Fixes FS#147: Disable OMEMO

src/main/java/de/thedevstack/conversationsplus/ConversationsPlusPreferences.java

@@ -14,6 +14,10 @@ public class ConversationsPlusPreferences extends Settings {
     private static ConversationsPlusPreferences instance;
     private final SharedPreferences sharedPreferences;
 
+    public static boolean omemoEnabled() {
+        return getBoolean("omemo_enabled", false);
+    }
+
     public static String imgTransferFolder() {
         return getString("img_transfer_folder", getString("app_name", "Conversations+"));
     }

src/main/java/eu/siacs/conversations/Config.java

@@ -2,6 +2,7 @@ package eu.siacs.conversations;
 
 import android.graphics.Bitmap;
 
+import de.thedevstack.conversationsplus.ConversationsPlusPreferences;
 import eu.siacs.conversations.xmpp.chatstate.ChatState;
 
 public final class Config {
@@ -31,7 +32,7 @@ public final class Config {
 	}
 
 	public static boolean supportOmemo() {
-		return (ENCRYPTION_MASK & OMEMO) != 0;
+		return ConversationsPlusPreferences.omemoEnabled();
 	}
 
 	public static boolean multipleEncryptionChoices() {

src/main/java/eu/siacs/conversations/crypto/axolotl/AxolotlServiceStub.java

@@ -0,0 +1,196 @@
+package eu.siacs.conversations.crypto.axolotl;
+
+import android.support.annotation.NonNull;
+import android.support.annotation.Nullable;
+
+import org.whispersystems.libaxolotl.AxolotlAddress;
+import org.whispersystems.libaxolotl.IdentityKey;
+import org.whispersystems.libaxolotl.state.PreKeyRecord;
+import org.whispersystems.libaxolotl.state.SignedPreKeyRecord;
+
+import java.security.cert.X509Certificate;
+import java.util.Collections;
+import java.util.Set;
+
+import eu.siacs.conversations.entities.Account;
+import eu.siacs.conversations.entities.Contact;
+import eu.siacs.conversations.entities.Conversation;
+import eu.siacs.conversations.entities.Message;
+import eu.siacs.conversations.xmpp.jid.Jid;
+
+/**
+ * Axolotl Service Stub implementation to avoid axolotl usage.
+ */
+public class AxolotlServiceStub implements AxolotlService {
+
+    @Override
+    public boolean fetchMapHasErrors(Contact contact) {
+        return false;
+    }
+
+    @Override
+    public String getOwnFingerprint() {
+        return null;
+    }
+
+    @Override
+    public Set<IdentityKey> getKeysWithTrust(XmppAxolotlSession.Trust trust) {
+        return Collections.emptySet();
+    }
+
+    @Override
+    public Set<IdentityKey> getKeysWithTrust(XmppAxolotlSession.Trust trust, Contact contact) {
+        return Collections.emptySet();
+    }
+
+    @Override
+    public long getNumTrustedKeys(Contact contact) {
+        return 0;
+    }
+
+    @Override
+    public Set<String> getFingerprintsForOwnSessions() {
+        return Collections.emptySet();
+    }
+
+    @Override
+    public Set<String> getFingerprintsForContact(Contact contact) {
+        return Collections.emptySet();
+    }
+
+    @Override
+    public boolean isPepBroken() {
+        return true;
+    }
+
+    @Override
+    public void regenerateKeys(boolean wipeOther) {
+
+    }
+
+    @Override
+    public int getOwnDeviceId() {
+        return 0;
+    }
+
+    @Override
+    public Set<Integer> getOwnDeviceIds() {
+        return Collections.emptySet();
+    }
+
+    @Override
+    public void registerDevices(Jid jid, @NonNull Set<Integer> deviceIds) {
+
+    }
+
+    @Override
+    public void wipeOtherPepDevices() {
+
+    }
+
+    @Override
+    public void purgeKey(String fingerprint) {
+
+    }
+
+    @Override
+    public void publishOwnDeviceIdIfNeeded() {
+
+    }
+
+    @Override
+    public void publishOwnDeviceId(Set<Integer> deviceIds) {
+
+    }
+
+    @Override
+    public void publishDeviceVerificationAndBundle(SignedPreKeyRecord signedPreKeyRecord, Set<PreKeyRecord> preKeyRecords, boolean announceAfter, boolean wipe) {
+
+    }
+
+    @Override
+    public void publishBundlesIfNeeded(boolean announce, boolean wipe) {
+
+    }
+
+    @Override
+    public boolean isContactAxolotlCapable(Contact contact) {
+        return false;
+    }
+
+    @Override
+    public XmppAxolotlSession.Trust getFingerprintTrust(String fingerprint) {
+        return XmppAxolotlSession.Trust.TRUSTED;
+    }
+
+    @Override
+    public X509Certificate getFingerprintCertificate(String fingerprint) {
+        return null;
+    }
+
+    @Override
+    public void setFingerprintTrust(String fingerprint, XmppAxolotlSession.Trust trust) {
+
+    }
+
+    @Override
+    public Set<AxolotlAddress> findDevicesWithoutSession(Conversation conversation) {
+        return Collections.emptySet();
+    }
+
+    @Override
+    public Set<AxolotlAddress> findDevicesWithoutSession(Jid contactJid) {
+        return Collections.emptySet();
+    }
+
+    @Override
+    public boolean createSessionsIfNeeded(Conversation conversation) {
+        return false;
+    }
+
+    @Override
+    public boolean trustedSessionVerified(Conversation conversation) {
+        return false;
+    }
+
+    @Override
+    public boolean hasPendingKeyFetches(Account account, Contact contact) {
+        return false;
+    }
+
+    @Nullable
+    @Override
+    public XmppAxolotlMessage encrypt(Message message) {
+        return null;
+    }
+
+    @Override
+    public void preparePayloadMessage(Message message, boolean delay) {
+
+    }
+
+    @Override
+    public void prepareKeyTransportMessage(Contact contact, OnMessageCreatedCallback onMessageCreatedCallback) {
+
+    }
+
+    @Override
+    public XmppAxolotlMessage fetchAxolotlMessageFromCache(Message message) {
+        return null;
+    }
+
+    @Override
+    public XmppAxolotlMessage.XmppAxolotlPlaintextMessage processReceivingPayloadMessage(XmppAxolotlMessage message) {
+        return null;
+    }
+
+    @Override
+    public XmppAxolotlMessage.XmppAxolotlKeyTransportMessage processReceivingKeyTransportMessage(XmppAxolotlMessage message) {
+        return null;
+    }
+
+    @Override
+    public void onAdvancedStreamFeaturesAvailable(Account account) {
+
+    }
+}

