Fixes FS#147: Disable OMEMO

20 files changed, 1331 insertions, 981 deletions

diff --git a/src/main/java/de/thedevstack/conversationsplus/ConversationsPlusPreferences.java b/src/main/java/de/thedevstack/conversationsplus/ConversationsPlusPreferences.java
index 18e54362..20eca48a 100644
--- a/src/main/java/de/thedevstack/conversationsplus/ConversationsPlusPreferences.java
+++ b/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+"));
     }
diff --git a/src/main/java/eu/siacs/conversations/Config.java b/src/main/java/eu/siacs/conversations/Config.java
index 553abb9c..16db57e0 100644
--- a/src/main/java/eu/siacs/conversations/Config.java
+++ b/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() {
diff --git a/src/main/java/eu/siacs/conversations/crypto/axolotl/AxolotlService.java b/src/main/java/eu/siacs/conversations/crypto/axolotl/AxolotlService.java
index 949975aa..d8287aff 100644
--- a/src/main/java/eu/siacs/conversations/crypto/axolotl/AxolotlService.java
+++ b/src/main/java/eu/siacs/conversations/crypto/axolotl/AxolotlService.java
@@ -1,210 +1,36 @@
 package eu.siacs.conversations.crypto.axolotl;
 
-import android.os.Bundle;
-import android.security.KeyChain;
 import android.support.annotation.NonNull;
 import android.support.annotation.Nullable;
-import android.util.Log;
-import android.util.Pair;
 
-import org.bouncycastle.jce.provider.BouncyCastleProvider;
 import org.whispersystems.libaxolotl.AxolotlAddress;
 import org.whispersystems.libaxolotl.IdentityKey;
-import org.whispersystems.libaxolotl.IdentityKeyPair;
-import org.whispersystems.libaxolotl.InvalidKeyException;
-import org.whispersystems.libaxolotl.InvalidKeyIdException;
-import org.whispersystems.libaxolotl.SessionBuilder;
-import org.whispersystems.libaxolotl.UntrustedIdentityException;
-import org.whispersystems.libaxolotl.ecc.ECPublicKey;
-import org.whispersystems.libaxolotl.state.PreKeyBundle;
 import org.whispersystems.libaxolotl.state.PreKeyRecord;
 import org.whispersystems.libaxolotl.state.SignedPreKeyRecord;
-import org.whispersystems.libaxolotl.util.KeyHelper;
 
-import java.security.PrivateKey;
-import java.security.Security;
-import java.security.Signature;
 import java.security.cert.X509Certificate;
-import java.util.Arrays;
-import java.util.HashMap;
-import java.util.HashSet;
-import java.util.List;
-import java.util.Map;
-import java.util.Random;
 import java.util.Set;
 
-import eu.siacs.conversations.Config;
 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.parser.IqParser;
-import eu.siacs.conversations.services.XmppConnectionService;
-import eu.siacs.conversations.utils.CryptoHelper;
-import eu.siacs.conversations.utils.SerialSingleThreadExecutor;
-import eu.siacs.conversations.xml.Element;
 import eu.siacs.conversations.xmpp.OnAdvancedStreamFeaturesLoaded;
-import eu.siacs.conversations.xmpp.OnIqPacketReceived;
-import eu.siacs.conversations.xmpp.jid.InvalidJidException;
 import eu.siacs.conversations.xmpp.jid.Jid;
-import eu.siacs.conversations.xmpp.stanzas.IqPacket;
-
-public class AxolotlService implements OnAdvancedStreamFeaturesLoaded {
-
-	public static final String PEP_PREFIX = "eu.siacs.conversations.axolotl";
-	public static final String PEP_DEVICE_LIST = PEP_PREFIX + ".devicelist";
-	public static final String PEP_BUNDLES = PEP_PREFIX + ".bundles";
-	public static final String PEP_VERIFICATION = PEP_PREFIX + ".verification";
-
-	public static final String LOGPREFIX = "AxolotlService";
-
-	public static final int NUM_KEYS_TO_PUBLISH = 100;
-	public static final int publishTriesThreshold = 3;
-
-	private final Account account;
-	private final XmppConnectionService mXmppConnectionService;
-	private final SQLiteAxolotlStore axolotlStore;
-	private final SessionMap sessions;
-	private final Map<Jid, Set<Integer>> deviceIds;
-	private final Map<String, XmppAxolotlMessage> messageCache;
-	private final FetchStatusMap fetchStatusMap;
-	private final SerialSingleThreadExecutor executor;
-	private int numPublishTriesOnEmptyPep = 0;
-	private boolean pepBroken = false;
-
-	@Override
-	public void onAdvancedStreamFeaturesAvailable(Account account) {
-		if (account.getXmppConnection() != null && account.getXmppConnection().getFeatures().pep()) {
-			publishBundlesIfNeeded(true, false);
-		} else {
-			Log.d(Config.LOGTAG,account.getJid().toBareJid()+": skipping OMEMO initialization");
-		}
-	}
 
-	public boolean fetchMapHasErrors(Contact contact) {
-		Jid jid = contact.getJid().toBareJid();
-		if (deviceIds.get(jid) != null) {
-			for (Integer foreignId : this.deviceIds.get(jid)) {
-				AxolotlAddress address = new AxolotlAddress(jid.toString(), foreignId);
-				if (fetchStatusMap.getAll(address).containsValue(FetchStatus.ERROR)) {
-					return true;
-				}
-			}
-		}
-		return false;
-	}
+/**
+ * Created by tzur on 02.03.2016.
+ */
+public interface AxolotlService extends OnAdvancedStreamFeaturesLoaded {
 
-	private static class AxolotlAddressMap<T> {
-		protected Map<String, Map<Integer, T>> map;
-		protected final Object MAP_LOCK = new Object();
-
-		public AxolotlAddressMap() {
-			this.map = new HashMap<>();
-		}
-
-		public void put(AxolotlAddress address, T value) {
-			synchronized (MAP_LOCK) {
-				Map<Integer, T> devices = map.get(address.getName());
-				if (devices == null) {
-					devices = new HashMap<>();
-					map.put(address.getName(), devices);
-				}
-				devices.put(address.getDeviceId(), value);
-			}
-		}
-
-		public T get(AxolotlAddress address) {
-			synchronized (MAP_LOCK) {
-				Map<Integer, T> devices = map.get(address.getName());
-				if (devices == null) {
-					return null;
-				}
-				return devices.get(address.getDeviceId());
-			}
-		}
-
-		public Map<Integer, T> getAll(AxolotlAddress address) {
-			synchronized (MAP_LOCK) {
-				Map<Integer, T> devices = map.get(address.getName());
-				if (devices == null) {
-					return new HashMap<>();
-				}
-				return devices;
-			}
-		}
-
-		public boolean hasAny(AxolotlAddress address) {
-			synchronized (MAP_LOCK) {
-				Map<Integer, T> devices = map.get(address.getName());
-				return devices != null && !devices.isEmpty();
-			}
-		}
-
-		public void clear() {
-			map.clear();
-		}
+	String LOGPREFIX = "AxolotlService";
 
-	}
-
-	private static class SessionMap extends AxolotlAddressMap<XmppAxolotlSession> {
-		private final XmppConnectionService xmppConnectionService;
-		private final Account account;
-
-		public SessionMap(XmppConnectionService service, SQLiteAxolotlStore store, Account account) {
-			super();
-			this.xmppConnectionService = service;
-			this.account = account;
-			this.fillMap(store);
-		}
-
-		private void putDevicesForJid(String bareJid, List<Integer> deviceIds, SQLiteAxolotlStore store) {
-			for (Integer deviceId : deviceIds) {
-				AxolotlAddress axolotlAddress = new AxolotlAddress(bareJid, deviceId);
-				Log.d(Config.LOGTAG, AxolotlService.getLogprefix(account) + "Building session for remote address: " + axolotlAddress.toString());
-				IdentityKey identityKey = store.loadSession(axolotlAddress).getSessionState().getRemoteIdentityKey();
-				if(Config.X509_VERIFICATION) {
-					X509Certificate certificate = store.getFingerprintCertificate(identityKey.getFingerprint().replaceAll("\\s", ""));
-					if (certificate != null) {
-						Bundle information = CryptoHelper.extractCertificateInformation(certificate);
-						try {
-							final String cn = information.getString("subject_cn");
-							final Jid jid = Jid.fromString(bareJid);
-							Log.d(Config.LOGTAG,"setting common name for "+jid+" to "+cn);
-							account.getRoster().getContact(jid).setCommonName(cn);
-						} catch (final InvalidJidException ignored) {
-							//ignored
-						}
-					}
-				}
-				this.put(axolotlAddress, new XmppAxolotlSession(account, store, axolotlAddress, identityKey));
-			}
-		}
-
-		private void fillMap(SQLiteAxolotlStore store) {
-			List<Integer> deviceIds = store.getSubDeviceSessions(account.getJid().toBareJid().toString());
-			putDevicesForJid(account.getJid().toBareJid().toString(), deviceIds, store);
-			for (Contact contact : account.getRoster().getContacts()) {
-				Jid bareJid = contact.getJid().toBareJid();
-				String address = bareJid.toString();
-				deviceIds = store.getSubDeviceSessions(address);
-				putDevicesForJid(address, deviceIds, store);
-			}
-
-		}
-
-		@Override
-		public void put(AxolotlAddress address, XmppAxolotlSession value) {
-			super.put(address, value);
-			value.setNotFresh();
-			xmppConnectionService.syncRosterToDisk(account);
-		}
-
-		public void put(XmppAxolotlSession session) {
-			this.put(session.getRemoteAddress(), session);
-		}
-	}
+	String PEP_PREFIX = "eu.siacs.conversations.axolotl";
+	String PEP_DEVICE_LIST = PEP_PREFIX + ".devicelist";
+	String PEP_BUNDLES = PEP_PREFIX + ".bundles";
+	String PEP_VERIFICATION = PEP_PREFIX + ".verification";
 
-	public enum FetchStatus {
+	enum FetchStatus {
 		PENDING,
 		SUCCESS,
 		SUCCESS_VERIFIED,
@@ -212,793 +38,73 @@ public class AxolotlService implements OnAdvancedStreamFeaturesLoaded {
 		ERROR
 	}
 
-	private static class FetchStatusMap extends AxolotlAddressMap<FetchStatus> {
+	boolean fetchMapHasErrors(Contact contact);
 
-	}
+	String getOwnFingerprint();
 
-	public static String getLogprefix(Account account) {
-		return LOGPREFIX + " (" + account.getJid().toBareJid().toString() + "): ";
-	}
+	Set<IdentityKey> getKeysWithTrust(XmppAxolotlSession.Trust trust);
 
-	public AxolotlService(Account account, XmppConnectionService connectionService) {
-		if (Security.getProvider("BC") == null) {
-			Security.addProvider(new BouncyCastleProvider());
-		}
-		this.mXmppConnectionService = connectionService;
-		this.account = account;
-		this.axolotlStore = new SQLiteAxolotlStore(this.account, this.mXmppConnectionService);
-		this.deviceIds = new HashMap<>();
-		this.messageCache = new HashMap<>();
-		this.sessions = new SessionMap(mXmppConnectionService, axolotlStore, account);
-		this.fetchStatusMap = new FetchStatusMap();
-		this.executor = new SerialSingleThreadExecutor();
-	}
-
-	public String getOwnFingerprint() {
-		return axolotlStore.getIdentityKeyPair().getPublicKey().getFingerprint().replaceAll("\\s", "");
-	}
+	Set<IdentityKey> getKeysWithTrust(XmppAxolotlSession.Trust trust, Contact contact);
 
-	public Set<IdentityKey> getKeysWithTrust(XmppAxolotlSession.Trust trust) {
-		return axolotlStore.getContactKeysWithTrust(account.getJid().toBareJid().toString(), trust);
-	}
-
-	public Set<IdentityKey> getKeysWithTrust(XmppAxolotlSession.Trust trust, Contact contact) {
-		return axolotlStore.getContactKeysWithTrust(contact.getJid().toBareJid().toString(), trust);
-	}
-
-	public long getNumTrustedKeys(Contact contact) {
-		return axolotlStore.getContactNumTrustedKeys(contact.getJid().toBareJid().toString());
-	}
-
-	private AxolotlAddress getAddressForJid(Jid jid) {
-		return new AxolotlAddress(jid.toString(), 0);
-	}
-
-	private Set<XmppAxolotlSession> findOwnSessions() {
-		AxolotlAddress ownAddress = getAddressForJid(account.getJid().toBareJid());
-		return new HashSet<>(this.sessions.getAll(ownAddress).values());
-	}
-
-	private Set<XmppAxolotlSession> findSessionsforContact(Contact contact) {
-		AxolotlAddress contactAddress = getAddressForJid(contact.getJid());
-		return new HashSet<>(this.sessions.getAll(contactAddress).values());
-	}
-
-	public Set<String> getFingerprintsForOwnSessions() {
-		Set<String> fingerprints = new HashSet<>();
-		for (XmppAxolotlSession session : findOwnSessions()) {
-			fingerprints.add(session.getFingerprint());
-		}
-		return fingerprints;
-	}
-
-	public Set<String> getFingerprintsForContact(final Contact contact) {
-		Set<String> fingerprints = new HashSet<>();
-		for (XmppAxolotlSession session : findSessionsforContact(contact)) {
-			fingerprints.add(session.getFingerprint());
-		}
-		return fingerprints;
-	}
-
-	private boolean hasAny(Contact contact) {
-		AxolotlAddress contactAddress = getAddressForJid(contact.getJid());
-		return sessions.hasAny(contactAddress);
-	}
-
-	public boolean isPepBroken() {
-		return this.pepBroken;
-	}
-
-	public void regenerateKeys(boolean wipeOther) {
-		axolotlStore.regenerate();
-		sessions.clear();
-		fetchStatusMap.clear();
-		publishBundlesIfNeeded(true, wipeOther);
-	}
-
-	public int getOwnDeviceId() {
-		return axolotlStore.getLocalRegistrationId();
-	}
-
-	public Set<Integer> getOwnDeviceIds() {
-		return this.deviceIds.get(account.getJid().toBareJid());
-	}
-
-	private void setTrustOnSessions(final Jid jid, @NonNull final Set<Integer> deviceIds,
-	                                final XmppAxolotlSession.Trust from,
-	                                final XmppAxolotlSession.Trust to) {
-		for (Integer deviceId : deviceIds) {
-			AxolotlAddress address = new AxolotlAddress(jid.toBareJid().toString(), deviceId);
-			XmppAxolotlSession session = sessions.get(address);
-			if (session != null && session.getFingerprint() != null
-					&& session.getTrust() == from) {
-				session.setTrust(to);
-			}
-		}
-	}
+	long getNumTrustedKeys(Contact contact);
 
