.
-	 * It is possible to call this more than once over the ViewModel's lifetime.
-	 */
-	@UiThread
-	private void startListening() {
-		KeyAgreementTask oldTask = task;
-		KeyAgreementTask newTask = keyAgreementTaskProvider.get();
-		task = newTask;
-		ioExecutor.execute(() -> {
-			if (oldTask != null) oldTask.stopListening();
-			newTask.listen();
-		});
-	}
-
-	@UiThread
-	private void stopListening() {
-		KeyAgreementTask oldTask = task;
-		ioExecutor.execute(() -> {
-			if (oldTask != null) oldTask.stopListening();
-		});
-	}
-
-	@Override
-	public void eventOccurred(Event e) {
-		if (e instanceof TransportStateEvent) {
-			TransportStateEvent t = (TransportStateEvent) e;
-			if (t.getTransportId().equals(BluetoothConstants.ID)) {
-				if (LOG.isLoggable(INFO)) {
-					LOG.info("Bluetooth state changed to " + t.getState());
-				}
-				showQrCodeFragmentIfAllowed();
-			} else if (t.getTransportId().equals(LanTcpConstants.ID)) {
-				if (LOG.isLoggable(INFO)) {
-					LOG.info("Wifi state changed to " + t.getState());
-				}
-				showQrCodeFragmentIfAllowed();
-			}
-		} else if (e instanceof KeyAgreementListeningEvent) {
-			LOG.info("KeyAgreementListeningEvent received");
-			KeyAgreementListeningEvent event = (KeyAgreementListeningEvent) e;
-			onLocalPayloadReceived(event.getLocalPayload());
-		} else if (e instanceof KeyAgreementWaitingEvent) {
-			LOG.info("KeyAgreementWaitingEvent received");
-			state.setValue(new ReturnShardState.KeyAgreementWaiting());
-		} else if (e instanceof KeyAgreementStartedEvent) {
-			LOG.info("KeyAgreementStartedEvent received");
-			state.setValue(new ReturnShardState.KeyAgreementStarted());
-		} else if (e instanceof KeyAgreementFinishedEvent) {
-			LOG.info("KeyAgreementFinishedEvent received");
-			KeyAgreementResult result =
-					((KeyAgreementFinishedEvent) e).getResult();
-			startContactExchange(result);
-			state.setValue(new ReturnShardState.SocialBackupExchangeStarted());
-		} else if (e instanceof KeyAgreementAbortedEvent) {
-			LOG.info("KeyAgreementAbortedEvent received");
-			resetPayloadFlags();
-			state.setValue(new ReturnShardState.Failed());
-		} else if (e instanceof KeyAgreementFailedEvent) {
-			LOG.info("KeyAgreementFailedEvent received");
-			resetPayloadFlags();
-			state.setValue(new ReturnShardState.Failed());
-		}
-	}
-
-	@SuppressWarnings("StatementWithEmptyBody")
-	@UiThread
-	void showQrCodeFragmentIfAllowed() {
-		boolean permissionsGranted = areEssentialPermissionsGranted(
-				getApplication(), isBluetoothSupported());
-		if (isActivityResumed && wasContinueClicked && permissionsGranted) {
-			if (isWifiReady() && isBluetoothReady()) {
-				LOG.info("Wifi and Bluetooth are ready");
-				startAddingContact();
-			} else {
-				enableWifiIfWeShould();
-				if (bluetoothDecision == BluetoothDecision.UNKNOWN) {
-					requestBluetoothDiscoverable.setEvent(true);
-				} else if (bluetoothDecision == BluetoothDecision.REFUSED) {
-					// Ask again when the user clicks "continue"
-				} else {
-					enableBluetoothIfWeShould();
-				}
-			}
-		}
-	}
-
-	/**
-	 * This sets the QR code by setting the state to KeyAgreementListening.
-	 */
-	private void onLocalPayloadReceived(Payload localPayload) {
-		if (gotLocalPayload) return;
-		DisplayMetrics dm = getApplication().getResources().getDisplayMetrics();
-		ioExecutor.execute(() -> {
-			byte[] payloadBytes = payloadEncoder.encode(localPayload);
-			if (LOG.isLoggable(INFO)) {
-				LOG.info("Local payload is " + payloadBytes.length
-						+ " bytes");
-			}
-			// Use ISO 8859-1 to encode bytes directly as a string
-			String content = new String(payloadBytes, ISO_8859_1);
-			Bitmap qrCode = QrCodeUtils.createQrCode(dm, content);
-			gotLocalPayload = true;
-			state.postValue(new ReturnShardState.KeyAgreementListening(qrCode));
-		});
-	}
-
-	@Override
-	@IoExecutor
-	public void onQrCodeDecoded(Result result) {
-		LOG.info("Got result from decoder"+gotLocalPayload+gotRemotePayload);
-		// Ignore results until the KeyAgreementTask is ready
-		if (!gotLocalPayload || gotRemotePayload) return;
-		try {
-			byte[] payloadBytes = result.getText().getBytes(ISO_8859_1);
-			if (LOG.isLoggable(INFO))
-				LOG.info("Remote payload is " + payloadBytes.length + " bytes");
-			Payload remotePayload = payloadParser.parse(payloadBytes);
-			gotRemotePayload = true;
-			requireNonNull(task).connectAndRunProtocol(remotePayload);
-			state.postValue(new ReturnShardState.QrCodeScanned());
-		} catch (UnsupportedVersionException e) {
-			resetPayloadFlags();
-			state.postValue(new ReturnShardState.Failed(e.isTooOld()));
-		} catch (IOException | IllegalArgumentException e) {
-			LOG.log(WARNING, "QR Code Invalid", e);
-			androidExecutor.runOnUiThread(() -> Toast.makeText(getApplication(),
-					R.string.qr_code_invalid, LENGTH_LONG).show());
-			resetPayloadFlags();
-			state.postValue(new ReturnShardState.Failed());
-		}
-	}
-
-	private void resetPayloadFlags() {
-		gotRemotePayload = false;
-		gotLocalPayload = false;
-	}
-
-	@UiThread
-	private void startContactExchange(KeyAgreementResult result) {
-		TransportId t = result.getTransportId();
-		DuplexTransportConnection conn = result.getConnection();
-		SecretKey masterKey = result.getMasterKey();
-		boolean alice = result.wasAlice();
-		ioExecutor.execute(() -> {
-			try {
-				if (sending) {
-					socialBackupExchangeManager.sendReturnShard(conn, masterKey, alice, returnShardPayload);
-				} else {
-					returnShardPayload = socialBackupExchangeManager.receiveReturnShard(conn, masterKey, alice);
-				}
-				ReturnShardState.SocialBackupExchangeResult.Success
-						success =
-						new ReturnShardState.SocialBackupExchangeResult.Success();
-				state.postValue(
-						new ReturnShardState.SocialBackupExchangeFinished(success));
-			} catch (ContactExistsException e) {
-				tryToClose(conn);
-				ReturnShardState.SocialBackupExchangeResult.Error
-						error = new ReturnShardState.SocialBackupExchangeResult.Error(
-						e.getRemoteAuthor());
-				state.postValue(
-						new ReturnShardState.SocialBackupExchangeFinished(error));
-			} catch (DbException | IOException e) {
-				tryToClose(conn);
-				logException(LOG, WARNING, e);
-				ReturnShardState.SocialBackupExchangeResult.Error
-						error =
-						new ReturnShardState.SocialBackupExchangeResult.Error(null);
-				state.postValue(
-						new ReturnShardState.SocialBackupExchangeFinished(error));
-			}
-		});
-	}
-
-	private class BluetoothStateReceiver extends BroadcastReceiver {
-		@UiThread
-		@Override
-		public void onReceive(Context context, Intent intent) {
-			int scanMode = intent.getIntExtra(EXTRA_SCAN_MODE, -1);
-			LOG.info("Bluetooth scan mode changed: " + scanMode);
-			showQrCodeFragmentIfAllowed();
-		}
-	}
-
-	private void tryToClose(DuplexTransportConnection conn) {
-		try {
-			conn.getReader().dispose(true, true);
-			conn.getWriter().dispose(true);
-		} catch (IOException e) {
-			logException(LOG, WARNING, e);
-		}
-	}
-
-	/**
-	 * Set to true in onPostResume() and false in onPause(). This prevents the
-	 * QR code fragment from being shown if onRequestPermissionsResult() is
-	 * called while the activity is paused, which could cause a crash due to
-	 * https://issuetracker.google.com/issues/37067655.
-	 * TODO check if this is still happening with new permission requesting
-	 */
-	@UiThread
-	void setIsActivityResumed(boolean resumed) {
-		isActivityResumed = resumed;
-		// Workaround for
-		// https://code.google.com/p/android/issues/detail?id=190966
-		showQrCodeFragmentIfAllowed();
-	}
-
-	@UiThread
-	void setBluetoothDecision(BluetoothDecision decision) {
-		bluetoothDecision = decision;
-		showQrCodeFragmentIfAllowed();
-	}
-
-	LiveEvent<Boolean> getCheckPermissions() {
-		return checkPermissions;
-	}
-
-	LiveEvent<Boolean> getRequestBluetoothDiscoverable() {
-		return requestBluetoothDiscoverable;
-	}
-
-	LiveEvent<Boolean> getShowQrCodeFragment() {
-		return showQrCodeFragment;
-	}
-
-	LiveData<ReturnShardState> getState() {
-		return state;
-	}
-
-    public void setSending(boolean sending) {
-		this.sending = sending;
-    }
-
-    public void setReturnShardPayload(ReturnShardPayload returnShardPayload) {
-		this.returnShardPayload = returnShardPayload;
-    }
-
-	QrCodeDecoder getQrCodeDecoder() {
-		return qrCodeDecoder;
-	}
-}