src/main/java/eu/siacs/conversations/crypto/axolotl/SQLiteAxolotlStore.java

@@ -77,7 +77,7 @@ public class SQLiteAxolotlStore implements AxolotlStore {
 		this.localRegistrationId = loadRegistrationId();
 		this.currentPreKeyId = loadCurrentPreKeyId();
 		for (SignedPreKeyRecord record : loadSignedPreKeys()) {
-			Log.d(Config.LOGTAG, AxolotlService.getLogprefix(account) + "Got Axolotl signed prekey record:" + record.getId());
+			Log.d(Config.LOGTAG, AxolotlServiceImpl.getLogprefix(account) + "Got Axolotl signed prekey record:" + record.getId());
 		}
 	}
 
@@ -95,7 +95,7 @@ public class SQLiteAxolotlStore implements AxolotlStore {
 		if (ownKey != null) {
 			return ownKey;
 		} else {
-			Log.i(Config.LOGTAG, AxolotlService.getLogprefix(account) + "Could not retrieve own IdentityKeyPair");
+			Log.i(Config.LOGTAG, AxolotlServiceImpl.getLogprefix(account) + "Could not retrieve own IdentityKeyPair");
 			ownKey = generateIdentityKeyPair();
 			mXmppConnectionService.databaseBackend.storeOwnIdentityKeyPair(account, ownKey);
 		}
@@ -112,13 +112,13 @@ public class SQLiteAxolotlStore implements AxolotlStore {
 		if (!regenerate && regIdString != null) {
 			reg_id = Integer.valueOf(regIdString);
 		} else {
-			Log.i(Config.LOGTAG, AxolotlService.getLogprefix(account) + "Could not retrieve axolotl registration id for account " + account.getJid());
+			Log.i(Config.LOGTAG, AxolotlServiceImpl.getLogprefix(account) + "Could not retrieve axolotl registration id for account " + account.getJid());
 			reg_id = generateRegistrationId();
 			boolean success = this.account.setKey(JSONKEY_REGISTRATION_ID, Integer.toString(reg_id));
 			if (success) {
 				mXmppConnectionService.databaseBackend.updateAccount(account);
 			} else {
-				Log.e(Config.LOGTAG, AxolotlService.getLogprefix(account) + "Failed to write new key to the database!");
+				Log.e(Config.LOGTAG, AxolotlServiceImpl.getLogprefix(account) + "Failed to write new key to the database!");
 			}
 		}
 		return reg_id;
@@ -130,7 +130,7 @@ public class SQLiteAxolotlStore implements AxolotlStore {
 		if (regIdString != null) {
 			reg_id = Integer.valueOf(regIdString);
 		} else {
-			Log.w(Config.LOGTAG, AxolotlService.getLogprefix(account) + "Could not retrieve current prekey id for account " + account.getJid());
+			Log.w(Config.LOGTAG, AxolotlServiceImpl.getLogprefix(account) + "Could not retrieve current prekey id for account " + account.getJid());
 			reg_id = 0;
 		}
 		return reg_id;
@@ -344,7 +344,7 @@ public class SQLiteAxolotlStore implements AxolotlStore {
 		if (success) {
 			mXmppConnectionService.databaseBackend.updateAccount(account);
 		} else {
-			Log.e(Config.LOGTAG, AxolotlService.getLogprefix(account) + "Failed to write new prekey id to the database!");
+			Log.e(Config.LOGTAG, AxolotlServiceImpl.getLogprefix(account) + "Failed to write new prekey id to the database!");