-	public void registerDevices(final Jid jid, @NonNull final Set<Integer> deviceIds) {
-		if (jid.toBareJid().equals(account.getJid().toBareJid())) {
-			if (!deviceIds.isEmpty()) {
-				Log.d(Config.LOGTAG, getLogprefix(account) + "Received non-empty own device list. Resetting publish attemps and pepBroken status.");
-				pepBroken = false;
-				numPublishTriesOnEmptyPep = 0;
-			}
-			if (deviceIds.contains(getOwnDeviceId())) {
-				deviceIds.remove(getOwnDeviceId());
-			} else {
-				publishOwnDeviceId(deviceIds);
-			}
-			for (Integer deviceId : deviceIds) {
-				AxolotlAddress ownDeviceAddress = new AxolotlAddress(jid.toBareJid().toString(), deviceId);
-				if (sessions.get(ownDeviceAddress) == null) {
-					buildSessionFromPEP(ownDeviceAddress);
-				}
-			}
-		}
-		Set<Integer> expiredDevices = new HashSet<>(axolotlStore.getSubDeviceSessions(jid.toBareJid().toString()));
-		expiredDevices.removeAll(deviceIds);
-		setTrustOnSessions(jid, expiredDevices, XmppAxolotlSession.Trust.TRUSTED,
-				XmppAxolotlSession.Trust.INACTIVE_TRUSTED);
-		setTrustOnSessions(jid, expiredDevices, XmppAxolotlSession.Trust.TRUSTED_X509,
-				XmppAxolotlSession.Trust.INACTIVE_TRUSTED_X509);
-		setTrustOnSessions(jid, expiredDevices, XmppAxolotlSession.Trust.UNDECIDED,
-				XmppAxolotlSession.Trust.INACTIVE_UNDECIDED);
-		setTrustOnSessions(jid, expiredDevices, XmppAxolotlSession.Trust.UNTRUSTED,
-				XmppAxolotlSession.Trust.INACTIVE_UNTRUSTED);
-		Set<Integer> newDevices = new HashSet<>(deviceIds);
-		setTrustOnSessions(jid, newDevices, XmppAxolotlSession.Trust.INACTIVE_TRUSTED,
-				XmppAxolotlSession.Trust.TRUSTED);
-		setTrustOnSessions(jid, newDevices, XmppAxolotlSession.Trust.INACTIVE_TRUSTED_X509,
-				XmppAxolotlSession.Trust.TRUSTED_X509);
-		setTrustOnSessions(jid, newDevices, XmppAxolotlSession.Trust.INACTIVE_UNDECIDED,
-				XmppAxolotlSession.Trust.UNDECIDED);
-		setTrustOnSessions(jid, newDevices, XmppAxolotlSession.Trust.INACTIVE_UNTRUSTED,
-				XmppAxolotlSession.Trust.UNTRUSTED);
-		this.deviceIds.put(jid, deviceIds);
-		mXmppConnectionService.keyStatusUpdated(null);
-	}
+	Set<String> getFingerprintsForOwnSessions();
 
-	public void wipeOtherPepDevices() {
-		if (pepBroken) {
-			Log.d(Config.LOGTAG, getLogprefix(account) + "wipeOtherPepDevices called, but PEP is broken. Ignoring... ");
-			return;
-		}
-		Set<Integer> deviceIds = new HashSet<>();
-		deviceIds.add(getOwnDeviceId());
-		IqPacket publish = mXmppConnectionService.getIqGenerator().publishDeviceIds(deviceIds);
-		Log.d(Config.LOGTAG, AxolotlService.getLogprefix(account) + "Wiping all other devices from Pep:" + publish);
-		mXmppConnectionService.sendIqPacket(account, publish, new OnIqPacketReceived() {
-			@Override
-			public void onIqPacketReceived(Account account, IqPacket packet) {
-				// TODO: implement this!
-			}
-		});
-	}
+	Set<String> getFingerprintsForContact(Contact contact);
 
-	public void purgeKey(final String fingerprint) {
-		axolotlStore.setFingerprintTrust(fingerprint.replaceAll("\\s", ""), XmppAxolotlSession.Trust.COMPROMISED);
-	}
+	boolean isPepBroken();
 
-	public void publishOwnDeviceIdIfNeeded() {
-		if (pepBroken) {
-			Log.d(Config.LOGTAG, getLogprefix(account) + "publishOwnDeviceIdIfNeeded called, but PEP is broken. Ignoring... ");
-			return;
-		}
-		IqPacket packet = mXmppConnectionService.getIqGenerator().retrieveDeviceIds(account.getJid().toBareJid());
-		mXmppConnectionService.sendIqPacket(account, packet, new OnIqPacketReceived() {
-			@Override
-			public void onIqPacketReceived(Account account, IqPacket packet) {
-				if (packet.getType() == IqPacket.TYPE.TIMEOUT) {
-					Log.d(Config.LOGTAG, getLogprefix(account) + "Timeout received while retrieving own Device Ids.");
-				} else {
-					Element item = mXmppConnectionService.getIqParser().getItem(packet);
-					Set<Integer> deviceIds = mXmppConnectionService.getIqParser().deviceIds(item);
-					if (!deviceIds.contains(getOwnDeviceId())) {
-						publishOwnDeviceId(deviceIds);
-					}
-				}
-			}
-		});
-	}
+	void regenerateKeys(boolean wipeOther);
 
-	public void publishOwnDeviceId(Set<Integer> deviceIds) {
-		Set<Integer> deviceIdsCopy = new HashSet<>(deviceIds);
-		if (!deviceIdsCopy.contains(getOwnDeviceId())) {
-			Log.d(Config.LOGTAG, AxolotlService.getLogprefix(account) + "Own device " + getOwnDeviceId() + " not in PEP devicelist.");
-			if (deviceIdsCopy.isEmpty()) {
-				if (numPublishTriesOnEmptyPep >= publishTriesThreshold) {
-					Log.w(Config.LOGTAG, getLogprefix(account) + "Own device publish attempt threshold exceeded, aborting...");
-					pepBroken = true;
-					return;
-				} else {
-					numPublishTriesOnEmptyPep++;
-					Log.w(Config.LOGTAG, getLogprefix(account) + "Own device list empty, attempting to publish (try " + numPublishTriesOnEmptyPep + ")");
-				}
-			} else {
-				numPublishTriesOnEmptyPep = 0;
-			}
-			deviceIdsCopy.add(getOwnDeviceId());
-			IqPacket publish = mXmppConnectionService.getIqGenerator().publishDeviceIds(deviceIdsCopy);
-			mXmppConnectionService.sendIqPacket(account, publish, new OnIqPacketReceived() {
-				@Override
-				public void onIqPacketReceived(Account account, IqPacket packet) {
-					if (packet.getType() != IqPacket.TYPE.RESULT) {
-						Log.d(Config.LOGTAG, getLogprefix(account) + "Error received while publishing own device id" + packet.findChild("error"));
-					}
-				}
-			});
-		}
-	}
+	int getOwnDeviceId();
 
-	public void publishDeviceVerificationAndBundle(final SignedPreKeyRecord signedPreKeyRecord,
-												   final Set<PreKeyRecord> preKeyRecords,
-												   final boolean announceAfter,
-												   final boolean wipe) {
-		try {
-			IdentityKey axolotlPublicKey = axolotlStore.getIdentityKeyPair().getPublicKey();
-			PrivateKey x509PrivateKey = KeyChain.getPrivateKey(mXmppConnectionService, account.getPrivateKeyAlias());
-			X509Certificate[] chain = KeyChain.getCertificateChain(mXmppConnectionService, account.getPrivateKeyAlias());
-			Signature verifier = Signature.getInstance("sha256WithRSA");
-			verifier.initSign(x509PrivateKey,mXmppConnectionService.getRNG());
-			verifier.update(axolotlPublicKey.serialize());
-			byte[] signature = verifier.sign();
-			IqPacket packet = mXmppConnectionService.getIqGenerator().publishVerification(signature, chain, getOwnDeviceId());
-			Log.d(Config.LOGTAG, AxolotlService.getLogprefix(account) + ": publish verification for device "+getOwnDeviceId());
-			mXmppConnectionService.sendIqPacket(account, packet, new OnIqPacketReceived() {
-				@Override
-				public void onIqPacketReceived(Account account, IqPacket packet) {
-					publishDeviceBundle(signedPreKeyRecord, preKeyRecords, announceAfter, wipe);
-				}
-			});
-		} catch (Exception  e) {
-			e.printStackTrace();
-		}
-	}
+	Set<Integer> getOwnDeviceIds();
 
-	public void publishBundlesIfNeeded(final boolean announce, final boolean wipe) {
-		if (pepBroken) {
-			Log.d(Config.LOGTAG, getLogprefix(account) + "publishBundlesIfNeeded called, but PEP is broken. Ignoring... ");
-			return;
-		}
-		IqPacket packet = mXmppConnectionService.getIqGenerator().retrieveBundlesForDevice(account.getJid().toBareJid(), getOwnDeviceId());
-		mXmppConnectionService.sendIqPacket(account, packet, new OnIqPacketReceived() {
-			@Override
-			public void onIqPacketReceived(Account account, IqPacket packet) {
-
-				if (packet.getType() == IqPacket.TYPE.TIMEOUT) {
-					return; //ignore timeout. do nothing
-				}
-
-				if (packet.getType() == IqPacket.TYPE.ERROR) {
-					Element error = packet.findChild("error");
-					if (error == null || !error.hasChild("item-not-found")) {
-						pepBroken = true;
-						Log.w(Config.LOGTAG, AxolotlService.getLogprefix(account) + "request for device bundles came back with something other than item-not-found" + packet);
-						return;
-					}
-				}
-
-				PreKeyBundle bundle = mXmppConnectionService.getIqParser().bundle(packet);
-				Map<Integer, ECPublicKey> keys = mXmppConnectionService.getIqParser().preKeyPublics(packet);
-				boolean flush = false;
-				if (bundle == null) {
-					Log.w(Config.LOGTAG, AxolotlService.getLogprefix(account) + "Received invalid bundle:" + packet);
-					bundle = new PreKeyBundle(-1, -1, -1, null, -1, null, null, null);
-					flush = true;
-				}
-				if (keys == null) {
-					Log.w(Config.LOGTAG, AxolotlService.getLogprefix(account) + "Received invalid prekeys:" + packet);
-				}
-				try {
-					boolean changed = false;
-					// Validate IdentityKey
-					IdentityKeyPair identityKeyPair = axolotlStore.getIdentityKeyPair();
-					if (flush || !identityKeyPair.getPublicKey().equals(bundle.getIdentityKey())) {
-						Log.i(Config.LOGTAG, AxolotlService.getLogprefix(account) + "Adding own IdentityKey " + identityKeyPair.getPublicKey() + " to PEP.");
-						changed = true;
-					}
-
-					// Validate signedPreKeyRecord + ID
-					SignedPreKeyRecord signedPreKeyRecord;
-					int numSignedPreKeys = axolotlStore.loadSignedPreKeys().size();
-					try {
-						signedPreKeyRecord = axolotlStore.loadSignedPreKey(bundle.getSignedPreKeyId());
-						if (flush
-								|| !bundle.getSignedPreKey().equals(signedPreKeyRecord.getKeyPair().getPublicKey())
-								|| !Arrays.equals(bundle.getSignedPreKeySignature(), signedPreKeyRecord.getSignature())) {
-							Log.i(Config.LOGTAG, AxolotlService.getLogprefix(account) + "Adding new signedPreKey with ID " + (numSignedPreKeys + 1) + " to PEP.");
-							signedPreKeyRecord = KeyHelper.generateSignedPreKey(identityKeyPair, numSignedPreKeys + 1);
-							axolotlStore.storeSignedPreKey(signedPreKeyRecord.getId(), signedPreKeyRecord);
-							changed = true;
-						}
-					} catch (InvalidKeyIdException e) {
-						Log.i(Config.LOGTAG, AxolotlService.getLogprefix(account) + "Adding new signedPreKey with ID " + (numSignedPreKeys + 1) + " to PEP.");
-						signedPreKeyRecord = KeyHelper.generateSignedPreKey(identityKeyPair, numSignedPreKeys + 1);
-						axolotlStore.storeSignedPreKey(signedPreKeyRecord.getId(), signedPreKeyRecord);
-						changed = true;
-					}
-
-					// Validate PreKeys
-					Set<PreKeyRecord> preKeyRecords = new HashSet<>();
-					if (keys != null) {
-						for (Integer id : keys.keySet()) {
-							try {
-								PreKeyRecord preKeyRecord = axolotlStore.loadPreKey(id);
-								if (preKeyRecord.getKeyPair().getPublicKey().equals(keys.get(id))) {
-									preKeyRecords.add(preKeyRecord);
-								}
-							} catch (InvalidKeyIdException ignored) {
-							}
-						}
-					}
-					int newKeys = NUM_KEYS_TO_PUBLISH - preKeyRecords.size();
-					if (newKeys > 0) {
-						List<PreKeyRecord> newRecords = KeyHelper.generatePreKeys(
-								axolotlStore.getCurrentPreKeyId() + 1, newKeys);
-						preKeyRecords.addAll(newRecords);
-						for (PreKeyRecord record : newRecords) {
-							axolotlStore.storePreKey(record.getId(), record);
-						}
-						changed = true;
-						Log.i(Config.LOGTAG, AxolotlService.getLogprefix(account) + "Adding " + newKeys + " new preKeys to PEP.");
-					}
-
-
-					if (changed) {
-						if (account.getPrivateKeyAlias() != null && Config.X509_VERIFICATION) {
-							mXmppConnectionService.publishDisplayName(account);
-							publishDeviceVerificationAndBundle(signedPreKeyRecord, preKeyRecords, announce, wipe);
-						} else {
-							publishDeviceBundle(signedPreKeyRecord, preKeyRecords, announce, wipe);
-						}
-					} else {
-						Log.d(Config.LOGTAG, getLogprefix(account) + "Bundle " + getOwnDeviceId() + " in PEP was current");
-						if (wipe) {
-							wipeOtherPepDevices();
-						} else if (announce) {
-							Log.d(Config.LOGTAG, getLogprefix(account) + "Announcing device " + getOwnDeviceId());
-							publishOwnDeviceIdIfNeeded();
-						}
-					}
-				} catch (InvalidKeyException e) {
-					Log.e(Config.LOGTAG, AxolotlService.getLogprefix(account) + "Failed to publish bundle " + getOwnDeviceId() + ", reason: " + e.getMessage());
-				}
-			}
-		});
-	}
+	void registerDevices(Jid jid, @NonNull Set<Integer> deviceIds);
 