briar-android/src/main/res/layout/fragment_recovery_custodian_done.xml

@@ -10,6 +10,17 @@
 	android:paddingRight="@dimen/margin_large"
 	android:paddingBottom="@dimen/margin_medium">
 
+	<Button
+		android:id="@+id/button"
+		android:layout_width="wrap_content"
+		android:layout_height="wrap_content"
+		android:layout_marginTop="32dp"
+		android:text="@string/backup_done_dismiss"
+		android:textSize="24sp"
+		app:layout_constraintEnd_toEndOf="parent"
+		app:layout_constraintStart_toStartOf="parent"
+		app:layout_constraintTop_toBottomOf="@+id/textView2" />
+
 	<TextView
 		android:id="@+id/textView2"
 		android:layout_width="wrap_content"

briar-android/src/main/res/values/strings.xml

@@ -675,13 +675,13 @@
 
 	<!-- recovery from the secret owner's POV -->
 
-	<string name="recovery_explainer">You need to meet your trusted contacts in-person to receive pieces by scanning QR codes</string>
+	<string name="recovery_explainer">You need to meet your trusted contacts in-person to receive pieces</string>
 	<string name="recovery_begin">Begin</string>
 	<string name="recovery_failed_to_receive">Failed to receive backup piece</string>
 	<string name="recovery_helpful_suggestions">Please check that bluetooth is swtiched on and that no-one but your trusted contact is able to scan the QR code</string>
 	<string name="recovery_retry">Retry</string>
 	<string name="recovery_recovered_shards">Recovered backup pieces:</string>
-	<string name="recovery_scan_qr_code">Scan QR code</string>
+	<string name="recovery_scan_qr_code">Show QR code</string>
 	<string name="recovery_recovering_account">Recovering account…</string>
 	<string name="recovery_shard_received">Account backup piece received</string>
 	<string name="recovery_account_recovered">Account recovered</string>

briar-api/src/main/java/org/briarproject/briar/api/socialbackup/ReturnShardPayload.java

@@ -1,15 +1,34 @@
 package org.briarproject.briar.api.socialbackup;
 
+import org.briarproject.bramble.api.FormatException;
+import org.briarproject.bramble.api.data.BdfList;
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 
 import javax.annotation.concurrent.Immutable;
 
+import static org.briarproject.bramble.util.ValidationUtils.checkSize;
+
 @Immutable
 @NotNullByDefault
 public class ReturnShardPayload {
 	private final Shard shard;
 	private final BackupPayload backupPayload;
 
+	// TODO this does not belong here
+	private static Shard parseShardMessage(BdfList body) throws FormatException {
+		// Message type, secret ID, shard
+		byte[] secretId = body.getRaw(1);
+		byte[] shard = body.getRaw(2);
+		return new Shard(secretId, shard);
+	}
+
+	public static ReturnShardPayload fromList(BdfList body) throws FormatException {
+		checkSize(body, 2);
+		Shard shard = parseShardMessage(body.getList(0));
+		BackupPayload backupPayload = new BackupPayload(body.getRaw(1));
+		return new ReturnShardPayload(shard, backupPayload);
+	}
+
 	public ReturnShardPayload(Shard shard, BackupPayload backupPayload) {
 		this.shard = shard;
 		this.backupPayload = backupPayload;
@@ -22,4 +41,9 @@ public class ReturnShardPayload {
 	public BackupPayload getBackupPayload() {
 		return backupPayload;
 	}
+
+	public boolean equals(ReturnShardPayload otherReturnShardPayload) {
+		return shard.equals(otherReturnShardPayload.getShard()) && backupPayload
+				.equals(otherReturnShardPayload.getBackupPayload());
+	}
 }

briar-api/src/main/java/org/briarproject/briar/api/socialbackup/Shard.java

@@ -2,6 +2,8 @@ package org.briarproject.briar.api.socialbackup;
 