 		}
 	}
 

src/main/java/eu/siacs/conversations/crypto/axolotl/XmppAxolotlSession.java

@@ -168,10 +168,10 @@ public class XmppAxolotlSession {
 				try {
 					try {
 						PreKeyWhisperMessage message = new PreKeyWhisperMessage(encryptedKey);
-						Log.i(Config.LOGTAG, AxolotlService.getLogprefix(account) + "PreKeyWhisperMessage received, new session ID:" + message.getSignedPreKeyId() + "/" + message.getPreKeyId());
+						Log.i(Config.LOGTAG, AxolotlServiceImpl.getLogprefix(account) + "PreKeyWhisperMessage received, new session ID:" + message.getSignedPreKeyId() + "/" + message.getPreKeyId());
 						IdentityKey msgIdentityKey = message.getIdentityKey();
 						if (this.identityKey != null && !this.identityKey.equals(msgIdentityKey)) {
-							Log.e(Config.LOGTAG, AxolotlService.getLogprefix(account) + "Had session with fingerprint " + this.getFingerprint() + ", received message with fingerprint " + msgIdentityKey.getFingerprint());
+							Log.e(Config.LOGTAG, AxolotlServiceImpl.getLogprefix(account) + "Had session with fingerprint " + this.getFingerprint() + ", received message with fingerprint " + msgIdentityKey.getFingerprint());
 						} else {
 							this.identityKey = msgIdentityKey;
 							plaintext = cipher.decrypt(message);
@@ -180,14 +180,14 @@ public class XmppAxolotlSession {
 							}
 						}
 					} catch (InvalidMessageException | InvalidVersionException e) {
-						Log.i(Config.LOGTAG, AxolotlService.getLogprefix(account) + "WhisperMessage received");
+						Log.i(Config.LOGTAG, AxolotlServiceImpl.getLogprefix(account) + "WhisperMessage received");
 						WhisperMessage message = new WhisperMessage(encryptedKey);
 						plaintext = cipher.decrypt(message);
 					} catch (InvalidKeyException | InvalidKeyIdException | UntrustedIdentityException e) {
-						Log.w(Config.LOGTAG, AxolotlService.getLogprefix(account) + "Error decrypting axolotl header, " + e.getClass().getName() + ": " + e.getMessage());
+						Log.w(Config.LOGTAG, AxolotlServiceImpl.getLogprefix(account) + "Error decrypting axolotl header, " + e.getClass().getName() + ": " + e.getMessage());
 					}
 				} catch (LegacyMessageException | InvalidMessageException | DuplicateMessageException | NoSessionException e) {
-					Log.w(Config.LOGTAG, AxolotlService.getLogprefix(account) + "Error decrypting axolotl header, " + e.getClass().getName() + ": " + e.getMessage());
+					Log.w(Config.LOGTAG, AxolotlServiceImpl.getLogprefix(account) + "Error decrypting axolotl header, " + e.getClass().getName() + ": " + e.getMessage());
 				}
 
 				if (plaintext != null) {

src/main/java/eu/siacs/conversations/entities/Account.java

@@ -19,11 +19,14 @@ import java.util.List;
 import java.util.concurrent.CopyOnWriteArrayList;
 import java.util.concurrent.CopyOnWriteArraySet;
 