-	private void publishDeviceBundle(SignedPreKeyRecord signedPreKeyRecord,
-									 Set<PreKeyRecord> preKeyRecords,
-									 final boolean announceAfter,
-									 final boolean wipe) {
-		IqPacket publish = mXmppConnectionService.getIqGenerator().publishBundles(
-				signedPreKeyRecord, axolotlStore.getIdentityKeyPair().getPublicKey(),
-				preKeyRecords, getOwnDeviceId());
-		Log.d(Config.LOGTAG, AxolotlService.getLogprefix(account) + ": Bundle " + getOwnDeviceId() + " in PEP not current. Publishing: " + publish);
-		mXmppConnectionService.sendIqPacket(account, publish, new OnIqPacketReceived() {
-			@Override
-			public void onIqPacketReceived(Account account, IqPacket packet) {
-				if (packet.getType() == IqPacket.TYPE.RESULT) {
-					Log.d(Config.LOGTAG, AxolotlService.getLogprefix(account) + "Successfully published bundle. ");
-					if (wipe) {
-						wipeOtherPepDevices();
-					} else if (announceAfter) {
-						Log.d(Config.LOGTAG, getLogprefix(account) + "Announcing device " + getOwnDeviceId());
-						publishOwnDeviceIdIfNeeded();
-					}
-				} else {
-					Log.d(Config.LOGTAG, getLogprefix(account) + "Error received while publishing bundle: " + packet.findChild("error"));
-				}
-			}
-		});
-	}
+	void wipeOtherPepDevices();
 
-	public boolean isContactAxolotlCapable(Contact contact) {
-		Jid jid = contact.getJid().toBareJid();
-		return hasAny(contact) ||
-				(deviceIds.containsKey(jid) && !deviceIds.get(jid).isEmpty());
-	}
+	void purgeKey(String fingerprint);
 
-	public XmppAxolotlSession.Trust getFingerprintTrust(String fingerprint) {
-		return axolotlStore.getFingerprintTrust(fingerprint);
-	}
+	void publishOwnDeviceIdIfNeeded();
 
-	public X509Certificate getFingerprintCertificate(String fingerprint) {
-		return axolotlStore.getFingerprintCertificate(fingerprint);
-	}
+	void publishOwnDeviceId(Set<Integer> deviceIds);
 
-	public void setFingerprintTrust(String fingerprint, XmppAxolotlSession.Trust trust) {
-		axolotlStore.setFingerprintTrust(fingerprint, trust);
-	}
+	void publishDeviceVerificationAndBundle(SignedPreKeyRecord signedPreKeyRecord,
+											Set<PreKeyRecord> preKeyRecords,
+											boolean announceAfter,
+											boolean wipe);
 
-	private void verifySessionWithPEP(final XmppAxolotlSession session) {
-		Log.d(Config.LOGTAG, "trying to verify fresh session (" + session.getRemoteAddress().getName() + ") with pep");
-		final AxolotlAddress address = session.getRemoteAddress();
-		final IdentityKey identityKey = session.getIdentityKey();
-		try {
-			IqPacket packet = mXmppConnectionService.getIqGenerator().retrieveVerificationForDevice(Jid.fromString(address.getName()), address.getDeviceId());
-			mXmppConnectionService.sendIqPacket(account, packet, new OnIqPacketReceived() {
-				@Override
-				public void onIqPacketReceived(Account account, IqPacket packet) {
-					Pair<X509Certificate[],byte[]> verification = mXmppConnectionService.getIqParser().verification(packet);
-					if (verification != null) {
-						try {
-							Signature verifier = Signature.getInstance("sha256WithRSA");
-							verifier.initVerify(verification.first[0]);
-							verifier.update(identityKey.serialize());
-							if (verifier.verify(verification.second)) {
-								try {
-									mXmppConnectionService.getMemorizingTrustManager().getNonInteractive().checkClientTrusted(verification.first, "RSA");
-									String fingerprint = session.getFingerprint();
-									Log.d(Config.LOGTAG, "verified session with x.509 signature. fingerprint was: "+fingerprint);
-									setFingerprintTrust(fingerprint, XmppAxolotlSession.Trust.TRUSTED_X509);
-									axolotlStore.setFingerprintCertificate(fingerprint, verification.first[0]);
-									fetchStatusMap.put(address, FetchStatus.SUCCESS_VERIFIED);
-									Bundle information = CryptoHelper.extractCertificateInformation(verification.first[0]);
-									try {
-										final String cn = information.getString("subject_cn");
-										final Jid jid = Jid.fromString(address.getName());
-										Log.d(Config.LOGTAG,"setting common name for "+jid+" to "+cn);
-										account.getRoster().getContact(jid).setCommonName(cn);
-									} catch (final InvalidJidException ignored) {
-										//ignored
-									}
-									finishBuildingSessionsFromPEP(address);
-									return;
-								} catch (Exception e) {
-									Log.d(Config.LOGTAG,"could not verify certificate");
-								}
-							}
-						} catch (Exception e) {
-							Log.d(Config.LOGTAG, "error during verification " + e.getMessage());
-						}
-					} else {
-						Log.d(Config.LOGTAG,"no verification found");
-					}
-					fetchStatusMap.put(address, FetchStatus.SUCCESS);
-					finishBuildingSessionsFromPEP(address);
-				}
-			});
-		} catch (InvalidJidException e) {
-			fetchStatusMap.put(address, FetchStatus.SUCCESS);
-			finishBuildingSessionsFromPEP(address);
-		}
-	}
+	void publishBundlesIfNeeded(boolean announce, boolean wipe);
 
-	private void finishBuildingSessionsFromPEP(final AxolotlAddress address) {
-		AxolotlAddress ownAddress = new AxolotlAddress(account.getJid().toBareJid().toString(), 0);
-		if (!fetchStatusMap.getAll(ownAddress).containsValue(FetchStatus.PENDING)
-				&& !fetchStatusMap.getAll(address).containsValue(FetchStatus.PENDING)) {
-			FetchStatus report = null;
-			if (fetchStatusMap.getAll(ownAddress).containsValue(FetchStatus.SUCCESS_VERIFIED)
-					| fetchStatusMap.getAll(address).containsValue(FetchStatus.SUCCESS_VERIFIED)) {
-				report = FetchStatus.SUCCESS_VERIFIED;
-			} else if (fetchStatusMap.getAll(ownAddress).containsValue(FetchStatus.ERROR)
-					|| fetchStatusMap.getAll(address).containsValue(FetchStatus.ERROR)) {
-				report = FetchStatus.ERROR;
-			}
-			mXmppConnectionService.keyStatusUpdated(report);
-		}
-	}
+	boolean isContactAxolotlCapable(Contact contact);
 
-	private void buildSessionFromPEP(final AxolotlAddress address) {
-		Log.i(Config.LOGTAG, AxolotlService.getLogprefix(account) + "Building new sesstion for " + address.toString());
-		if (address.getDeviceId() == getOwnDeviceId()) {
-			throw new AssertionError("We should NEVER build a session with ourselves. What happened here?!");
-		}
-
-		try {
-			IqPacket bundlesPacket = mXmppConnectionService.getIqGenerator().retrieveBundlesForDevice(
-					Jid.fromString(address.getName()), address.getDeviceId());
-			Log.d(Config.LOGTAG, AxolotlService.getLogprefix(account) + "Retrieving bundle: " + bundlesPacket);
-			mXmppConnectionService.sendIqPacket(account, bundlesPacket, new OnIqPacketReceived() {
-
-				@Override
-				public void onIqPacketReceived(Account account, IqPacket packet) {
-					if (packet.getType() == IqPacket.TYPE.TIMEOUT) {
-						fetchStatusMap.put(address, FetchStatus.TIMEOUT);
-					} else if (packet.getType() == IqPacket.TYPE.RESULT) {
-						Log.d(Config.LOGTAG, AxolotlService.getLogprefix(account) + "Received preKey IQ packet, processing...");
-						final IqParser parser = mXmppConnectionService.getIqParser();
-						final List<PreKeyBundle> preKeyBundleList = parser.preKeys(packet);
-						final PreKeyBundle bundle = parser.bundle(packet);
-						if (preKeyBundleList.isEmpty() || bundle == null) {
-							Log.e(Config.LOGTAG, AxolotlService.getLogprefix(account) + "preKey IQ packet invalid: " + packet);
-							fetchStatusMap.put(address, FetchStatus.ERROR);
-							finishBuildingSessionsFromPEP(address);
-							return;
-						}
-						Random random = new Random();
-						final PreKeyBundle preKey = preKeyBundleList.get(random.nextInt(preKeyBundleList.size()));
-						if (preKey == null) {
-							//should never happen
-							fetchStatusMap.put(address, FetchStatus.ERROR);
-							finishBuildingSessionsFromPEP(address);
-							return;
-						}
-
-						final PreKeyBundle preKeyBundle = new PreKeyBundle(0, address.getDeviceId(),
-								preKey.getPreKeyId(), preKey.getPreKey(),
-								bundle.getSignedPreKeyId(), bundle.getSignedPreKey(),
-								bundle.getSignedPreKeySignature(), bundle.getIdentityKey());
-
-						try {
-							SessionBuilder builder = new SessionBuilder(axolotlStore, address);
-							builder.process(preKeyBundle);
-							XmppAxolotlSession session = new XmppAxolotlSession(account, axolotlStore, address, bundle.getIdentityKey());
-							sessions.put(address, session);
-							if (Config.X509_VERIFICATION) {
-								verifySessionWithPEP(session);
-							} else {
-								fetchStatusMap.put(address, FetchStatus.SUCCESS);
-								finishBuildingSessionsFromPEP(address);
-							}
-						} catch (UntrustedIdentityException | InvalidKeyException e) {
-							Log.e(Config.LOGTAG, AxolotlService.getLogprefix(account) + "Error building session for " + address + ": "
-									+ e.getClass().getName() + ", " + e.getMessage());
-							fetchStatusMap.put(address, FetchStatus.ERROR);
-							finishBuildingSessionsFromPEP(address);
-						}
-					} else {
-						fetchStatusMap.put(address, FetchStatus.ERROR);
-						Log.d(Config.LOGTAG, getLogprefix(account) + "Error received while building session:" + packet.findChild("error"));
-						finishBuildingSessionsFromPEP(address);
-					}
-				}
-			});
-		} catch (InvalidJidException e) {
-			Log.e(Config.LOGTAG, AxolotlService.getLogprefix(account) + "Got address with invalid jid: " + address.getName());
-		}
-	}
+	XmppAxolotlSession.Trust getFingerprintTrust(String fingerprint);
 
-	public Set<AxolotlAddress> findDevicesWithoutSession(final Conversation conversation) {
-		return findDevicesWithoutSession(conversation.getContact().getJid().toBareJid());
-	}
+	X509Certificate getFingerprintCertificate(String fingerprint);
 