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 
+import java.util.Arrays;
+
 import javax.annotation.concurrent.Immutable;
 
 @Immutable
@@ -22,4 +24,9 @@ public class Shard {
 	public byte[] getShard() {
 		return shard;
 	}
+
+	public boolean equals(Shard otherShard) {
+		return Arrays.equals(secretId, otherShard.getSecretId()) &&
+				Arrays.equals(shard, otherShard.getShard());
+	}
 }

briar-api/src/main/java/org/briarproject/briar/api/socialbackup/recovery/CustodianTask.java

@@ -0,0 +1,53 @@
+package org.briarproject.briar.api.socialbackup.recovery;
+
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+
+@NotNullByDefault
+public interface CustodianTask {
+
+	void start(Observer observer, byte[] payload);
+
+	void cancel();
+
+	void qrCodeDecoded(byte[] qrCodePayload);
+
+	interface Observer {
+		void onStateChanged(State state);
+	}
+
+	class State {
+
+		public static class Connecting extends State {
+		}
+
+		public static class SendingShard extends State {
+		}
+
+		public static class ReceivingAck extends State {
+		}
+
+		public static class Success extends State {
+		}
+
+		public static class Failure extends State {
+
+			public enum Reason {
+				QR_CODE_INVALID,
+				QR_CODE_TOO_OLD,
+				QR_CODE_TOO_NEW,
+				NO_CONNECTION,
+				OTHER
+			}
+
+			private final Reason reason;
+
+			public Failure(Reason reason) {
+				this.reason = reason;
+			}
+
+			public Reason getReason() {
+				return reason;
+			}
+		}
+	}
+}

briar-api/src/main/java/org/briarproject/briar/api/socialbackup/recovery/SecretOwnerTask.java

@@ -0,0 +1,70 @@
+package org.briarproject.briar.api.socialbackup.recovery;
+
+import org.briarproject.bramble.api.crypto.PublicKey;
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+import org.briarproject.briar.api.socialbackup.ReturnShardPayload;
+
+import java.net.InetAddress;
+import java.net.InetSocketAddress;
+
+@NotNullByDefault
+public interface SecretOwnerTask {
+
+	void start(Observer observer, InetAddress inetAddress);
+
+	void cancel();
+
+	interface Observer {
+		void onStateChanged(State state);
+	}
+
+	class State {
+
+		public static class Listening extends State {
+
+			private final byte[] localPayload;
+
+			public Listening(byte[] localPayload) {
+				this.localPayload = localPayload;
+			}
+
+			public byte[] getLocalPayload() {
+				return localPayload;
+			}
+		}
+
+		public static class ReceivingShard extends State {
+		}
+
+		public static class SendingAck extends State {
+		}
+
+		public static class Success extends State {
+			private final ReturnShardPayload remotePayload;
+
+			public Success(ReturnShardPayload remotePayload) { this.remotePayload = remotePayload; }
+
+			public ReturnShardPayload getRemotePayload() { return remotePayload; }
+		}
+
+		public static class Failure extends State {
+
+			public enum Reason {
+				CANCELLED,
+				SECURITY,
+				NO_CONNECTION,
+				OTHER
+			}
+
+			private final Reason reason;
+
+			public Failure(Reason reason) {
+				this.reason = reason;
+			}
+
+			public Reason getReason() {
+				return reason;
+			}
+		}
+	}
+}

briar-core/src/main/java/org/briarproject/briar/socialbackup/BackupPayloadDecoder.java

@@ -0,0 +1,16 @@
+package org.briarproject.briar.socialbackup;
+
+import org.briarproject.bramble.api.FormatException;
+import org.briarproject.bramble.api.crypto.SecretKey;
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+import org.briarproject.briar.api.socialbackup.BackupPayload;
+
+import java.security.GeneralSecurityException;
+
+@NotNullByDefault
+public interface BackupPayloadDecoder {
+	SocialBackup decodeBackupPayload(
+			SecretKey secret,
+			BackupPayload backupPayload) throws FormatException,
+			GeneralSecurityException;
+}

briar-core/src/main/java/org/briarproject/briar/socialbackup/BackupPayloadDecoderImpl.java