+import de.thedevstack.conversationsplus.ConversationsPlusPreferences;
 import eu.siacs.conversations.Config;
 import eu.siacs.conversations.R;
 import eu.siacs.conversations.crypto.OtrService;
 import eu.siacs.conversations.crypto.PgpDecryptionService;
 import eu.siacs.conversations.crypto.axolotl.AxolotlService;
+import eu.siacs.conversations.crypto.axolotl.AxolotlServiceImpl;
+import eu.siacs.conversations.crypto.axolotl.AxolotlServiceStub;
 import eu.siacs.conversations.services.XmppConnectionService;
 import eu.siacs.conversations.xmpp.XmppConnection;
 import eu.siacs.conversations.xmpp.jid.InvalidJidException;
@@ -352,10 +355,15 @@ public class Account extends AbstractEntity {
 
 	public void initAccountServices(final XmppConnectionService context) {
 		this.mOtrService = new OtrService(context, this);
-		this.axolotlService = new AxolotlService(this, context);
+        if (ConversationsPlusPreferences.omemoEnabled()) {
-		if (xmppConnection != null) {
+            this.axolotlService = new AxolotlServiceImpl(this, context);
-			xmppConnection.addOnAdvancedStreamFeaturesAvailableListener(axolotlService);
+            if (xmppConnection != null) {
-		}
+                xmppConnection.addOnAdvancedStreamFeaturesAvailableListener(axolotlService);
+            }
+        } else {
+            this.axolotlService = new AxolotlServiceStub();
+        }
+
 		this.pgpDecryptionService = new PgpDecryptionService(context);
 	}
 

src/main/java/eu/siacs/conversations/generator/AbstractGenerator.java

@@ -13,13 +13,8 @@ import java.util.Locale;
 import java.util.TimeZone;
 
 import de.thedevstack.conversationsplus.ConversationsPlusApplication;
-import de.thedevstack.conversationsplus.ConversationsPlusPreferences;
 import de.tzur.conversations.Settings;
 import eu.siacs.conversations.crypto.axolotl.AxolotlService;
-import eu.siacs.conversations.services.XmppConnectionService;
-import eu.siacs.conversations.utils.PhoneHelper;
-import eu.siacs.conversations.xmpp.jid.Jid;
-import eu.siacs.conversations.xmpp.stanzas.IqPacket;
 
 public abstract class AbstractGenerator {
 	private final String[] FEATURES = {

src/main/java/eu/siacs/conversations/generator/IqGenerator.java

@@ -25,7 +25,6 @@ import eu.siacs.conversations.services.MessageArchiveService;
 import eu.siacs.conversations.utils.Xmlns;
 import eu.siacs.conversations.xml.Element;
 import eu.siacs.conversations.xmpp.forms.Data;
-import eu.siacs.conversations.xmpp.forms.Field;
 import eu.siacs.conversations.xmpp.jid.Jid;
 import eu.siacs.conversations.xmpp.pep.Avatar;
 import eu.siacs.conversations.xmpp.stanzas.IqPacket;

src/main/java/eu/siacs/conversations/parser/IqParser.java

@@ -157,7 +157,7 @@ public class IqParser extends AbstractParser implements OnIqPacketReceived {
 		try {
 			return Base64.decode(signedPreKeySignature.getContent(), Base64.DEFAULT);
 		} catch (Throwable e) {
-			Log.e(Config.LOGTAG,AxolotlService.LOGPREFIX+" : Invalid base64 in signedPreKeySignature");
+			Log.e(Config.LOGTAG, AxolotlService.LOGPREFIX+" : Invalid base64 in signedPreKeySignature");
 			return null;
 		}
 	}
@@ -171,7 +171,7 @@ public class IqParser extends AbstractParser implements OnIqPacketReceived {
 		try {
 			identityKey = new IdentityKey(Base64.decode(identityKeyElement.getContent(), Base64.DEFAULT), 0);
 		} catch (Throwable e) {
-			Log.e(Config.LOGTAG,AxolotlService.LOGPREFIX+" : "+"Invalid identityKey in PEP: "+e.getMessage());
+			Log.e(Config.LOGTAG, AxolotlService.LOGPREFIX+" : "+"Invalid identityKey in PEP: "+e.getMessage());
 		}
 		return identityKey;
 	}
@@ -211,7 +211,7 @@ public class IqParser extends AbstractParser implements OnIqPacketReceived {
 