-	public Set<AxolotlAddress> findDevicesWithoutSession(final Jid contactJid) {
-		Log.d(Config.LOGTAG, AxolotlService.getLogprefix(account) + "Finding devices without session for " + contactJid);
-		Set<AxolotlAddress> addresses = new HashSet<>();
-		if (deviceIds.get(contactJid) != null) {
-			for (Integer foreignId : this.deviceIds.get(contactJid)) {
-				AxolotlAddress address = new AxolotlAddress(contactJid.toString(), foreignId);
-				if (sessions.get(address) == null) {
-					IdentityKey identityKey = axolotlStore.loadSession(address).getSessionState().getRemoteIdentityKey();
-					if (identityKey != null) {
-						Log.d(Config.LOGTAG, AxolotlService.getLogprefix(account) + "Already have session for " + address.toString() + ", adding to cache...");
-						XmppAxolotlSession session = new XmppAxolotlSession(account, axolotlStore, address, identityKey);
-						sessions.put(address, session);
-					} else {
-						Log.d(Config.LOGTAG, AxolotlService.getLogprefix(account) + "Found device " + contactJid + ":" + foreignId);
-						if (fetchStatusMap.get(address) != FetchStatus.ERROR) {
-							addresses.add(address);
-						} else {
-							Log.d(Config.LOGTAG,getLogprefix(account)+"skipping over "+address+" because it's broken");
-						}
-					}
-				}
-			}
-		} else {
-			Log.w(Config.LOGTAG, AxolotlService.getLogprefix(account) + "Have no target devices in PEP!");
-		}
-		if (deviceIds.get(account.getJid().toBareJid()) != null) {
-			for (Integer ownId : this.deviceIds.get(account.getJid().toBareJid())) {
-				AxolotlAddress address = new AxolotlAddress(account.getJid().toBareJid().toString(), ownId);
-				if (sessions.get(address) == null) {
-					IdentityKey identityKey = axolotlStore.loadSession(address).getSessionState().getRemoteIdentityKey();
-					if (identityKey != null) {
-						Log.d(Config.LOGTAG, AxolotlService.getLogprefix(account) + "Already have session for " + address.toString() + ", adding to cache...");
-						XmppAxolotlSession session = new XmppAxolotlSession(account, axolotlStore, address, identityKey);
-						sessions.put(address, session);
-					} else {
-						Log.d(Config.LOGTAG, AxolotlService.getLogprefix(account) + "Found device " + account.getJid().toBareJid() + ":" + ownId);
-						if (fetchStatusMap.get(address) != FetchStatus.ERROR) {
-							addresses.add(address);
-						} else {
-							Log.d(Config.LOGTAG,getLogprefix(account)+"skipping over "+address+" because it's broken");
-						}
-					}
-				}
-			}
-		}
-
-		return addresses;
-	}
+	void setFingerprintTrust(String fingerprint, XmppAxolotlSession.Trust trust);
 
-	public boolean createSessionsIfNeeded(final Conversation conversation) {
-		Log.i(Config.LOGTAG, AxolotlService.getLogprefix(account) + "Creating axolotl sessions if needed...");
-		boolean newSessions = false;
-		Set<AxolotlAddress> addresses = findDevicesWithoutSession(conversation);
-		for (AxolotlAddress address : addresses) {
-			Log.d(Config.LOGTAG, AxolotlService.getLogprefix(account) + "Processing device: " + address.toString());
-			FetchStatus status = fetchStatusMap.get(address);
-			if (status == null || status == FetchStatus.TIMEOUT) {
-				fetchStatusMap.put(address, FetchStatus.PENDING);
-				this.buildSessionFromPEP(address);
-				newSessions = true;
-			} else if (status == FetchStatus.PENDING) {
-				newSessions = true;
-			} else {
-				Log.d(Config.LOGTAG, AxolotlService.getLogprefix(account) + "Already fetching bundle for " + address.toString());
-			}
-		}
-
-		return newSessions;
-	}
+	Set<AxolotlAddress> findDevicesWithoutSession(Conversation conversation);
 
-	public boolean trustedSessionVerified(final Conversation conversation) {
-		Set<XmppAxolotlSession> sessions = findSessionsforContact(conversation.getContact());
-		sessions.addAll(findOwnSessions());
-		boolean verified = false;
-		for(XmppAxolotlSession session : sessions) {
-			if (session.getTrust().trusted()) {
-				if (session.getTrust() == XmppAxolotlSession.Trust.TRUSTED_X509) {
-					verified = true;
-				} else {
-					return false;
-				}
-			}
-		}
-		return verified;
-	}
+	Set<AxolotlAddress> findDevicesWithoutSession(Jid contactJid);
 
-	public boolean hasPendingKeyFetches(Account account, Contact contact) {
-		AxolotlAddress ownAddress = new AxolotlAddress(account.getJid().toBareJid().toString(), 0);
-		AxolotlAddress foreignAddress = new AxolotlAddress(contact.getJid().toBareJid().toString(), 0);
-		return fetchStatusMap.getAll(ownAddress).containsValue(FetchStatus.PENDING)
-				|| fetchStatusMap.getAll(foreignAddress).containsValue(FetchStatus.PENDING);
+	boolean createSessionsIfNeeded(Conversation conversation);
 
-	}
+	boolean trustedSessionVerified(Conversation conversation);
 
-	@Nullable
-	private XmppAxolotlMessage buildHeader(Contact contact) {
-		final XmppAxolotlMessage axolotlMessage = new XmppAxolotlMessage(
-				contact.getJid().toBareJid(), getOwnDeviceId());
-
-		Set<XmppAxolotlSession> contactSessions = findSessionsforContact(contact);
-		Set<XmppAxolotlSession> ownSessions = findOwnSessions();
-		if (contactSessions.isEmpty()) {
-			return null;
-		}
-		Log.d(Config.LOGTAG, AxolotlService.getLogprefix(account) + "Building axolotl foreign keyElements...");
-		for (XmppAxolotlSession session : contactSessions) {
-			Log.v(Config.LOGTAG, AxolotlService.getLogprefix(account) + session.getRemoteAddress().toString());
-			axolotlMessage.addDevice(session);
-		}
-		Log.d(Config.LOGTAG, AxolotlService.getLogprefix(account) + "Building axolotl own keyElements...");
-		for (XmppAxolotlSession session : ownSessions) {
-			Log.v(Config.LOGTAG, AxolotlService.getLogprefix(account) + session.getRemoteAddress().toString());
-			axolotlMessage.addDevice(session);
-		}
-
-		return axolotlMessage;
-	}
+	boolean hasPendingKeyFetches(Account account, Contact contact);
 
 	@Nullable
-	public XmppAxolotlMessage encrypt(Message message) {
-		XmppAxolotlMessage axolotlMessage = buildHeader(message.getContact());
-
-		if (axolotlMessage != null) {
-			final String content;
-			if (message.hasFileOnRemoteHost()) {
-				content = message.getFileParams().url.toString();
-			} else {
-				content = message.getBody();
-			}
-			try {
-				axolotlMessage.encrypt(content);
-			} catch (CryptoFailedException e) {
-				Log.w(Config.LOGTAG, getLogprefix(account) + "Failed to encrypt message: " + e.getMessage());
-				return null;
-			}
-		}
-
-		return axolotlMessage;
-	}
-
-	public void preparePayloadMessage(final Message message, final boolean delay) {
-		executor.execute(new Runnable() {
-			@Override
-			public void run() {
-				XmppAxolotlMessage axolotlMessage = encrypt(message);
-				if (axolotlMessage == null) {
-					mXmppConnectionService.markMessage(message, Message.STATUS_SEND_FAILED);
-					//mXmppConnectionService.updateConversationUi();
-				} else {
-					Log.d(Config.LOGTAG, AxolotlService.getLogprefix(account) + "Generated message, caching: " + message.getUuid());
-					messageCache.put(message.getUuid(), axolotlMessage);
-					mXmppConnectionService.resendMessage(message, delay);
-				}
-			}
-		});
-	}
-
-	public void prepareKeyTransportMessage(final Contact contact, final OnMessageCreatedCallback onMessageCreatedCallback) {
-		executor.execute(new Runnable() {
-			@Override
-			public void run() {
-				XmppAxolotlMessage axolotlMessage = buildHeader(contact);
-				onMessageCreatedCallback.run(axolotlMessage);
-			}
-		});
-	}
-
-	public XmppAxolotlMessage fetchAxolotlMessageFromCache(Message message) {
-		XmppAxolotlMessage axolotlMessage = messageCache.get(message.getUuid());
-		if (axolotlMessage != null) {
-			Log.d(Config.LOGTAG, AxolotlService.getLogprefix(account) + "Cache hit: " + message.getUuid());
-			messageCache.remove(message.getUuid());
-		} else {
-			Log.d(Config.LOGTAG, AxolotlService.getLogprefix(account) + "Cache miss: " + message.getUuid());
-		}
-		return axolotlMessage;
-	}
+	XmppAxolotlMessage encrypt(Message message);
 
-	private XmppAxolotlSession recreateUncachedSession(AxolotlAddress address) {
-		IdentityKey identityKey = axolotlStore.loadSession(address).getSessionState().getRemoteIdentityKey();
-		return (identityKey != null)
-				? new XmppAxolotlSession(account, axolotlStore, address, identityKey)
-				: null;
-	}
+	void preparePayloadMessage(Message message, boolean delay);
 
-	private XmppAxolotlSession getReceivingSession(XmppAxolotlMessage message) {
-		AxolotlAddress senderAddress = new AxolotlAddress(message.getFrom().toString(),
-				message.getSenderDeviceId());
-		XmppAxolotlSession session = sessions.get(senderAddress);
-		if (session == null) {
-			Log.d(Config.LOGTAG, AxolotlService.getLogprefix(account) + "Account: " + account.getJid() + " No axolotl session found while parsing received message " + message);
-			session = recreateUncachedSession(senderAddress);
-			if (session == null) {
-				session = new XmppAxolotlSession(account, axolotlStore, senderAddress);
-			}
-		}
-		return session;
-	}
-
-	public XmppAxolotlMessage.XmppAxolotlPlaintextMessage processReceivingPayloadMessage(XmppAxolotlMessage message) {
-		XmppAxolotlMessage.XmppAxolotlPlaintextMessage plaintextMessage = null;
-
-		XmppAxolotlSession session = getReceivingSession(message);
-		try {
-			plaintextMessage = message.decrypt(session, getOwnDeviceId());
-			Integer preKeyId = session.getPreKeyId();
-			if (preKeyId != null) {
-				publishBundlesIfNeeded(false, false);
-				session.resetPreKeyId();
-			}
-		} catch (CryptoFailedException e) {
-			Log.w(Config.LOGTAG, getLogprefix(account) + "Failed to decrypt message: " + e.getMessage());
-		}
-
-		if (session.isFresh() && plaintextMessage != null) {
-			putFreshSession(session);
-		}
-
-		return plaintextMessage;
-	}
+	void prepareKeyTransportMessage(Contact contact, OnMessageCreatedCallback onMessageCreatedCallback);
 
-	public XmppAxolotlMessage.XmppAxolotlKeyTransportMessage processReceivingKeyTransportMessage(XmppAxolotlMessage message) {
-		XmppAxolotlMessage.XmppAxolotlKeyTransportMessage keyTransportMessage;
+	XmppAxolotlMessage fetchAxolotlMessageFromCache(Message message);
 
-		XmppAxolotlSession session = getReceivingSession(message);
-		keyTransportMessage = message.getParameters(session, getOwnDeviceId());
+	XmppAxolotlMessage.XmppAxolotlPlaintextMessage processReceivingPayloadMessage(XmppAxolotlMessage message);
 