@@ -0,0 +1,150 @@
+package org.briarproject.briar.socialbackup;
+
+import org.briarproject.bramble.api.FormatException;
+import org.briarproject.bramble.api.client.ClientHelper;
+import org.briarproject.bramble.api.contact.Contact;
+import org.briarproject.bramble.api.contact.ContactId;
+import org.briarproject.bramble.api.crypto.AgreementPrivateKey;
+import org.briarproject.bramble.api.crypto.AgreementPublicKey;
+import org.briarproject.bramble.api.crypto.AuthenticatedCipher;
+import org.briarproject.bramble.api.crypto.PrivateKey;
+import org.briarproject.bramble.api.crypto.PublicKey;
+import org.briarproject.bramble.api.crypto.SecretKey;
+import org.briarproject.bramble.api.crypto.SignaturePrivateKey;
+import org.briarproject.bramble.api.data.BdfList;
+import org.briarproject.bramble.api.identity.Author;
+import org.briarproject.bramble.api.identity.Identity;
+import org.briarproject.bramble.api.identity.LocalAuthor;
+import org.briarproject.bramble.api.plugin.TransportId;
+import org.briarproject.bramble.api.properties.TransportProperties;
+import org.briarproject.briar.api.socialbackup.BackupPayload;
+import org.briarproject.briar.api.socialbackup.MessageParser;
+import org.briarproject.briar.api.socialbackup.Shard;
+
+import java.security.GeneralSecurityException;
+import java.security.SecureRandom;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Map;
+import java.util.logging.Logger;
+
+import javax.inject.Inject;
+import javax.inject.Provider;
+
+import static java.util.logging.Logger.getLogger;
+import static org.briarproject.briar.socialbackup.SocialBackupConstants.AUTH_TAG_BYTES;
+import static org.briarproject.briar.socialbackup.SocialBackupConstants.NONCE_BYTES;
+
+public class BackupPayloadDecoderImpl implements BackupPayloadDecoder {
+	private final ClientHelper clientHelper;
+	private final Provider<AuthenticatedCipher> cipherProvider;
+	private final SecureRandom secureRandom;
+	private final MessageParser messageParser;
+	private static final Logger LOG =
+			getLogger(BackupPayloadDecoderImpl.class.getName());
+
+	@Inject
+	BackupPayloadDecoderImpl(ClientHelper clientHelper,
+			Provider<AuthenticatedCipher> cipherProvider,
+			SecureRandom secureRandom,
+			MessageParser messageParser) {
+		this.clientHelper = clientHelper;
+		this.cipherProvider = cipherProvider;
+		this.secureRandom = secureRandom;
+		this.messageParser = messageParser;
+	}
+
+	public SocialBackup decodeBackupPayload(
+			SecretKey secret,
+			BackupPayload backupPayload)
+			throws FormatException, GeneralSecurityException {
+
+		byte[] ciphertextWithNonce = backupPayload.getBytes();
+		byte[] nonce = new byte[NONCE_BYTES];
+		System.arraycopy(ciphertextWithNonce, 0, nonce, 0, NONCE_BYTES);
+
+		byte[] ciphertext = new byte[ciphertextWithNonce.length - NONCE_BYTES];
+		System.arraycopy(ciphertextWithNonce, nonce.length, ciphertext, 0,
+				ciphertext.length);
+
+		AuthenticatedCipher cipher = cipherProvider.get();
+		cipher.init(false, secret, nonce);
+		byte[] plaintext =
+				new byte[ciphertext.length - AUTH_TAG_BYTES];
+		int decrypted = cipher.process(ciphertext, 0,
+				ciphertext.length, plaintext, 0);
+		if (decrypted != plaintext.length) throw new AssertionError();
+		LOG.info("Backup payload decrypted");
+
+		BdfList backup = clientHelper.toList(plaintext);
+		int version = backup.getLong(0).intValue();
+		LOG.info("Backup payload has version number " + version);
+
+		BdfList bdfIdentity = backup.getList(1);
+		BdfList bdfContactData = backup.getList(2);
+
+		Author a = clientHelper
+				.parseAndValidateAuthor(bdfIdentity.getList(0));
+		PrivateKey signaturePrivateKey =
+				new SignaturePrivateKey(bdfIdentity.getRaw(1));
+		LocalAuthor localAuthor =
+				new LocalAuthor(a.getId(), a.getFormatVersion(), a.getName(),
+						a.getPublicKey(), signaturePrivateKey);
+		LOG.info("LocalAuthor parsed successfully. Name is " + a.getName());
+
+		PublicKey handshakePublicKey =
+				new AgreementPublicKey(bdfIdentity.getRaw(2));
+		PrivateKey handShakePrivateKey =
+				new AgreementPrivateKey(bdfIdentity.getRaw(3));
+
+		Long created = System.currentTimeMillis();
+
+		Identity identity = new Identity(localAuthor, handshakePublicKey,
+				handShakePrivateKey, created);
+		LOG.info("New identity created");
+
+		List<ContactData> contactDataList = new ArrayList();
+
+		for (int i = 0; i < bdfContactData.size(); i++) {
+			BdfList bdfData = bdfContactData.getList(i);
+
+			Author author =
+					clientHelper.parseAndValidateAuthor(bdfData.getList(0));
+			LOG.info("Contact author parsed");
+
+			String alias = bdfData.getOptionalString(1);
+			LOG.info("Contact alias is: " + alias);
+
+			// 2 - public key or null
+			byte[] handshakePublicKeyBytes = bdfData.getOptionalRaw(2);
+			PublicKey contactHandshakePublicKey = (handshakePublicKeyBytes == null)
+					? null
+					: new AgreementPublicKey(handshakePublicKeyBytes);
+			LOG.info("Contact handshake pk parsed");
+
+			// 3 - properties dictionary
+			Map<TransportId, TransportProperties> properties = clientHelper
+					.parseAndValidateTransportPropertiesMap(
+							bdfData.getDictionary(3));
+			LOG.info("Contact transport properties parsed");
+
+			// 4 shard or null
+			BdfList shardList = bdfData.getOptionalList(4);
+			Shard shard = (shardList == null) ? null :
+					messageParser.parseShardMessage(shardList);
+			// TODO validate shard
+		    LOG.info("Contact shard parsed");
+
+			ContactId contactId = new ContactId(i);
+			Contact contact =
+					new Contact(contactId, author, author.getId(), alias,
+							contactHandshakePublicKey, false);
+			ContactData contactData =
+					new ContactData(contact, properties, shard);
+			contactDataList.add(contactData);
+			LOG.info("Contact added");
+		}
+		LOG.info("All contacts added");
+		return new SocialBackup(identity, contactDataList, version);
+	}
+}

briar-core/src/main/java/org/briarproject/briar/socialbackup/BackupPayloadEncoderImpl.java

@@ -84,7 +84,10 @@ class BackupPayloadEncoderImpl implements BackupPayloadEncoder {
 			int encrypted = cipher.process(plaintext, 0, plaintext.length,
 					ciphertext, 0);
 			if (encrypted != ciphertext.length) throw new AssertionError();
-			return new org.briarproject.briar.api.socialbackup.BackupPayload(ciphertext);
+			byte[] ciphertextWithNonce = new byte[ciphertext.length + nonce.length];
+			System.arraycopy(nonce, 0, ciphertextWithNonce, 0, nonce.length);
+			System.arraycopy(ciphertext, 0, ciphertextWithNonce, nonce.length, ciphertext.length);
+			return new org.briarproject.briar.api.socialbackup.BackupPayload(ciphertextWithNonce);
 		} catch (FormatException | GeneralSecurityException e) {
 			throw new AssertionError(e);
 		}

briar-core/src/main/java/org/briarproject/briar/socialbackup/SocialBackup.java

@@ -0,0 +1,29 @@
+package org.briarproject.briar.socialbackup;
+
+import org.briarproject.bramble.api.identity.Identity;
+
+import java.util.List;
+
+public class SocialBackup {
+	private Identity identity;
+	private List<ContactData> contacts;
+	private int version;
+
+	SocialBackup (Identity identity, List<ContactData> contacts, int version) {
+		this.identity = identity;
+		this.contacts = contacts;
+		this.version = version;
+	}
+
+	public Identity getIdentity() {
+		return identity;
+	}
+
+	public List<ContactData> getContacts() {
+		return contacts;
+	}
+
+	public int getVersion() {
+		return version;
+	}
+}

briar-core/src/main/java/org/briarproject/briar/socialbackup/SocialBackupModule.java

@@ -10,6 +10,10 @@ import org.briarproject.bramble.api.versioning.ClientVersioningManager;
 import org.briarproject.briar.api.conversation.ConversationManager;
 import org.briarproject.briar.api.socialbackup.SocialBackupExchangeManager;
 import org.briarproject.briar.api.socialbackup.SocialBackupManager;
+import org.briarproject.briar.api.socialbackup.recovery.CustodianTask;
+import org.briarproject.briar.api.socialbackup.recovery.SecretOwnerTask;
+import org.briarproject.briar.socialbackup.recovery.CustodianTaskImpl;
+import org.briarproject.briar.socialbackup.recovery.SecretOwnerTaskImpl;
 
 import javax.inject.Inject;
 import javax.inject.Singleton;
@@ -83,17 +87,36 @@ public class SocialBackupModule {
 	}
 