 	public Pair<X509Certificate[],byte[]> verification(final IqPacket packet) {
 		Element item = getItem(packet);
-		Element verification = item != null ? item.findChild("verification",AxolotlService.PEP_PREFIX) : null;
+		Element verification = item != null ? item.findChild("verification", AxolotlService.PEP_PREFIX) : null;
 		Element chain = verification != null ? verification.findChild("chain") : null;
 		Element signature = verification != null ? verification.findChild("signature") : null;
 		if (chain != null && signature != null) {

src/main/java/eu/siacs/conversations/parser/MessageParser.java

@@ -10,14 +10,14 @@ import net.java.otr4j.session.SessionStatus;
 
 import java.util.ArrayList;
 import java.util.Set;
-import java.util.UUID;
 
 import de.thedevstack.android.logcat.Logging;
 import de.thedevstack.conversationsplus.ConversationsPlusPreferences;
 import de.thedevstack.conversationsplus.utils.AvatarUtil;
 import eu.siacs.conversations.Config;
-import eu.siacs.conversations.crypto.PgpDecryptionService;
 import eu.siacs.conversations.crypto.axolotl.AxolotlService;
+import eu.siacs.conversations.crypto.axolotl.AxolotlService;
+import eu.siacs.conversations.crypto.axolotl.AxolotlServiceImpl;
 import eu.siacs.conversations.crypto.axolotl.XmppAxolotlMessage;
 import eu.siacs.conversations.entities.Account;
 import eu.siacs.conversations.entities.Bookmark;
@@ -118,7 +118,7 @@ public class MessageParser extends AbstractParser implements
 		if(plaintextMessage != null) {
 			finishedMessage = new Message(conversation, plaintextMessage.getPlaintext(), Message.ENCRYPTION_AXOLOTL, status);
 			finishedMessage.setAxolotlFingerprint(plaintextMessage.getFingerprint());
-			Log.d(Config.LOGTAG, AxolotlService.getLogprefix(finishedMessage.getConversation().getAccount())+" Received Message with session fingerprint: "+plaintextMessage.getFingerprint());
+			Log.d(Config.LOGTAG, AxolotlServiceImpl.getLogprefix(finishedMessage.getConversation().getAccount())+" Received Message with session fingerprint: "+plaintextMessage.getFingerprint());
 		}
 
 		return finishedMessage;
@@ -211,8 +211,8 @@ public class MessageParser extends AbstractParser implements
 				mXmppConnectionService.updateConversationUi();
 				mXmppConnectionService.updateAccountUi();
 			}
-		} else if (AxolotlService.PEP_DEVICE_LIST.equals(node)) {
+		} else if (ConversationsPlusPreferences.omemoEnabled() && AxolotlService.PEP_DEVICE_LIST.equals(node)) {
-			Log.d(Config.LOGTAG, AxolotlService.getLogprefix(account)+"Received PEP device list update from "+ from + ", processing...");
+			Log.d(Config.LOGTAG, AxolotlServiceImpl.getLogprefix(account)+"Received PEP device list update from "+ from + ", processing...");
 			Element item = items.findChild("item");
 			Set<Integer> deviceIds = mXmppConnectionService.getIqParser().deviceIds(item);
 			AxolotlService axolotlService = account.getAxolotlService();
@@ -297,8 +297,6 @@ public class MessageParser extends AbstractParser implements
 		final String body = packet.getBody();
 		final Element mucUserElement = packet.findChild("x", "http://jabber.org/protocol/muc#user");
 		final String pgpEncrypted = packet.findChildContent("x", "jabber:x:encrypted");
-		final Element replaceElement = packet.findChild("replace","urn:xmpp:message-correct:0");
-		final String replacementId = replaceElement == null ? null : replaceElement.getAttribute("id");
 		final Element axolotlEncrypted = packet.findChild(XmppAxolotlMessage.CONTAINERTAG, AxolotlService.PEP_PREFIX);
 		int status;
 		final Jid counterpart;