-		if (session.isFresh() && keyTransportMessage != null) {
-			putFreshSession(session);
-		}
-
-		return keyTransportMessage;
-	}
-
-	private void putFreshSession(XmppAxolotlSession session) {
-		Log.d(Config.LOGTAG,"put fresh session");
-		sessions.put(session);
-		if (Config.X509_VERIFICATION) {
-			if (session.getIdentityKey() != null) {
-				verifySessionWithPEP(session);
-			} else {
-				Log.e(Config.LOGTAG,account.getJid().toBareJid()+": identity key was empty after reloading for x509 verification");
-			}
-		}
-	}
+	XmppAxolotlMessage.XmppAxolotlKeyTransportMessage processReceivingKeyTransportMessage(XmppAxolotlMessage message);
 }
diff --git a/src/main/java/eu/siacs/conversations/crypto/axolotl/AxolotlServiceImpl.java b/src/main/java/eu/siacs/conversations/crypto/axolotl/AxolotlServiceImpl.java
new file mode 100644
index 00000000..27d50dbb
--- /dev/null
+++ b/src/main/java/eu/siacs/conversations/crypto/axolotl/AxolotlServiceImpl.java
@@ -0,0 +1,1022 @@
+package eu.siacs.conversations.crypto.axolotl;
+
+import android.os.Bundle;
+import android.security.KeyChain;
+import android.support.annotation.NonNull;
+import android.support.annotation.Nullable;
+import android.util.Log;
+import android.util.Pair;
+
+import org.bouncycastle.jce.provider.BouncyCastleProvider;
+import org.whispersystems.libaxolotl.AxolotlAddress;
+import org.whispersystems.libaxolotl.IdentityKey;
+import org.whispersystems.libaxolotl.IdentityKeyPair;
+import org.whispersystems.libaxolotl.InvalidKeyException;
+import org.whispersystems.libaxolotl.InvalidKeyIdException;
+import org.whispersystems.libaxolotl.SessionBuilder;
+import org.whispersystems.libaxolotl.UntrustedIdentityException;
+import org.whispersystems.libaxolotl.ecc.ECPublicKey;
+import org.whispersystems.libaxolotl.state.PreKeyBundle;
+import org.whispersystems.libaxolotl.state.PreKeyRecord;
+import org.whispersystems.libaxolotl.state.SignedPreKeyRecord;
+import org.whispersystems.libaxolotl.util.KeyHelper;
+
+import java.security.PrivateKey;
+import java.security.Security;
+import java.security.Signature;
+import java.security.cert.X509Certificate;
+import java.util.Arrays;
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Map;
+import java.util.Random;
+import java.util.Set;
+
+import eu.siacs.conversations.Config;
+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.parser.IqParser;
+import eu.siacs.conversations.services.XmppConnectionService;
+import eu.siacs.conversations.utils.CryptoHelper;
+import eu.siacs.conversations.utils.SerialSingleThreadExecutor;
+import eu.siacs.conversations.xml.Element;
+import eu.siacs.conversations.xmpp.OnAdvancedStreamFeaturesLoaded;
+import eu.siacs.conversations.xmpp.OnIqPacketReceived;
+import eu.siacs.conversations.xmpp.jid.InvalidJidException;
+import eu.siacs.conversations.xmpp.jid.Jid;
+import eu.siacs.conversations.xmpp.stanzas.IqPacket;
+
+public class AxolotlServiceImpl implements AxolotlService {
+
+	public static final int NUM_KEYS_TO_PUBLISH = 100;
+	public static final int publishTriesThreshold = 3;
+
+	private final Account account;
+	private final XmppConnectionService mXmppConnectionService;
+	private final SQLiteAxolotlStore axolotlStore;
+	private final SessionMap sessions;
+	private final Map<Jid, Set<Integer>> deviceIds;
+	private final Map<String, XmppAxolotlMessage> messageCache;
+	private final FetchStatusMap fetchStatusMap;
+	private final SerialSingleThreadExecutor executor;
+	private int numPublishTriesOnEmptyPep = 0;
+	private boolean pepBroken = false;
+
+	@Override
+	public void onAdvancedStreamFeaturesAvailable(Account account) {
+		if (account.getXmppConnection() != null && account.getXmppConnection().getFeatures().pep()) {
+			publishBundlesIfNeeded(true, false);
+		} else {
+			Log.d(Config.LOGTAG,account.getJid().toBareJid()+": skipping OMEMO initialization");
+		}
+	}
+
+	@Override
+	public boolean fetchMapHasErrors(Contact contact) {
+		Jid jid = contact.getJid().toBareJid();
+		if (deviceIds.get(jid) != null) {
+			for (Integer foreignId : this.deviceIds.get(jid)) {
+				AxolotlAddress address = new AxolotlAddress(jid.toString(), foreignId);
+				if (fetchStatusMap.getAll(address).containsValue(FetchStatus.ERROR)) {
+					return true;
+				}
+			}
+		}
+		return false;
+	}
+
+	private static class AxolotlAddressMap<T> {
+		protected Map<String, Map<Integer, T>> map;
+		protected final Object MAP_LOCK = new Object();
+
+		public AxolotlAddressMap() {
+			this.map = new HashMap<>();
+		}
+
+		public void put(AxolotlAddress address, T value) {
+			synchronized (MAP_LOCK) {
+				Map<Integer, T> devices = map.get(address.getName());
+				if (devices == null) {
+					devices = new HashMap<>();
+					map.put(address.getName(), devices);
+				}
+				devices.put(address.getDeviceId(), value);
+			}
+		}
+
+		public T get(AxolotlAddress address) {
+			synchronized (MAP_LOCK) {
+				Map<Integer, T> devices = map.get(address.getName());
+				if (devices == null) {
+					return null;
+				}
+				return devices.get(address.getDeviceId());
+			}
+		}
+
+		public Map<Integer, T> getAll(AxolotlAddress address) {
+			synchronized (MAP_LOCK) {
+				Map<Integer, T> devices = map.get(address.getName());
+				if (devices == null) {
+					return new HashMap<>();
+				}
+				return devices;
+			}
+		}
+
+		public boolean hasAny(AxolotlAddress address) {
+			synchronized (MAP_LOCK) {
+				Map<Integer, T> devices = map.get(address.getName());
+				return devices != null && !devices.isEmpty();
+			}
+		}
+
+		public void clear() {
+			map.clear();
+		}
+
+	}
+
+	private static class SessionMap extends AxolotlAddressMap<XmppAxolotlSession> {
+		private final XmppConnectionService xmppConnectionService;
+		private final Account account;
+
+		public SessionMap(XmppConnectionService service, SQLiteAxolotlStore store, Account account) {
+			super();
+			this.xmppConnectionService = service;
+			this.account = account;
+			this.fillMap(store);
+		}
+
+		private void putDevicesForJid(String bareJid, List<Integer> deviceIds, SQLiteAxolotlStore store) {
+			for (Integer deviceId : deviceIds) {
+				AxolotlAddress axolotlAddress = new AxolotlAddress(bareJid, deviceId);
+				Log.d(Config.LOGTAG, AxolotlServiceImpl.getLogprefix(account) + "Building session for remote address: " + axolotlAddress.toString());
+				IdentityKey identityKey = store.loadSession(axolotlAddress).getSessionState().getRemoteIdentityKey();
+				if(Config.X509_VERIFICATION) {
+					X509Certificate certificate = store.getFingerprintCertificate(identityKey.getFingerprint().replaceAll("\\s", ""));
+					if (certificate != null) {
+						Bundle information = CryptoHelper.extractCertificateInformation(certificate);
+						try {
+							final String cn = information.getString("subject_cn");
+							final Jid jid = Jid.fromString(bareJid);
+							Log.d(Config.LOGTAG,"setting common name for "+jid+" to "+cn);
+							account.getRoster().getContact(jid).setCommonName(cn);
+						} catch (final InvalidJidException ignored) {
+							//ignored
+						}
+					}
+				}
+				this.put(axolotlAddress, new XmppAxolotlSession(account, store, axolotlAddress, identityKey));
+			}
+		}
+
+		private void fillMap(SQLiteAxolotlStore store) {
+			List<Integer> deviceIds = store.getSubDeviceSessions(account.getJid().toBareJid().toString());
+			putDevicesForJid(account.getJid().toBareJid().toString(), deviceIds, store);
+			for (Contact contact : account.getRoster().getContacts()) {
+				Jid bareJid = contact.getJid().toBareJid();
+				String address = bareJid.toString();
+				deviceIds = store.getSubDeviceSessions(address);
+				putDevicesForJid(address, deviceIds, store);
+			}
+
+		}
+
+		@Override
+		public void put(AxolotlAddress address, XmppAxolotlSession value) {
+			super.put(address, value);
+			value.setNotFresh();
+			xmppConnectionService.syncRosterToDisk(account);
+		}
+
+		public void put(XmppAxolotlSession session) {
+			this.put(session.getRemoteAddress(), session);
+		}
+	}
+
+	private static class FetchStatusMap extends AxolotlAddressMap<FetchStatus> {
+
+	}
+
+	public static String getLogprefix(Account account) {
+		return LOGPREFIX + " (" + account.getJid().toBareJid().toString() + "): ";
+	}
+
+	public AxolotlServiceImpl(Account account, XmppConnectionService connectionService) {
+		if (Security.getProvider("BC") == null) {
+			Security.addProvider(new BouncyCastleProvider());
+		}
+		this.mXmppConnectionService = connectionService;
+		this.account = account;
+		this.axolotlStore = new SQLiteAxolotlStore(this.account, this.mXmppConnectionService);
+		this.deviceIds = new HashMap<>();
+		this.messageCache = new HashMap<>();
+		this.sessions = new SessionMap(mXmppConnectionService, axolotlStore, account);
+		this.fetchStatusMap = new FetchStatusMap();
+		this.executor = new SerialSingleThreadExecutor();
+	}
+
+	@Override
+	public String getOwnFingerprint() {
+		return axolotlStore.getIdentityKeyPair().getPublicKey().getFingerprint().replaceAll("\\s", "");
+	}
+
+	@Override
+	public Set<IdentityKey> getKeysWithTrust(XmppAxolotlSession.Trust trust) {
+		return axolotlStore.getContactKeysWithTrust(account.getJid().toBareJid().toString(), trust);
+	}
+
+	@Override
+	public Set<IdentityKey> getKeysWithTrust(XmppAxolotlSession.Trust trust, Contact contact) {
+		return axolotlStore.getContactKeysWithTrust(contact.getJid().toBareJid().toString(), trust);
+	}
+
+	@Override
+	public long getNumTrustedKeys(Contact contact) {
+		return axolotlStore.getContactNumTrustedKeys(contact.getJid().toBareJid().toString());
+	}
+
+	private AxolotlAddress getAddressForJid(Jid jid) {
+		return new AxolotlAddress(jid.toString(), 0);
+	}
+
+	private Set<XmppAxolotlSession> findOwnSessions() {
+		AxolotlAddress ownAddress = getAddressForJid(account.getJid().toBareJid());
+		return new HashSet<>(this.sessions.getAll(ownAddress).values());
+	}
+
+	private Set<XmppAxolotlSession> findSessionsforContact(Contact contact) {
+		AxolotlAddress contactAddress = getAddressForJid(contact.getJid());
+		return new HashSet<>(this.sessions.getAll(contactAddress).values());
+	}
+
+	@Override
+	public Set<String> getFingerprintsForOwnSessions() {
+		Set<String> fingerprints = new HashSet<>();
+		for (XmppAxolotlSession session : findOwnSessions()) {
+			fingerprints.add(session.getFingerprint());
+		}
+		return fingerprints;
+	}
+
+	@Override
+	public Set<String> getFingerprintsForContact(final Contact contact) {
+		Set<String> fingerprints = new HashSet<>();
+		for (XmppAxolotlSession session : findSessionsforContact(contact)) {
+			fingerprints.add(session.getFingerprint());
+		}
+		return fingerprints;
+	}
+
+	private boolean hasAny(Contact contact) {
+		AxolotlAddress contactAddress = getAddressForJid(contact.getJid());
+		return sessions.hasAny(contactAddress);
+	}
+
+	@Override
+	public boolean isPepBroken() {
+		return this.pepBroken;
+	}
+
+	@Override
+	public void regenerateKeys(boolean wipeOther) {
+		axolotlStore.regenerate();
+		sessions.clear();
+		fetchStatusMap.clear();
+		publishBundlesIfNeeded(true, wipeOther);
+	}
+
+	@Override
+	public int getOwnDeviceId() {
+		return axolotlStore.getLocalRegistrationId();
+	}
+
+	@Override
+	public Set<Integer> getOwnDeviceIds() {
+		return this.deviceIds.get(account.getJid().toBareJid());
+	}
+
+	private void setTrustOnSessions(final Jid jid, @NonNull final Set<Integer> deviceIds,
+	                                final XmppAxolotlSession.Trust from,
+	                                final XmppAxolotlSession.Trust to) {
+		for (Integer deviceId : deviceIds) {
+			AxolotlAddress address = new AxolotlAddress(jid.toBareJid().toString(), deviceId);
+			XmppAxolotlSession session = sessions.get(address);
+			if (session != null && session.getFingerprint() != null
+					&& session.getTrust() == from) {
+				session.setTrust(to);
+			}
+		}
+	}
+
+	@Override
+	public void registerDevices(final Jid jid, @NonNull final Set<Integer> deviceIds) {
+		if (jid.toBareJid().equals(account.getJid().toBareJid())) {
+			if (!deviceIds.isEmpty()) {
+				Log.d(Config.LOGTAG, getLogprefix(account) + "Received non-empty own device list. Resetting publish attemps and pepBroken status.");
+				pepBroken = false;
+				numPublishTriesOnEmptyPep = 0;
+			}
+			if (deviceIds.contains(getOwnDeviceId())) {
+				deviceIds.remove(getOwnDeviceId());
+			} else {
+				publishOwnDeviceId(deviceIds);
+			}
+			for (Integer deviceId : deviceIds) {
+				AxolotlAddress ownDeviceAddress = new AxolotlAddress(jid.toBareJid().toString(), deviceId);
+				if (sessions.get(ownDeviceAddress) == null) {
+					buildSessionFromPEP(ownDeviceAddress);
+				}
+			}
+		}
+		Set<Integer> expiredDevices = new HashSet<>(axolotlStore.getSubDeviceSessions(jid.toBareJid().toString()));
+		expiredDevices.removeAll(deviceIds);
+		setTrustOnSessions(jid, expiredDevices, XmppAxolotlSession.Trust.TRUSTED,
+				XmppAxolotlSession.Trust.INACTIVE_TRUSTED);
+		setTrustOnSessions(jid, expiredDevices, XmppAxolotlSession.Trust.TRUSTED_X509,
+				XmppAxolotlSession.Trust.INACTIVE_TRUSTED_X509);
+		setTrustOnSessions(jid, expiredDevices, XmppAxolotlSession.Trust.UNDECIDED,
+				XmppAxolotlSession.Trust.INACTIVE_UNDECIDED);
+		setTrustOnSessions(jid, expiredDevices, XmppAxolotlSession.Trust.UNTRUSTED,
+				XmppAxolotlSession.Trust.INACTIVE_UNTRUSTED);
+		Set<Integer> newDevices = new HashSet<>(deviceIds);
+		setTrustOnSessions(jid, newDevices, XmppAxolotlSession.Trust.INACTIVE_TRUSTED,
+				XmppAxolotlSession.Trust.TRUSTED);
+		setTrustOnSessions(jid, newDevices, XmppAxolotlSession.Trust.INACTIVE_TRUSTED_X509,
+				XmppAxolotlSession.Trust.TRUSTED_X509);
+		setTrustOnSessions(jid, newDevices, XmppAxolotlSession.Trust.INACTIVE_UNDECIDED,
+				XmppAxolotlSession.Trust.UNDECIDED);
+		setTrustOnSessions(jid, newDevices, XmppAxolotlSession.Trust.INACTIVE_UNTRUSTED,
+				XmppAxolotlSession.Trust.UNTRUSTED);
+		this.deviceIds.put(jid, deviceIds);
+		mXmppConnectionService.keyStatusUpdated(null);
+	}
+
+	@Override
+	public void wipeOtherPepDevices() {
+		if (pepBroken) {
+			Log.d(Config.LOGTAG, getLogprefix(account) + "wipeOtherPepDevices called, but PEP is broken. Ignoring... ");
+			return;
+		}
+		Set<Integer> deviceIds = new HashSet<>();
+		deviceIds.add(getOwnDeviceId());
+		IqPacket publish = mXmppConnectionService.getIqGenerator().publishDeviceIds(deviceIds);
+		Log.d(Config.LOGTAG, AxolotlServiceImpl.getLogprefix(account) + "Wiping all other devices from Pep:" + publish);
+		mXmppConnectionService.sendIqPacket(account, publish, new OnIqPacketReceived() {
+			@Override