 	@Provides
-	org.briarproject.briar.api.socialbackup.MessageEncoder messageEncoder(MessageEncoderImpl messageEncoder) {
+	BackupPayloadDecoder backupPayloadDecoder(
+			BackupPayloadDecoderImpl backupPayloadDecoder) {
+		return backupPayloadDecoder;
+	}
+
+	@Provides
+	org.briarproject.briar.api.socialbackup.MessageEncoder messageEncoder(
+			MessageEncoderImpl messageEncoder) {
 		return messageEncoder;
 	}
 
 	@Provides
-	org.briarproject.briar.api.socialbackup.MessageParser messageParser(MessageParserImpl messageParser) {
+	org.briarproject.briar.api.socialbackup.MessageParser messageParser(
+			MessageParserImpl messageParser) {
 		return messageParser;
 	}
 
 	@Provides
-	SocialBackupExchangeManager socialBackupExchangeManager(SocialBackupExchangeManagerImpl socialBackupExchangeManager) {
+	SocialBackupExchangeManager socialBackupExchangeManager(
+			SocialBackupExchangeManagerImpl socialBackupExchangeManager) {
 		return socialBackupExchangeManager;
 	}
+
+	@Provides
+	SecretOwnerTask secretOwnerTask(SecretOwnerTaskImpl secretOwnerTask) {
+		return secretOwnerTask;
+	}
+
+	@Provides
+	CustodianTask custodianTask(CustodianTaskImpl custodianTask) {
+		return custodianTask;
+	}
 }

briar-core/src/main/java/org/briarproject/briar/socialbackup/recovery/CustodianTaskImpl.java

@@ -0,0 +1,180 @@
+package org.briarproject.briar.socialbackup.recovery;
+
+import org.briarproject.bramble.api.client.ClientHelper;
+import org.briarproject.bramble.api.crypto.AgreementPublicKey;
+import org.briarproject.bramble.api.crypto.AuthenticatedCipher;
+import org.briarproject.bramble.api.crypto.CryptoComponent;
+import org.briarproject.bramble.api.data.BdfList;
+import org.briarproject.bramble.api.transport.StreamReaderFactory;
+import org.briarproject.bramble.api.transport.StreamWriterFactory;
+import org.briarproject.briar.api.socialbackup.recovery.CustodianTask;
+
+import java.io.DataInputStream;
+import java.io.IOException;
+import java.io.OutputStream;
+import java.net.InetAddress;
+import java.net.InetSocketAddress;
+import java.net.Socket;
+import java.net.SocketTimeoutException;
+import java.nio.ByteBuffer;
+import java.security.GeneralSecurityException;
+import java.util.logging.Logger;
+
+import javax.inject.Inject;
+
+import static java.util.logging.Logger.getLogger;
+
+public class CustodianTaskImpl extends ReturnShardTaskImpl
+		implements CustodianTask {
+
+	private boolean cancelled = false;
+	private Observer observer;
+	private final ClientHelper clientHelper;
+	private InetSocketAddress remoteSocketAddress;
+	private Socket socket;
+	private final AuthenticatedCipher cipher;
+	private byte[] payload;
+//	private final StreamReaderFactory streamReaderFactory;
+//	private final StreamWriterFactory streamWriterFactory;
+
+	private static final Logger LOG =
+			getLogger(CustodianTaskImpl.class.getName());
+
+	@Inject
+	CustodianTaskImpl(CryptoComponent crypto, ClientHelper clientHelper,
+			AuthenticatedCipher cipher, StreamReaderFactory streamReaderFactory,
+			StreamWriterFactory streamWriterFactory) {
+		super(cipher, crypto);
+		this.clientHelper = clientHelper;
+//		this.streamReaderFactory = streamReaderFactory;
+//		this.streamWriterFactory = streamWriterFactory;
+
+		this.cipher = cipher;
+	}
+
+	@Override
+	public void start(Observer observer, byte[] payload) {
+		this.observer = observer;
+		this.payload = payload;
+		observer.onStateChanged(new CustodianTask.State.Connecting());
+	}
+
+	@Override
+	public void cancel() {
+		cancelled = true;
+		if (socket != null) {
+			try {
+				socket.close();
+			} catch (IOException e) {
+				// The reason here is OTHER rather than NO_CONNECTION because
+				// the socket could fail to close because it is already closed
+				observer.onStateChanged(new CustodianTask.State.Failure(
+						State.Failure.Reason.OTHER));
+			}
+		}
+		if (observer != null) {
+			observer.onStateChanged(
+					new CustodianTask.State.Failure(State.Failure.Reason.OTHER));
+		}
+	}
+
+	@Override
+	public void qrCodeDecoded(byte[] qrCodePayloadRaw) {
+		try {
+			BdfList qrCodePayload = clientHelper.toList(qrCodePayloadRaw);
+			AgreementPublicKey remotePublicKey =
+					new AgreementPublicKey(qrCodePayload.getRaw(0));
+			byte[] addressRaw = qrCodePayload.getRaw(1);
+			int port = qrCodePayload.getLong(2).intValue();
+			remoteSocketAddress =
+					new InetSocketAddress(InetAddress.getByAddress(addressRaw),
+							port);
+			deriveSharedSecret(remotePublicKey, addressRaw);
+
+			LOG.info("Qr code payload parsed successfully");
+		} catch (Exception e) {
+			observer.onStateChanged(new CustodianTask.State.Failure(
+					State.Failure.Reason.QR_CODE_INVALID));
+			return;
+		}
+		connectAndSendShard();
+	}
+
+	private void connectAndSendShard() {
+		observer.onStateChanged(new CustodianTask.State.SendingShard());
+		try {
+			LOG.info("Connecting to secret owner " + remoteSocketAddress);
+			socket = new Socket();
+			socket.connect(remoteSocketAddress, TIMEOUT);
+			LOG.info("Connected to secret owner " + remoteSocketAddress);
+
+			OutputStream outputStream = socket.getOutputStream();
+
+			byte[] payloadNonce = generateNonce();
+
+			byte[] payloadEncrypted = encrypt(payload, payloadNonce);
+			outputStream.write(localKeyPair.getPublic().getEncoded());
+			outputStream.write(payloadNonce);
+			outputStream.write(ByteBuffer.allocate(4)
+					.putInt(payloadEncrypted.length)
+					.array());
+			LOG.info("Written payload header");
+
+			outputStream.write(payloadEncrypted);
+
+//			OutputStream encryptedOutputStream = streamWriterFactory
+//					.createContactExchangeStreamWriter(outputStream,
+//							sharedSecret).getOutputStream();
+//			encryptedOutputStream.write(payload);
+
+			LOG.info("Written payload");
+
+			observer.onStateChanged(new CustodianTask.State.ReceivingAck());
+		} catch (IOException e) {
+			if (e instanceof SocketTimeoutException) {
+				LOG.warning("Timed out connecting to secret owner");
+				observer.onStateChanged(new CustodianTask.State.Failure(
+						State.Failure.Reason.NO_CONNECTION));
+				return;
+			}
+			LOG.warning("IO Error connecting to secret owner " + e.getMessage());
+			observer.onStateChanged(new CustodianTask.State.Failure(
+					State.Failure.Reason.QR_CODE_INVALID));
+			return;
+//		}
+		} catch (GeneralSecurityException e) {
+			LOG.warning("Security error "+ e.getMessage());
+			observer.onStateChanged(new CustodianTask.State.Failure(
+					State.Failure.Reason.OTHER));
+			return;
+		}
+		receiveAck();
+	}
+
+	private void receiveAck() {
+		try {
+			DataInputStream inputStream = new DataInputStream(socket.getInputStream());
+//			InputStream inputStream = streamReaderFactory
+//					.createContactExchangeStreamReader(socket.getInputStream(),
+//							sharedSecret);
+			byte[] ackNonce = read(inputStream, NONCE_LENGTH);
+			byte[] ackMessageEncrypted =
+					read(inputStream, 3 + cipher.getMacBytes());
+			byte[] ackMessage = decrypt(ackMessageEncrypted, ackNonce);
+			String ackMessageString = new String(ackMessage);
+			LOG.info("Received ack message: " + new String(ackMessage));
+			if (!ackMessageString.equals("ack"))
+				throw new GeneralSecurityException("Bad ack message");
+			observer.onStateChanged(new CustodianTask.State.Success());
+			socket.close();
+		} catch (IOException e) {
+			LOG.warning("IO Error reading ack " + e.getMessage());
+			observer.onStateChanged(new CustodianTask.State.Failure(
+					State.Failure.Reason.QR_CODE_INVALID));
+		} catch (GeneralSecurityException e) {
+			LOG.warning("Security Error reading ack " + e.getMessage());
+			observer.onStateChanged(new CustodianTask.State.Failure(
+					State.Failure.Reason.OTHER));
+		}
+	}
+}