src/main/java/eu/siacs/conversations/persistance/DatabaseBackend.java

@@ -35,7 +35,7 @@ import org.json.JSONException;
 
 import de.thedevstack.android.logcat.Logging;
 import eu.siacs.conversations.Config;
-import eu.siacs.conversations.crypto.axolotl.AxolotlService;
+import eu.siacs.conversations.crypto.axolotl.AxolotlServiceImpl;
 import eu.siacs.conversations.crypto.axolotl.SQLiteAxolotlStore;
 import eu.siacs.conversations.crypto.axolotl.XmppAxolotlSession;
 import eu.siacs.conversations.entities.Account;
@@ -940,7 +940,7 @@ public class DatabaseBackend extends SQLiteOpenHelper {
 			try {
 				identityKeyPair = new IdentityKeyPair(Base64.decode(cursor.getString(cursor.getColumnIndex(SQLiteAxolotlStore.KEY)), Base64.DEFAULT));
 			} catch (InvalidKeyException e) {
-				Log.d(Config.LOGTAG, AxolotlService.getLogprefix(account) + "Encountered invalid IdentityKey in database for account" + account.getJid().toBareJid() + ", address: " + name);
+				Log.d(Config.LOGTAG, AxolotlServiceImpl.getLogprefix(account) + "Encountered invalid IdentityKey in database for account" + account.getJid().toBareJid() + ", address: " + name);
 			}
 		}
 		cursor.close();
@@ -965,7 +965,7 @@ public class DatabaseBackend extends SQLiteOpenHelper {
 			try {
 				identityKeys.add(new IdentityKey(Base64.decode(cursor.getString(cursor.getColumnIndex(SQLiteAxolotlStore.KEY)), Base64.DEFAULT), 0));
 			} catch (InvalidKeyException e) {
-				Log.d(Config.LOGTAG, AxolotlService.getLogprefix(account) + "Encountered invalid IdentityKey in database for account" + account.getJid().toBareJid() + ", address: " + name);
+				Log.d(Config.LOGTAG, AxolotlServiceImpl.getLogprefix(account) + "Encountered invalid IdentityKey in database for account" + account.getJid().toBareJid() + ", address: " + name);
 			}
 		}
 		cursor.close();
@@ -1095,7 +1095,7 @@ public class DatabaseBackend extends SQLiteOpenHelper {
 	}
 
 	public void recreateAxolotlDb(SQLiteDatabase db) {
-		Log.d(Config.LOGTAG, AxolotlService.LOGPREFIX + " : " + ">>> (RE)CREATING AXOLOTL DATABASE <<<");
+		Log.d(Config.LOGTAG, AxolotlServiceImpl.LOGPREFIX + " : " + ">>> (RE)CREATING AXOLOTL DATABASE <<<");
 		db.execSQL("DROP TABLE IF EXISTS " + SQLiteAxolotlStore.SESSION_TABLENAME);
 		db.execSQL(CREATE_SESSIONS_STATEMENT);
 		db.execSQL("DROP TABLE IF EXISTS " + SQLiteAxolotlStore.PREKEY_TABLENAME);
@@ -1108,7 +1108,7 @@ public class DatabaseBackend extends SQLiteOpenHelper {
 
 	public void wipeAxolotlDb(Account account) {
 		String accountName = account.getUuid();
-		Log.d(Config.LOGTAG, AxolotlService.getLogprefix(account) + ">>> WIPING AXOLOTL DATABASE FOR ACCOUNT " + accountName + " <<<");
+		Log.d(Config.LOGTAG, AxolotlServiceImpl.getLogprefix(account) + ">>> WIPING AXOLOTL DATABASE FOR ACCOUNT " + accountName + " <<<");
 		SQLiteDatabase db = this.getWritableDatabase();
 		String[] deleteArgs = {
 				accountName