+			public void onIqPacketReceived(Account account, IqPacket packet) {
+				// TODO: implement this!
+			}
+		});
+	}
+
+	@Override
+	public void purgeKey(final String fingerprint) {
+		axolotlStore.setFingerprintTrust(fingerprint.replaceAll("\\s", ""), XmppAxolotlSession.Trust.COMPROMISED);
+	}
+
+	@Override
+	public void publishOwnDeviceIdIfNeeded() {
+		if (pepBroken) {
+			Log.d(Config.LOGTAG, getLogprefix(account) + "publishOwnDeviceIdIfNeeded called, but PEP is broken. Ignoring... ");
+			return;
+		}
+		IqPacket packet = mXmppConnectionService.getIqGenerator().retrieveDeviceIds(account.getJid().toBareJid());
+		mXmppConnectionService.sendIqPacket(account, packet, new OnIqPacketReceived() {
+			@Override
+			public void onIqPacketReceived(Account account, IqPacket packet) {
+				if (packet.getType() == IqPacket.TYPE.TIMEOUT) {
+					Log.d(Config.LOGTAG, getLogprefix(account) + "Timeout received while retrieving own Device Ids.");
+				} else {
+					Element item = mXmppConnectionService.getIqParser().getItem(packet);
+					Set<Integer> deviceIds = mXmppConnectionService.getIqParser().deviceIds(item);
+					if (!deviceIds.contains(getOwnDeviceId())) {
+						publishOwnDeviceId(deviceIds);
+					}
+				}
+			}
+		});
+	}
+
+	@Override
+	public void publishOwnDeviceId(Set<Integer> deviceIds) {
+		Set<Integer> deviceIdsCopy = new HashSet<>(deviceIds);
+		if (!deviceIdsCopy.contains(getOwnDeviceId())) {
+			Log.d(Config.LOGTAG, AxolotlServiceImpl.getLogprefix(account) + "Own device " + getOwnDeviceId() + " not in PEP devicelist.");
+			if (deviceIdsCopy.isEmpty()) {
+				if (numPublishTriesOnEmptyPep >= publishTriesThreshold) {
+					Log.w(Config.LOGTAG, getLogprefix(account) + "Own device publish attempt threshold exceeded, aborting...");
+					pepBroken = true;
+					return;
+				} else {
+					numPublishTriesOnEmptyPep++;
+					Log.w(Config.LOGTAG, getLogprefix(account) + "Own device list empty, attempting to publish (try " + numPublishTriesOnEmptyPep + ")");
+				}
+			} else {
+				numPublishTriesOnEmptyPep = 0;
+			}
+			deviceIdsCopy.add(getOwnDeviceId());
+			IqPacket publish = mXmppConnectionService.getIqGenerator().publishDeviceIds(deviceIdsCopy);
+			mXmppConnectionService.sendIqPacket(account, publish, new OnIqPacketReceived() {
+				@Override
+				public void onIqPacketReceived(Account account, IqPacket packet) {
+					if (packet.getType() != IqPacket.TYPE.RESULT) {
+						Log.d(Config.LOGTAG, getLogprefix(account) + "Error received while publishing own device id" + packet.findChild("error"));
+					}
+				}
+			});
+		}
+	}
+
+	@Override
+	public void publishDeviceVerificationAndBundle(final SignedPreKeyRecord signedPreKeyRecord,
+												   final Set<PreKeyRecord> preKeyRecords,
+												   final boolean announceAfter,
+												   final boolean wipe) {
+		try {
+			IdentityKey axolotlPublicKey = axolotlStore.getIdentityKeyPair().getPublicKey();
+			PrivateKey x509PrivateKey = KeyChain.getPrivateKey(mXmppConnectionService, account.getPrivateKeyAlias());
+			X509Certificate[] chain = KeyChain.getCertificateChain(mXmppConnectionService, account.getPrivateKeyAlias());
+			Signature verifier = Signature.getInstance("sha256WithRSA");
+			verifier.initSign(x509PrivateKey,mXmppConnectionService.getRNG());
+			verifier.update(axolotlPublicKey.serialize());
+			byte[] signature = verifier.sign();
+			IqPacket packet = mXmppConnectionService.getIqGenerator().publishVerification(signature, chain, getOwnDeviceId());
+			Log.d(Config.LOGTAG, AxolotlServiceImpl.getLogprefix(account) + ": publish verification for device "+getOwnDeviceId());
+			mXmppConnectionService.sendIqPacket(account, packet, new OnIqPacketReceived() {
+				@Override
+				public void onIqPacketReceived(Account account, IqPacket packet) {
+					publishDeviceBundle(signedPreKeyRecord, preKeyRecords, announceAfter, wipe);
+				}
+			});
+		} catch (Exception  e) {
+			e.printStackTrace();
+		}
+	}
+
+	@Override
+	public void publishBundlesIfNeeded(final boolean announce, final boolean wipe) {
+		if (pepBroken) {
+			Log.d(Config.LOGTAG, getLogprefix(account) + "publishBundlesIfNeeded called, but PEP is broken. Ignoring... ");
+			return;
+		}
+		IqPacket packet = mXmppConnectionService.getIqGenerator().retrieveBundlesForDevice(account.getJid().toBareJid(), getOwnDeviceId());
+		mXmppConnectionService.sendIqPacket(account, packet, new OnIqPacketReceived() {
+			@Override
+			public void onIqPacketReceived(Account account, IqPacket packet) {
+
+				if (packet.getType() == IqPacket.TYPE.TIMEOUT) {
+					return; //ignore timeout. do nothing
+				}
+
+				if (packet.getType() == IqPacket.TYPE.ERROR) {
+					Element error = packet.findChild("error");
+					if (error == null || !error.hasChild("item-not-found")) {
+						pepBroken = true;
+						Log.w(Config.LOGTAG, AxolotlServiceImpl.getLogprefix(account) + "request for device bundles came back with something other than item-not-found" + packet);
+						return;
+					}
+				}
+
+				PreKeyBundle bundle = mXmppConnectionService.getIqParser().bundle(packet);
+				Map<Integer, ECPublicKey> keys = mXmppConnectionService.getIqParser().preKeyPublics(packet);
+				boolean flush = false;
+				if (bundle == null) {
+					Log.w(Config.LOGTAG, AxolotlServiceImpl.getLogprefix(account) + "Received invalid bundle:" + packet);
+					bundle = new PreKeyBundle(-1, -1, -1, null, -1, null, null, null);
+					flush = true;
+				}
+				if (keys == null) {
+					Log.w(Config.LOGTAG, AxolotlServiceImpl.getLogprefix(account) + "Received invalid prekeys:" + packet);
+				}
+				try {
+					boolean changed = false;
+					// Validate IdentityKey
+					IdentityKeyPair identityKeyPair = axolotlStore.getIdentityKeyPair();
+					if (flush || !identityKeyPair.getPublicKey().equals(bundle.getIdentityKey())) {
+						Log.i(Config.LOGTAG, AxolotlServiceImpl.getLogprefix(account) + "Adding own IdentityKey " + identityKeyPair.getPublicKey() + " to PEP.");
+						changed = true;
+					}
+
+					// Validate signedPreKeyRecord + ID
+					SignedPreKeyRecord signedPreKeyRecord;
+					int numSignedPreKeys = axolotlStore.loadSignedPreKeys().size();
+					try {
+						signedPreKeyRecord = axolotlStore.loadSignedPreKey(bundle.getSignedPreKeyId());
+						if (flush
+								|| !bundle.getSignedPreKey().equals(signedPreKeyRecord.getKeyPair().getPublicKey())
+								|| !Arrays.equals(bundle.getSignedPreKeySignature(), signedPreKeyRecord.getSignature())) {
+							Log.i(Config.LOGTAG, AxolotlServiceImpl.getLogprefix(account) + "Adding new signedPreKey with ID " + (numSignedPreKeys + 1) + " to PEP.");
+							signedPreKeyRecord = KeyHelper.generateSignedPreKey(identityKeyPair, numSignedPreKeys + 1);
+							axolotlStore.storeSignedPreKey(signedPreKeyRecord.getId(), signedPreKeyRecord);
+							changed = true;
+						}
+					} catch (InvalidKeyIdException e) {
+						Log.i(Config.LOGTAG, AxolotlServiceImpl.getLogprefix(account) + "Adding new signedPreKey with ID " + (numSignedPreKeys + 1) + " to PEP.");
+						signedPreKeyRecord = KeyHelper.generateSignedPreKey(identityKeyPair, numSignedPreKeys + 1);
+						axolotlStore.storeSignedPreKey(signedPreKeyRecord.getId(), signedPreKeyRecord);
+						changed = true;
+					}
+
+					// Validate PreKeys
+					Set<PreKeyRecord> preKeyRecords = new HashSet<>();
+					if (keys != null) {
+						for (Integer id : keys.keySet()) {
+							try {
+								PreKeyRecord preKeyRecord = axolotlStore.loadPreKey(id);
+								if (preKeyRecord.getKeyPair().getPublicKey().equals(keys.get(id))) {
+									preKeyRecords.add(preKeyRecord);
+								}
+							} catch (InvalidKeyIdException ignored) {
+							}
+						}
+					}
+					int newKeys = NUM_KEYS_TO_PUBLISH - preKeyRecords.size();
+					if (newKeys > 0) {
+						List<PreKeyRecord> newRecords = KeyHelper.generatePreKeys(
+								axolotlStore.getCurrentPreKeyId() + 1, newKeys);
+						preKeyRecords.addAll(newRecords);
+						for (PreKeyRecord record : newRecords) {
+							axolotlStore.storePreKey(record.getId(), record);
+						}
+						changed = true;
+						Log.i(Config.LOGTAG, AxolotlServiceImpl.getLogprefix(account) + "Adding " + newKeys + " new preKeys to PEP.");
+					}
+
+
+					if (changed) {
+						if (account.getPrivateKeyAlias() != null && Config.X509_VERIFICATION) {
+							mXmppConnectionService.publishDisplayName(account);
+							publishDeviceVerificationAndBundle(signedPreKeyRecord, preKeyRecords, announce, wipe);
+						} else {
+							publishDeviceBundle(signedPreKeyRecord, preKeyRecords, announce, wipe);
+						}
+					} else {
+						Log.d(Config.LOGTAG, getLogprefix(account) + "Bundle " + getOwnDeviceId() + " in PEP was current");
+						if (wipe) {
+							wipeOtherPepDevices();
+						} else if (announce) {
+							Log.d(Config.LOGTAG, getLogprefix(account) + "Announcing device " + getOwnDeviceId());
+							publishOwnDeviceIdIfNeeded();
+						}
+					}
+				} catch (InvalidKeyException e) {
+					Log.e(Config.LOGTAG, AxolotlServiceImpl.getLogprefix(account) + "Failed to publish bundle " + getOwnDeviceId() + ", reason: " + e.getMessage());
+				}
+			}
+		});
+	}
+
+	private void publishDeviceBundle(SignedPreKeyRecord signedPreKeyRecord,
+									 Set<PreKeyRecord> preKeyRecords,
+									 final boolean announceAfter,
+									 final boolean wipe) {
+		IqPacket publish = mXmppConnectionService.getIqGenerator().publishBundles(
+				signedPreKeyRecord, axolotlStore.getIdentityKeyPair().getPublicKey(),
+				preKeyRecords, getOwnDeviceId());
+		Log.d(Config.LOGTAG, AxolotlServiceImpl.getLogprefix(account) + ": Bundle " + getOwnDeviceId() + " in PEP not current. Publishing: " + publish);
+		mXmppConnectionService.sendIqPacket(account, publish, new OnIqPacketReceived() {
+			@Override
+			public void onIqPacketReceived(Account account, IqPacket packet) {
+				if (packet.getType() == IqPacket.TYPE.RESULT) {
+					Log.d(Config.LOGTAG, AxolotlServiceImpl.getLogprefix(account) + "Successfully published bundle. ");
+					if (wipe) {
+						wipeOtherPepDevices();
+					} else if (announceAfter) {
+						Log.d(Config.LOGTAG, getLogprefix(account) + "Announcing device " + getOwnDeviceId());
+						publishOwnDeviceIdIfNeeded();
+					}
+				} else {
+					Log.d(Config.LOGTAG, getLogprefix(account) + "Error received while publishing bundle: " + packet.findChild("error"));
+				}
+			}
+		});
+	}
+
+	@Override
+	public boolean isContactAxolotlCapable(Contact contact) {
+		Jid jid = contact.getJid().toBareJid();
+		return hasAny(contact) ||
+				(deviceIds.containsKey(jid) && !deviceIds.get(jid).isEmpty());
+	}
+
+	@Override
+	public XmppAxolotlSession.Trust getFingerprintTrust(String fingerprint) {
+		return axolotlStore.getFingerprintTrust(fingerprint);
+	}
+
+	@Override
+	public X509Certificate getFingerprintCertificate(String fingerprint) {
+		return axolotlStore.getFingerprintCertificate(fingerprint);
+	}
+
+	@Override
+	public void setFingerprintTrust(String fingerprint, XmppAxolotlSession.Trust trust) {
+		axolotlStore.setFingerprintTrust(fingerprint, trust);
+	}
+
+	private void verifySessionWithPEP(final XmppAxolotlSession session) {
+		Log.d(Config.LOGTAG, "trying to verify fresh session (" + session.getRemoteAddress().getName() + ") with pep");
+		final AxolotlAddress address = session.getRemoteAddress();
+		final IdentityKey identityKey = session.getIdentityKey();
+		try {
+			IqPacket packet = mXmppConnectionService.getIqGenerator().retrieveVerificationForDevice(Jid.fromString(address.getName()), address.getDeviceId());
+			mXmppConnectionService.sendIqPacket(account, packet, new OnIqPacketReceived() {
+				@Override
+				public void onIqPacketReceived(Account account, IqPacket packet) {
+					Pair<X509Certificate[],byte[]> verification = mXmppConnectionService.getIqParser().verification(packet);
+					if (verification != null) {
+						try {
+							Signature verifier = Signature.getInstance("sha256WithRSA");
+							verifier.initVerify(verification.first[0]);
+							verifier.update(identityKey.serialize());
+							if (verifier.verify(verification.second)) {
+								try {
+									mXmppConnectionService.getMemorizingTrustManager().getNonInteractive().checkClientTrusted(verification.first, "RSA");
+									String fingerprint = session.getFingerprint();
+									Log.d(Config.LOGTAG, "verified session with x.509 signature. fingerprint was: "+fingerprint);
+									setFingerprintTrust(fingerprint, XmppAxolotlSession.Trust.TRUSTED_X509);
+									axolotlStore.setFingerprintCertificate(fingerprint, verification.first[0]);
+									fetchStatusMap.put(address, FetchStatus.SUCCESS_VERIFIED);
+									Bundle information = CryptoHelper.extractCertificateInformation(verification.first[0]);
+									try {
+										final String cn = information.getString("subject_cn");
+										final Jid jid = Jid.fromString(address.getName());
+										Log.d(Config.LOGTAG,"setting common name for "+jid+" to "+cn);
+										account.getRoster().getContact(jid).setCommonName(cn);
+									} catch (final InvalidJidException ignored) {
+										//ignored
+									}
+									finishBuildingSessionsFromPEP(address);
+									return;
+								} catch (Exception e) {
+									Log.d(Config.LOGTAG,"could not verify certificate");
+								}
+							}
+						} catch (Exception e) {
+							Log.d(Config.LOGTAG, "error during verification " + e.getMessage());
+						}
+					} else {
+						Log.d(Config.LOGTAG,"no verification found");
+					}
+					fetchStatusMap.put(address, FetchStatus.SUCCESS);
+					finishBuildingSessionsFromPEP(address);
+				}
+			});
+		} catch (InvalidJidException e) {
+			fetchStatusMap.put(address, FetchStatus.SUCCESS);
+			finishBuildingSessionsFromPEP(address);
+		}
+	}
+
+	private void finishBuildingSessionsFromPEP(final AxolotlAddress address) {
+		AxolotlAddress ownAddress = new AxolotlAddress(account.getJid().toBareJid().toString(), 0);
+		if (!fetchStatusMap.getAll(ownAddress).containsValue(FetchStatus.PENDING)
+				&& !fetchStatusMap.getAll(address).containsValue(FetchStatus.PENDING)) {
+			FetchStatus report = null;
+			if (fetchStatusMap.getAll(ownAddress).containsValue(FetchStatus.SUCCESS_VERIFIED)
+					| fetchStatusMap.getAll(address).containsValue(FetchStatus.SUCCESS_VERIFIED)) {
+				report = FetchStatus.SUCCESS_VERIFIED;
+			} else if (fetchStatusMap.getAll(ownAddress).containsValue(FetchStatus.ERROR)
+					|| fetchStatusMap.getAll(address).containsValue(FetchStatus.ERROR)) {
+				report = FetchStatus.ERROR;
+			}
+			mXmppConnectionService.keyStatusUpdated(report);
+		}
+	}
+
+	private void buildSessionFromPEP(final AxolotlAddress address) {