briar-core/src/main/java/org/briarproject/briar/socialbackup/recovery/ReturnShardTaskImpl.java

@@ -0,0 +1,69 @@
+package org.briarproject.briar.socialbackup.recovery;
+
+import org.briarproject.bramble.api.crypto.AgreementPublicKey;
+import org.briarproject.bramble.api.crypto.AuthenticatedCipher;
+import org.briarproject.bramble.api.crypto.CryptoComponent;
+import org.briarproject.bramble.api.crypto.KeyPair;
+import org.briarproject.bramble.api.crypto.SecretKey;
+
+import java.io.DataInputStream;
+import java.io.IOException;
+import java.io.InputStream;
+import java.security.GeneralSecurityException;
+import java.security.SecureRandom;
+
+public class ReturnShardTaskImpl {
+	private final AuthenticatedCipher cipher;
+	private final CryptoComponent crypto;
+	private final SecureRandom secureRandom;
+	final int PORT = 3002;
+	final int TIMEOUT = 120 * 1000;
+	final int NONCE_LENGTH = 24; // TODO get these constants
+	final int AGREEMENT_PUBLIC_KEY_LENGTH = 32;
+	SecretKey sharedSecret;
+	final KeyPair localKeyPair;
+
+	ReturnShardTaskImpl(AuthenticatedCipher cipher, CryptoComponent crypto) {
+		this.cipher = cipher;
+		this.crypto = crypto;
+		this.secureRandom = crypto.getSecureRandom();
+		localKeyPair = crypto.generateAgreementKeyPair();
+	}
+
+	byte[] generateNonce() {
+		byte[] nonce = new byte[NONCE_LENGTH];
+		secureRandom.nextBytes(nonce);
+		return nonce;
+	}
+
+	void deriveSharedSecret(AgreementPublicKey remotePublicKey, byte[] context)
+			throws
+			GeneralSecurityException {
+		sharedSecret =
+				crypto.deriveSharedSecret("ShardReturn", remotePublicKey,
+						localKeyPair, context);
+	}
+
+	byte[] encrypt(byte[] message, byte[] nonce)
+			throws GeneralSecurityException {
+		cipher.init(true, sharedSecret, nonce);
+		byte[] cipherText = new byte[message.length + cipher.getMacBytes()];
+		cipher.process(message, 0, message.length, cipherText, 0);
+		return cipherText;
+	}
+
+	byte[] decrypt(byte[] cipherText, byte[] nonce)
+			throws GeneralSecurityException {
+		cipher.init(false, sharedSecret, nonce);
+		byte[] message = new byte[cipherText.length - cipher.getMacBytes()];
+		cipher.process(cipherText, 0, cipherText.length, message, 0);
+		return message;
+	}
+
+	byte[] read(DataInputStream dis, int length)
+			throws IOException {
+		byte[] output = new byte[length];
+		dis.readFully(output);
+		return output;
+	}
+}

briar-core/src/main/java/org/briarproject/briar/socialbackup/recovery/SecretOwnerTaskImpl.java