src/main/java/eu/siacs/conversations/ui/ConversationActivity.java

@@ -50,6 +50,7 @@ import de.timroes.android.listview.EnhancedListView;
 import eu.siacs.conversations.Config;
 import eu.siacs.conversations.R;
 import eu.siacs.conversations.crypto.axolotl.AxolotlService;
+import eu.siacs.conversations.crypto.axolotl.AxolotlServiceImpl;
 import eu.siacs.conversations.crypto.axolotl.XmppAxolotlSession;
 import eu.siacs.conversations.entities.Account;
 import eu.siacs.conversations.entities.Blockable;
@@ -835,7 +836,7 @@ public class ConversationActivity extends XmppActivity
 							}
 							break;
 						case R.id.encryption_choice_axolotl:
-							Log.d(Config.LOGTAG, AxolotlService.getLogprefix(conversation.getAccount())
+							Log.d(Config.LOGTAG, AxolotlServiceImpl.getLogprefix(conversation.getAccount())
 									+ "Enabled axolotl for Contact " + conversation.getContact().getJid());
 							conversation.setNextEncryption(Message.ENCRYPTION_AXOLOTL);
 							item.setChecked(true);

src/main/java/eu/siacs/conversations/ui/SettingsActivity.java

@@ -7,6 +7,7 @@ import android.content.SharedPreferences;
 import android.content.SharedPreferences.OnSharedPreferenceChangeListener;
 import android.os.Build;
 import android.os.Bundle;
+import android.preference.CheckBoxPreference;
 import android.preference.ListPreference;
 import android.preference.Preference;
 import android.preference.PreferenceCategory;
@@ -123,6 +124,12 @@ public class SettingsActivity extends XmppActivity implements
                 return true;
             }
         });
+        // Avoid appearence of setting to enable or disable omemo in screen
+        Preference omemoEnabledPreference = this.mSettingsFragment.findPreference("omemo_enabled");
+        PreferenceCategory otherExpertSettingsGroup = (PreferenceCategory) this.mSettingsFragment.findPreference("other_expert_settings");
+        if (null != omemoEnabledPreference && null != otherExpertSettingsGroup) {
+            otherExpertSettingsGroup.removePreference(omemoEnabledPreference);
+        }
 	}
 
 	@Override

src/main/res/layout/activity_edit_account.xml

@@ -504,7 +504,8 @@
                     android:id="@+id/axolotl_fingerprint_box"
                     android:layout_width="wrap_content"
                     android:layout_height="match_parent"
-                    android:layout_marginTop="32dp">
+                    android:layout_marginTop="32dp"
+                    android:visibility="gone">
 
                     <LinearLayout
                         android:layout_width="wrap_content"

src/main/res/menu/encryption_choices.xml

@@ -7,7 +7,8 @@
             android:title="@string/encryption_choice_unencrypted"/>
         <item
             android:id="@+id/encryption_choice_axolotl"
-            android:title="@string/encryption_choice_omemo"/>
+            android:title="@string/encryption_choice_omemo"
+            android:visible="@bool/omemo_enabled"/>
         <item
             android:id="@+id/encryption_choice_otr"
             android:title="@string/encryption_choice_otr"/>

src/main/res/values/encryption_settings.xml

@@ -0,0 +1,4 @@
+<?xml version="1.0" encoding="utf-8"?>
+<resources>
+    <bool name="omemo_enabled">false</bool>
+</resources>

src/main/res/values/strings.xml

@@ -654,4 +654,6 @@
 	<string name="no_accounts">(No activated accounts)</string>
 	<string name="this_field_is_required">This field is required</string>
 	<string name="retry_decryption">Retry decryption</string>
+	<string name="pref_omemo_enabled_summary">Enable OMEMO?</string>
+	<string name="pref_omemo_enabled_title">Enable OMEMO</string>
 </resources>

src/main/res/xml/preferences.xml

@@ -227,7 +227,7 @@
                     android:summary="@string/pref_xa_on_silent_mode_summary"
                     android:title="@string/pref_xa_on_silent_mode"/>
             </PreferenceCategory>
-            <PreferenceCategory android:title="@string/pref_expert_options_other">
+            <PreferenceCategory android:key="other_expert_settings" android:title="@string/pref_expert_options_other">
                 <CheckBoxPreference
                     android:key="autojoin"
                     android:defaultValue="true"
@@ -251,6 +251,11 @@
                 <de.thedevstack.conversationsplus.ui.preferences.LogInformationPreference
                     android:summary="@string/pref_show_logcat_summary"
                     android:title="@string/pref_show_logcat_title"/>
+                <CheckBoxPreference
+                    android:defaultValue="@bool/omemo_enabled"
+                    android:key="omemo_enabled"
+                    android:summary="@string/pref_omemo_enabled_summary"
+                    android:title="@string/pref_omemo_enabled_title"/>
             </PreferenceCategory>
         </PreferenceScreen>