+		Log.i(Config.LOGTAG, AxolotlServiceImpl.getLogprefix(account) + "Building new sesstion for " + address.toString());
+		if (address.getDeviceId() == getOwnDeviceId()) {
+			throw new AssertionError("We should NEVER build a session with ourselves. What happened here?!");
+		}
+
+		try {
+			IqPacket bundlesPacket = mXmppConnectionService.getIqGenerator().retrieveBundlesForDevice(
+					Jid.fromString(address.getName()), address.getDeviceId());
+			Log.d(Config.LOGTAG, AxolotlServiceImpl.getLogprefix(account) + "Retrieving bundle: " + bundlesPacket);
+			mXmppConnectionService.sendIqPacket(account, bundlesPacket, new OnIqPacketReceived() {
+
+				@Override
+				public void onIqPacketReceived(Account account, IqPacket packet) {
+					if (packet.getType() == IqPacket.TYPE.TIMEOUT) {
+						fetchStatusMap.put(address, FetchStatus.TIMEOUT);
+					} else if (packet.getType() == IqPacket.TYPE.RESULT) {
+						Log.d(Config.LOGTAG, AxolotlServiceImpl.getLogprefix(account) + "Received preKey IQ packet, processing...");
+						final IqParser parser = mXmppConnectionService.getIqParser();
+						final List<PreKeyBundle> preKeyBundleList = parser.preKeys(packet);
+						final PreKeyBundle bundle = parser.bundle(packet);
+						if (preKeyBundleList.isEmpty() || bundle == null) {
+							Log.e(Config.LOGTAG, AxolotlServiceImpl.getLogprefix(account) + "preKey IQ packet invalid: " + packet);
+							fetchStatusMap.put(address, FetchStatus.ERROR);
+							finishBuildingSessionsFromPEP(address);
+							return;
+						}
+						Random random = new Random();
+						final PreKeyBundle preKey = preKeyBundleList.get(random.nextInt(preKeyBundleList.size()));
+						if (preKey == null) {
+							//should never happen
+							fetchStatusMap.put(address, FetchStatus.ERROR);
+							finishBuildingSessionsFromPEP(address);
+							return;
+						}
+
+						final PreKeyBundle preKeyBundle = new PreKeyBundle(0, address.getDeviceId(),
+								preKey.getPreKeyId(), preKey.getPreKey(),
+								bundle.getSignedPreKeyId(), bundle.getSignedPreKey(),
+								bundle.getSignedPreKeySignature(), bundle.getIdentityKey());
+
+						try {
+							SessionBuilder builder = new SessionBuilder(axolotlStore, address);
+							builder.process(preKeyBundle);
+							XmppAxolotlSession session = new XmppAxolotlSession(account, axolotlStore, address, bundle.getIdentityKey());
+							sessions.put(address, session);
+							if (Config.X509_VERIFICATION) {
+								verifySessionWithPEP(session);
+							} else {
+								fetchStatusMap.put(address, FetchStatus.SUCCESS);
+								finishBuildingSessionsFromPEP(address);
+							}
+						} catch (UntrustedIdentityException | InvalidKeyException e) {
+							Log.e(Config.LOGTAG, AxolotlServiceImpl.getLogprefix(account) + "Error building session for " + address + ": "
+									+ e.getClass().getName() + ", " + e.getMessage());
+							fetchStatusMap.put(address, FetchStatus.ERROR);
+							finishBuildingSessionsFromPEP(address);
+						}
+					} else {
+						fetchStatusMap.put(address, FetchStatus.ERROR);
+						Log.d(Config.LOGTAG, getLogprefix(account) + "Error received while building session:" + packet.findChild("error"));
+						finishBuildingSessionsFromPEP(address);
+					}
+				}
+			});
+		} catch (InvalidJidException e) {
+			Log.e(Config.LOGTAG, AxolotlServiceImpl.getLogprefix(account) + "Got address with invalid jid: " + address.getName());
+		}
+	}
+
+	@Override
+	public Set<AxolotlAddress> findDevicesWithoutSession(final Conversation conversation) {
+		return findDevicesWithoutSession(conversation.getContact().getJid().toBareJid());
+	}
+
+	@Override
+	public Set<AxolotlAddress> findDevicesWithoutSession(final Jid contactJid) {
+		Log.d(Config.LOGTAG, AxolotlServiceImpl.getLogprefix(account) + "Finding devices without session for " + contactJid);
+		Set<AxolotlAddress> addresses = new HashSet<>();
+		if (deviceIds.get(contactJid) != null) {
+			for (Integer foreignId : this.deviceIds.get(contactJid)) {
+				AxolotlAddress address = new AxolotlAddress(contactJid.toString(), foreignId);
+				if (sessions.get(address) == null) {
+					IdentityKey identityKey = axolotlStore.loadSession(address).getSessionState().getRemoteIdentityKey();
+					if (identityKey != null) {
+						Log.d(Config.LOGTAG, AxolotlServiceImpl.getLogprefix(account) + "Already have session for " + address.toString() + ", adding to cache...");
+						XmppAxolotlSession session = new XmppAxolotlSession(account, axolotlStore, address, identityKey);
+						sessions.put(address, session);
+					} else {
+						Log.d(Config.LOGTAG, AxolotlServiceImpl.getLogprefix(account) + "Found device " + contactJid + ":" + foreignId);
+						if (fetchStatusMap.get(address) != FetchStatus.ERROR) {
+							addresses.add(address);
+						} else {
+							Log.d(Config.LOGTAG,getLogprefix(account)+"skipping over "+address+" because it's broken");
+						}
+					}
+				}
+			}
+		} else {
+			Log.w(Config.LOGTAG, AxolotlServiceImpl.getLogprefix(account) + "Have no target devices in PEP!");
+		}
+		if (deviceIds.get(account.getJid().toBareJid()) != null) {
+			for (Integer ownId : this.deviceIds.get(account.getJid().toBareJid())) {
+				AxolotlAddress address = new AxolotlAddress(account.getJid().toBareJid().toString(), ownId);
+				if (sessions.get(address) == null) {
+					IdentityKey identityKey = axolotlStore.loadSession(address).getSessionState().getRemoteIdentityKey();
+					if (identityKey != null) {
+						Log.d(Config.LOGTAG, AxolotlServiceImpl.getLogprefix(account) + "Already have session for " + address.toString() + ", adding to cache...");
+						XmppAxolotlSession session = new XmppAxolotlSession(account, axolotlStore, address, identityKey);
+						sessions.put(address, session);
+					} else {
+						Log.d(Config.LOGTAG, AxolotlServiceImpl.getLogprefix(account) + "Found device " + account.getJid().toBareJid() + ":" + ownId);
+						if (fetchStatusMap.get(address) != FetchStatus.ERROR) {
+							addresses.add(address);
+						} else {
+							Log.d(Config.LOGTAG,getLogprefix(account)+"skipping over "+address+" because it's broken");
+						}
+					}
+				}
+			}
+		}
+
+		return addresses;
+	}
+
+	@Override
+	public boolean createSessionsIfNeeded(final Conversation conversation) {
+		Log.i(Config.LOGTAG, AxolotlServiceImpl.getLogprefix(account) + "Creating axolotl sessions if needed...");
+		boolean newSessions = false;
+		Set<AxolotlAddress> addresses = findDevicesWithoutSession(conversation);
+		for (AxolotlAddress address : addresses) {
+			Log.d(Config.LOGTAG, AxolotlServiceImpl.getLogprefix(account) + "Processing device: " + address.toString());
+			FetchStatus status = fetchStatusMap.get(address);
+			if (status == null || status == FetchStatus.TIMEOUT) {
+				fetchStatusMap.put(address, FetchStatus.PENDING);
+				this.buildSessionFromPEP(address);
+				newSessions = true;
+			} else if (status == FetchStatus.PENDING) {
+				newSessions = true;
+			} else {
+				Log.d(Config.LOGTAG, AxolotlServiceImpl.getLogprefix(account) + "Already fetching bundle for " + address.toString());
+			}
+		}
+
+		return newSessions;
+	}
+
+	@Override
+	public boolean trustedSessionVerified(final Conversation conversation) {
+		Set<XmppAxolotlSession> sessions = findSessionsforContact(conversation.getContact());
+		sessions.addAll(findOwnSessions());
+		boolean verified = false;
+		for(XmppAxolotlSession session : sessions) {
+			if (session.getTrust().trusted()) {
+				if (session.getTrust() == XmppAxolotlSession.Trust.TRUSTED_X509) {
+					verified = true;
+				} else {
+					return false;
+				}
+			}
+		}
+		return verified;
+	}
+
+	@Override
+	public boolean hasPendingKeyFetches(Account account, Contact contact) {
+		AxolotlAddress ownAddress = new AxolotlAddress(account.getJid().toBareJid().toString(), 0);
+		AxolotlAddress foreignAddress = new AxolotlAddress(contact.getJid().toBareJid().toString(), 0);
+		return fetchStatusMap.getAll(ownAddress).containsValue(FetchStatus.PENDING)
+				|| fetchStatusMap.getAll(foreignAddress).containsValue(FetchStatus.PENDING);
+
+	}
+
+	@Nullable
+	private XmppAxolotlMessage buildHeader(Contact contact) {
+		final XmppAxolotlMessage axolotlMessage = new XmppAxolotlMessage(
+				contact.getJid().toBareJid(), getOwnDeviceId());
+
+		Set<XmppAxolotlSession> contactSessions = findSessionsforContact(contact);
+		Set<XmppAxolotlSession> ownSessions = findOwnSessions();
+		if (contactSessions.isEmpty()) {
+			return null;
+		}
+		Log.d(Config.LOGTAG, AxolotlServiceImpl.getLogprefix(account) + "Building axolotl foreign keyElements...");
+		for (XmppAxolotlSession session : contactSessions) {
+			Log.v(Config.LOGTAG, AxolotlServiceImpl.getLogprefix(account) + session.getRemoteAddress().toString());
+			axolotlMessage.addDevice(session);
+		}
+		Log.d(Config.LOGTAG, AxolotlServiceImpl.getLogprefix(account) + "Building axolotl own keyElements...");
+		for (XmppAxolotlSession session : ownSessions) {
+			Log.v(Config.LOGTAG, AxolotlServiceImpl.getLogprefix(account) + session.getRemoteAddress().toString());
+			axolotlMessage.addDevice(session);
+		}
+
+		return axolotlMessage;
+	}
+
+	@Override
+	@Nullable
+	public XmppAxolotlMessage encrypt(Message message) {
+		XmppAxolotlMessage axolotlMessage = buildHeader(message.getContact());
+
+		if (axolotlMessage != null) {
+			final String content;
+			if (message.hasFileOnRemoteHost()) {
+				content = message.getFileParams().url.toString();
+			} else {
+				content = message.getBody();
+			}
+			try {
+				axolotlMessage.encrypt(content);
+			} catch (CryptoFailedException e) {
+				Log.w(Config.LOGTAG, getLogprefix(account) + "Failed to encrypt message: " + e.getMessage());
+				return null;
+			}
+		}
+
+		return axolotlMessage;
+	}
+
+	@Override
+	public void preparePayloadMessage(final Message message, final boolean delay) {
+		executor.execute(new Runnable() {
+			@Override
+			public void run() {
+				XmppAxolotlMessage axolotlMessage = encrypt(message);
+				if (axolotlMessage == null) {
+					mXmppConnectionService.markMessage(message, Message.STATUS_SEND_FAILED);
+					//mXmppConnectionService.updateConversationUi();
+				} else {
+					Log.d(Config.LOGTAG, AxolotlServiceImpl.getLogprefix(account) + "Generated message, caching: " + message.getUuid());
+					messageCache.put(message.getUuid(), axolotlMessage);
+					mXmppConnectionService.resendMessage(message, delay);
+				}
+			}
+		});
+	}
+
+	@Override
+	public void prepareKeyTransportMessage(final Contact contact, final OnMessageCreatedCallback onMessageCreatedCallback) {
+		executor.execute(new Runnable() {
+			@Override
+			public void run() {
+				XmppAxolotlMessage axolotlMessage = buildHeader(contact);
+				onMessageCreatedCallback.run(axolotlMessage);
+			}
+		});
+	}
+
+	@Override
+	public XmppAxolotlMessage fetchAxolotlMessageFromCache(Message message) {
+		XmppAxolotlMessage axolotlMessage = messageCache.get(message.getUuid());
+		if (axolotlMessage != null) {
+			Log.d(Config.LOGTAG, AxolotlServiceImpl.getLogprefix(account) + "Cache hit: " + message.getUuid());
+			messageCache.remove(message.getUuid());
+		} else {
+			Log.d(Config.LOGTAG, AxolotlServiceImpl.getLogprefix(account) + "Cache miss: " + message.getUuid());
+		}
+		return axolotlMessage;
+	}
+
+	private XmppAxolotlSession recreateUncachedSession(AxolotlAddress address) {
+		IdentityKey identityKey = axolotlStore.loadSession(address).getSessionState().getRemoteIdentityKey();
+		return (identityKey != null)
+				? new XmppAxolotlSession(account, axolotlStore, address, identityKey)
+				: null;
+	}
+
+	private XmppAxolotlSession getReceivingSession(XmppAxolotlMessage message) {
+		AxolotlAddress senderAddress = new AxolotlAddress(message.getFrom().toString(),
+				message.getSenderDeviceId());
+		XmppAxolotlSession session = sessions.get(senderAddress);
+		if (session == null) {
+			Log.d(Config.LOGTAG, AxolotlServiceImpl.getLogprefix(account) + "Account: " + account.getJid() + " No axolotl session found while parsing received message " + message);
+			session = recreateUncachedSession(senderAddress);
+			if (session == null) {
+				session = new XmppAxolotlSession(account, axolotlStore, senderAddress);
+			}
+		}
+		return session;
+	}
+
+	@Override
+	public XmppAxolotlMessage.XmppAxolotlPlaintextMessage processReceivingPayloadMessage(XmppAxolotlMessage message) {
+		XmppAxolotlMessage.XmppAxolotlPlaintextMessage plaintextMessage = null;
+
+		XmppAxolotlSession session = getReceivingSession(message);
+		try {
+			plaintextMessage = message.decrypt(session, getOwnDeviceId());
+			Integer preKeyId = session.getPreKeyId();
+			if (preKeyId != null) {
+				publishBundlesIfNeeded(false, false);
+				session.resetPreKeyId();
+			}
+		} catch (CryptoFailedException e) {
+			Log.w(Config.LOGTAG, getLogprefix(account) + "Failed to decrypt message: " + e.getMessage());
+		}
+
+		if (session.isFresh() && plaintextMessage != null) {
+			putFreshSession(session);
+		}
+
+		return plaintextMessage;
+	}
+
+	@Override
+	public XmppAxolotlMessage.XmppAxolotlKeyTransportMessage processReceivingKeyTransportMessage(XmppAxolotlMessage message) {
+		XmppAxolotlMessage.XmppAxolotlKeyTransportMessage keyTransportMessage;
+
+		XmppAxolotlSession session = getReceivingSession(message);
+		keyTransportMessage = message.getParameters(session, getOwnDeviceId());
+
+		if (session.isFresh() && keyTransportMessage != null) {
+			putFreshSession(session);
+		}
+
+		return keyTransportMessage;
+	}
+
+	private void putFreshSession(XmppAxolotlSession session) {
+		Log.d(Config.LOGTAG,"put fresh session");
+		sessions.put(session);
+		if (Config.X509_VERIFICATION) {
+			if (session.getIdentityKey() != null) {
+				verifySessionWithPEP(session);
+			} else {
+				Log.e(Config.LOGTAG,account.getJid().toBareJid()+": identity key was empty after reloading for x509 verification");
+			}
+		}
+	}
+}
diff --git a/src/main/java/eu/siacs/conversations/crypto/axolotl/AxolotlServiceStub.java b/src/main/java/eu/siacs/conversations/crypto/axolotl/AxolotlServiceStub.java
new file mode 100644
index 00000000..42777b75
--- /dev/null
+++ b/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) {
+
+    }
+}
diff --git a/src/main/java/eu/siacs/conversations/crypto/axolotl/SQLiteAxolotlStore.java b/src/main/java/eu/siacs/conversations/crypto/axolotl/SQLiteAxolotlStore.java
index 3c8cb3c1..c634d877 100644
--- a/src/main/java/eu/siacs/conversations/crypto/axolotl/SQLiteAxolotlStore.java
+++ b/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!");
 		}
 	}
 