@@ -0,0 +1,186 @@
+package org.briarproject.briar.socialbackup.recovery;
+
+import org.briarproject.bramble.api.FormatException;
+import org.briarproject.bramble.api.client.ClientHelper;
+import org.briarproject.bramble.api.crypto.AgreementPublicKey;
+import org.briarproject.bramble.api.crypto.AuthenticatedCipher;
+import org.briarproject.bramble.api.crypto.CryptoComponent;
+import org.briarproject.bramble.api.data.BdfList;
+import org.briarproject.briar.api.socialbackup.MessageParser;
+import org.briarproject.briar.api.socialbackup.ReturnShardPayload;
+import org.briarproject.briar.api.socialbackup.recovery.SecretOwnerTask;
+
+import java.io.DataInputStream;
+import java.io.DataOutputStream;
+import java.io.IOException;
+import java.net.InetAddress;
+import java.net.InetSocketAddress;
+import java.net.ServerSocket;
+import java.net.Socket;
+import java.nio.ByteBuffer;
+import java.security.GeneralSecurityException;
+import java.util.logging.Logger;
+
+import javax.inject.Inject;
+
+import static java.util.logging.Logger.getLogger;
+
+public class SecretOwnerTaskImpl extends ReturnShardTaskImpl
+		implements SecretOwnerTask {
+
+	private boolean cancelled = false;
+	private InetSocketAddress socketAddress;
+	private ClientHelper clientHelper;
+	private Observer observer;
+	private ServerSocket serverSocket;
+	private Socket socket;
+	private MessageParser messageParser;
+
+//	private final StreamReaderFactory streamReaderFactory;
+//  private final StreamWriterFactory streamWriterFactory;
+
+	private static final Logger LOG =
+			getLogger(SecretOwnerTaskImpl.class.getName());
+
+	@Inject
+	SecretOwnerTaskImpl(AuthenticatedCipher cipher, CryptoComponent crypto,
+			ClientHelper clientHelper) {
+		super(cipher, crypto);
+		this.clientHelper = clientHelper;
+//		this.streamReaderFactory = streamReaderFactory;
+//		this.streamWriterFactory = streamWriterFactory;
+	}
+
+	@Override
+	public void start(Observer observer, InetAddress inetAddress) {
+		this.observer = observer;
+		if (inetAddress == null) {
+			LOG.warning("Cannot retrieve local IP address, failing.");
+			observer.onStateChanged(
+					new State.Failure(State.Failure.Reason.NO_CONNECTION));
+		}
+		LOG.info("InetAddress is " + inetAddress);
+		socketAddress = new InetSocketAddress(inetAddress, PORT);
+
+		// If we have a socket already open, close it and start fresh
+		if (serverSocket != null) {
+			try {
+				serverSocket.close();
+			} catch (IOException ignored) {}
+		}
+
+		// Start listening on socketAddress
+		try {
+			LOG.info("Binding socket");
+			serverSocket = new ServerSocket();
+			serverSocket.bind(socketAddress);
+			LOG.info("Binding socket done");
+		} catch (IOException e) {
+			LOG.warning(
+					"IO Error when listening on local socket" + e.getMessage());
+			observer.onStateChanged(
+					new State.Failure(State.Failure.Reason.NO_CONNECTION));
+			// TODO could try incrementing the port number
+			return;
+		}
+
+		try {
+			// TODO add version number
+			BdfList payloadList = new BdfList();
+			payloadList.add(localKeyPair.getPublic().getEncoded());
+			payloadList.add(socketAddress.getAddress().getAddress());
+			payloadList.add(socketAddress.getPort());
+			observer.onStateChanged(
+					new State.Listening(clientHelper.toByteArray(payloadList)));
+		} catch (FormatException e) {
+			LOG.warning("Error encoding QR code");
+			observer.onStateChanged(
+					new State.Failure(State.Failure.Reason.OTHER));
+			return;
+		}
+		LOG.info("Receiving payload");
+		receivePayload();
+	}
+
+	private void receivePayload() {
+		try {
+			LOG.info("Waiting for a connection...");
+			socket = serverSocket.accept();
+			LOG.info("Client connected");
+			observer.onStateChanged(new State.ReceivingShard());
+
+			DataInputStream inputStream =
+					new DataInputStream(socket.getInputStream());
+
+			AgreementPublicKey remotePublicKey =
+					new AgreementPublicKey(
+							read(inputStream, AGREEMENT_PUBLIC_KEY_LENGTH));
+			LOG.info("Read remote public key");
+
+			byte[] addressRaw = socketAddress.getAddress().getAddress();
+			deriveSharedSecret(remotePublicKey, addressRaw);
+
+			byte[] payloadNonce = read(inputStream, NONCE_LENGTH);
+			LOG.info("Read payload nonce");
+
+			byte[] payloadLengthRaw = read(inputStream, 4);
+			int payloadLength = ByteBuffer.wrap(payloadLengthRaw).getInt();
+			LOG.info("Expected payload length " + payloadLength + " bytes");
+
+			byte[] payloadRaw = read(inputStream, payloadLength);
+
+//		    InputStream clearInputStream = streamReaderFactory.createContactExchangeStreamReader(inputStream, sharedSecret);
+
+//		    byte[] payloadClear = read(clearInputStream, payloadLength);
+			byte[] payloadClear = decrypt(payloadRaw, payloadNonce);
+			ReturnShardPayload returnShardPayload = ReturnShardPayload
+					.fromList(clientHelper.toList(payloadClear));
+
+			LOG.info("Payload decrypted and parsed successfully");
+
+//			StreamWriter streamWriter = streamWriterFactory.createContactExchangeStreamWriter(socket.getOutputStream(), sharedSecret);
+//			OutputStream outputStream = streamWriter.getOutputStream();
+
+			DataOutputStream outputStream =
+					new DataOutputStream(socket.getOutputStream());
+			byte[] ackNonce = generateNonce();
+			outputStream.write(ackNonce);
+
+			byte[] ackMessage = encrypt("ack".getBytes(), ackNonce);
+			outputStream.write(ackMessage);
+			LOG.info("Acknowledgement sent");
+
+			serverSocket.close();
+
+			observer.onStateChanged(new State.Success(returnShardPayload));
+		} catch (IOException e) {
+			LOG.warning("IO Error receiving payload " + e.getMessage());
+			// TODO reasons
+			observer.onStateChanged(
+					new State.Failure(State.Failure.Reason.NO_CONNECTION));
+		} catch (GeneralSecurityException e) {
+			LOG.warning("Security Error receiving payload " + e.getMessage());
+			observer.onStateChanged(
+					new State.Failure(State.Failure.Reason.SECURITY));
+		}
+	}
+
+	@Override
+	public void cancel() {
+		cancelled = true;
+		LOG.info("Cancel called, failing...");
+		if (serverSocket != null) {
+			try {
+				serverSocket.close();
+			} catch (IOException e) {
+				observer.onStateChanged(
+						new State.Failure(State.Failure.Reason.OTHER));
+			}
+		}
+
+		if (observer != null) {
+			observer.onStateChanged(
+					new State.Failure(State.Failure.Reason.OTHER));
+		}
+	}
+}

briar-core/src/test/java/org/briarproject/briar/socialbackup/recovery/ReturnShardIntegrationTest.java