diff --git a/src/main/java/eu/siacs/conversations/crypto/axolotl/XmppAxolotlSession.java b/src/main/java/eu/siacs/conversations/crypto/axolotl/XmppAxolotlSession.java
index b713eb5f..93ed32a2 100644
--- a/src/main/java/eu/siacs/conversations/crypto/axolotl/XmppAxolotlSession.java
+++ b/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) {
diff --git a/src/main/java/eu/siacs/conversations/entities/Account.java b/src/main/java/eu/siacs/conversations/entities/Account.java
index 6791f417..7aee78b5 100644
--- a/src/main/java/eu/siacs/conversations/entities/Account.java
+++ b/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 (xmppConnection != null) {
-			xmppConnection.addOnAdvancedStreamFeaturesAvailableListener(axolotlService);
-		}
+        if (ConversationsPlusPreferences.omemoEnabled()) {
+            this.axolotlService = new AxolotlServiceImpl(this, context);
+            if (xmppConnection != null) {
+                xmppConnection.addOnAdvancedStreamFeaturesAvailableListener(axolotlService);
+            }
+        } else {
+            this.axolotlService = new AxolotlServiceStub();
+        }
+
 		this.pgpDecryptionService = new PgpDecryptionService(context);
 	}
 
diff --git a/src/main/java/eu/siacs/conversations/generator/AbstractGenerator.java b/src/main/java/eu/siacs/conversations/generator/AbstractGenerator.java
index 256c48de..649f767d 100644
--- a/src/main/java/eu/siacs/conversations/generator/AbstractGenerator.java
+++ b/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 = {
diff --git a/src/main/java/eu/siacs/conversations/generator/IqGenerator.java b/src/main/java/eu/siacs/conversations/generator/IqGenerator.java
index 0c1f6ee4..7216a78e 100644
--- a/src/main/java/eu/siacs/conversations/generator/IqGenerator.java
+++ b/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;
diff --git a/src/main/java/eu/siacs/conversations/parser/IqParser.java b/src/main/java/eu/siacs/conversations/parser/IqParser.java
index 99dfbab5..c03ed42f 100644
--- a/src/main/java/eu/siacs/conversations/parser/IqParser.java
+++ b/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) {
diff --git a/src/main/java/eu/siacs/conversations/parser/MessageParser.java b/src/main/java/eu/siacs/conversations/parser/MessageParser.java
index 480adf25..34f24f6f 100644
--- a/src/main/java/eu/siacs/conversations/parser/MessageParser.java
+++ b/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)) {
-			Log.d(Config.LOGTAG, AxolotlService.getLogprefix(account)+"Received PEP device list update from "+ from + ", processing...");
+		} else if (ConversationsPlusPreferences.omemoEnabled() && AxolotlService.PEP_DEVICE_LIST.equals(node)) {
+			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;
diff --git a/src/main/java/eu/siacs/conversations/persistance/DatabaseBackend.java b/src/main/java/eu/siacs/conversations/persistance/DatabaseBackend.java
index 96a04fa4..aa3f9eba 100644
--- a/src/main/java/eu/siacs/conversations/persistance/DatabaseBackend.java
+++ b/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
diff --git a/src/main/java/eu/siacs/conversations/ui/ConversationActivity.java b/src/main/java/eu/siacs/conversations/ui/ConversationActivity.java
index 0d021121..e11dafd3 100644
--- a/src/main/java/eu/siacs/conversations/ui/ConversationActivity.java
+++ b/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);
diff --git a/src/main/java/eu/siacs/conversations/ui/SettingsActivity.java b/src/main/java/eu/siacs/conversations/ui/SettingsActivity.java
index 852699e6..590d6259 100644
--- a/src/main/java/eu/siacs/conversations/ui/SettingsActivity.java
+++ b/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
diff --git a/src/main/res/layout/activity_edit_account.xml b/src/main/res/layout/activity_edit_account.xml
index cf49b3ac..58e168f3 100644
--- a/src/main/res/layout/activity_edit_account.xml
+++ b/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"
diff --git a/src/main/res/menu/encryption_choices.xml b/src/main/res/menu/encryption_choices.xml
index ab42a206..445c4114 100644
--- a/src/main/res/menu/encryption_choices.xml
+++ b/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"/>
diff --git a/src/main/res/values/encryption_settings.xml b/src/main/res/values/encryption_settings.xml
new file mode 100644
index 00000000..33db8387
--- /dev/null
+++ b/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>
\ No newline at end of file
diff --git a/src/main/res/values/strings.xml b/src/main/res/values/strings.xml
index 320bb6c2..f9850bc4 100644
--- a/src/main/res/values/strings.xml
+++ b/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>
diff --git a/src/main/res/xml/preferences.xml b/src/main/res/xml/preferences.xml
index 42e2fdd8..622e772c 100644
--- a/src/main/res/xml/preferences.xml
+++ b/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>