@@ -0,0 +1,150 @@
+package org.briarproject.briar.socialbackup.recovery;
+
+import org.briarproject.bramble.BrambleCoreIntegrationTestEagerSingletons;
+import org.briarproject.bramble.api.lifecycle.LifecycleManager;
+import org.briarproject.bramble.test.BrambleTestCase;
+import org.briarproject.bramble.test.TestDatabaseConfigModule;
+import org.briarproject.briar.api.socialbackup.BackupPayload;
+import org.briarproject.briar.api.socialbackup.ReturnShardPayload;
+import org.briarproject.briar.api.socialbackup.Shard;
+import org.briarproject.briar.api.socialbackup.recovery.CustodianTask;
+import org.briarproject.briar.api.socialbackup.recovery.SecretOwnerTask;
+import org.junit.After;
+import org.junit.Before;
+import org.junit.Test;
+
+import java.io.File;
+import java.net.InetAddress;
+import java.util.Arrays;
+import java.util.concurrent.Executor;
+
+import static junit.framework.TestCase.fail;
+import static org.briarproject.bramble.test.TestUtils.deleteTestDirectory;
+import static org.briarproject.bramble.test.TestUtils.getTestDirectory;
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertTrue;
+
+public class ReturnShardIntegrationTest extends BrambleTestCase {
+
+	private final File testDir = getTestDirectory();
+	private final File ownerDir = new File(testDir, "owner");
+	private final File custodianDir = new File(testDir, "custodian");
+
+	private ReturnShardIntegrationTestComponent owner, custodian;
+
+	@Before
+	public void setUp() throws Exception {
+		assertTrue(testDir.mkdirs());
+		// Create the devices
+		owner = DaggerReturnShardIntegrationTestComponent.builder()
+				.testDatabaseConfigModule(
+						new TestDatabaseConfigModule(ownerDir)).build();
+		BrambleCoreIntegrationTestEagerSingletons.Helper
+				.injectEagerSingletons(owner);
+		custodian = DaggerReturnShardIntegrationTestComponent.builder()
+				.testDatabaseConfigModule(new TestDatabaseConfigModule(
+						custodianDir))
+				.build();
+		BrambleCoreIntegrationTestEagerSingletons.Helper
+				.injectEagerSingletons(custodian);
+	}
+
+	@Test
+	public void testReturnShard() {
+		SecretOwnerTask secretOwnerTask = owner.getSecretOwnerTask();
+		CustodianTask custodianTask = custodian.getCustodianTask();
+		byte[] payload = "its nice to be important but its more important to be nice".getBytes();
+
+		Shard shard = new Shard("secretid".getBytes(), "shard".getBytes());
+		BackupPayload backupPayload = new BackupPayload("backup payload".getBytes());
+        ReturnShardPayload returnShardPayload = new ReturnShardPayload(shard, backupPayload);
+
+//        payloadBytes = clientHelper
+
+		SecretOwnerTask.Observer ownerObserver =
+				state -> {
+					if (state instanceof SecretOwnerTask.State.Listening) {
+						SecretOwnerTask.State.Listening listening =
+								(SecretOwnerTask.State.Listening) state;
+						byte[] qrPayload = listening.getLocalPayload();
+						System.out.println(qrPayload.length);
+						transferQrCode(custodianTask, qrPayload);
+					} else if (state instanceof SecretOwnerTask.State.Success) {
+						ReturnShardPayload remotePayload = ((SecretOwnerTask.State.Success) state).getRemotePayload();
+						assertTrue(remotePayload.equals(payload));
+						System.out.println("Success");
+					} else if (state instanceof SecretOwnerTask.State.Failure) {
+						System.out.println("Owner state: failure");
+						fail();
+					} else {
+						System.out.println(
+								"owner: " + state.getClass().getSimpleName());
+					}
+				};
+
+		CustodianTask.Observer custodianObserver =
+				state -> {
+					if (state instanceof CustodianTask.State.Success) {
+						assertEquals(1, 1);
+					} else if (state instanceof CustodianTask.State.Failure) {
+						fail();
+					} else {
+						System.out.println(
+								"custodian: " + state.getClass().getSimpleName());
+					}
+				};
+
+		owner.getIoExecutor().execute(() -> {
+			try {
+				secretOwnerTask
+						.start(ownerObserver, InetAddress.getLocalHost());
+			} catch (Exception e) {
+				fail();
+			}
+		});
+
+		custodian.getIoExecutor().execute(() -> {
+			try {
+				custodianTask.start(custodianObserver, payload);
+			} catch (Exception e) {
+				fail();
+			}
+		});
+
+		// TODO how to get the test to wait for the io to finish
+		try {
+//			Thread.sleep(1000);
+			tearDown();
+		} catch (Exception e) {
+			fail();
+		}
+
+	}
+
+	private void transferQrCode(CustodianTask custodianTask, byte[] payload) {
+		custodian.getIoExecutor().execute(() -> {
+			try {
+				custodianTask.qrCodeDecoded(payload);
+			} catch (Exception e) {
+				e.printStackTrace();
+				fail();
+			}
+		});
+	}
+
+	private void tearDown(ReturnShardIntegrationTestComponent device)
+			throws Exception {
+		// Stop the lifecycle manager
+		LifecycleManager lifecycleManager = device.getLifecycleManager();
+		lifecycleManager.stopServices();
+		lifecycleManager.waitForShutdown();
+	}
+
+	@After
+	public void tearDown() throws Exception {
+		tearDown(owner);
+		tearDown(custodian);
+		deleteTestDirectory(testDir);
+	}
+
+}

briar-core/src/test/java/org/briarproject/briar/socialbackup/recovery/ReturnShardIntegrationTestComponent.java

@@ -0,0 +1,50 @@
+package org.briarproject.briar.socialbackup.recovery;
+
+import org.briarproject.bramble.BrambleCoreIntegrationTestEagerSingletons;
+import org.briarproject.bramble.BrambleCoreModule;
+import org.briarproject.bramble.api.connection.ConnectionManager;
+import org.briarproject.bramble.api.contact.ContactExchangeManager;
+import org.briarproject.bramble.api.contact.ContactManager;
+import org.briarproject.bramble.api.event.EventBus;
+import org.briarproject.bramble.api.identity.IdentityManager;
+import org.briarproject.bramble.api.lifecycle.IoExecutor;
+import org.briarproject.bramble.api.lifecycle.LifecycleManager;
+import org.briarproject.bramble.test.BrambleCoreIntegrationTestModule;
+import org.briarproject.briar.api.socialbackup.recovery.CustodianTask;
+import org.briarproject.briar.api.socialbackup.recovery.SecretOwnerTask;
+import org.briarproject.briar.socialbackup.SocialBackupModule;
+
+import java.util.concurrent.Executor;
+
+import javax.inject.Singleton;
+
+import dagger.Component;
+
+@Singleton
+@Component(modules = {
+		BrambleCoreIntegrationTestModule.class,
+		BrambleCoreModule.class,
+		SocialBackupModule.class
+})
+interface ReturnShardIntegrationTestComponent
+		extends BrambleCoreIntegrationTestEagerSingletons {
+
+	ConnectionManager getConnectionManager();
+
+	ContactExchangeManager getContactExchangeManager();
+
+	ContactManager getContactManager();
+
+	EventBus getEventBus();
+
+	IdentityManager getIdentityManager();
+
+	@IoExecutor
+	Executor getIoExecutor();
+
+	LifecycleManager getLifecycleManager();
+
+	SecretOwnerTask getSecretOwnerTask();
+
+	CustodianTask getCustodianTask();
+}