1package eu.siacs.conversations.crypto.axolotl;
   2
   3import android.os.Bundle;
   4import android.security.KeyChain;
   5import android.support.annotation.NonNull;
   6import android.support.annotation.Nullable;
   7import android.util.Log;
   8import android.util.Pair;
   9
  10import org.bouncycastle.jce.provider.BouncyCastleProvider;
  11import org.whispersystems.libaxolotl.AxolotlAddress;
  12import org.whispersystems.libaxolotl.IdentityKey;
  13import org.whispersystems.libaxolotl.IdentityKeyPair;
  14import org.whispersystems.libaxolotl.InvalidKeyException;
  15import org.whispersystems.libaxolotl.InvalidKeyIdException;
  16import org.whispersystems.libaxolotl.SessionBuilder;
  17import org.whispersystems.libaxolotl.UntrustedIdentityException;
  18import org.whispersystems.libaxolotl.ecc.ECPublicKey;
  19import org.whispersystems.libaxolotl.state.PreKeyBundle;
  20import org.whispersystems.libaxolotl.state.PreKeyRecord;
  21import org.whispersystems.libaxolotl.state.SignedPreKeyRecord;
  22import org.whispersystems.libaxolotl.util.KeyHelper;
  23
  24import java.security.PrivateKey;
  25import java.security.Security;
  26import java.security.Signature;
  27import java.security.cert.X509Certificate;
  28import java.util.ArrayList;
  29import java.util.Arrays;
  30import java.util.Collection;
  31import java.util.Collections;
  32import java.util.HashMap;
  33import java.util.HashSet;
  34import java.util.List;
  35import java.util.Map;
  36import java.util.Random;
  37import java.util.Set;
  38import java.util.concurrent.atomic.AtomicBoolean;
  39
  40import eu.siacs.conversations.Config;
  41import eu.siacs.conversations.entities.Account;
  42import eu.siacs.conversations.entities.Contact;
  43import eu.siacs.conversations.entities.Conversation;
  44import eu.siacs.conversations.entities.Message;
  45import eu.siacs.conversations.parser.IqParser;
  46import eu.siacs.conversations.services.XmppConnectionService;
  47import eu.siacs.conversations.utils.CryptoHelper;
  48import eu.siacs.conversations.utils.SerialSingleThreadExecutor;
  49import eu.siacs.conversations.xml.Element;
  50import eu.siacs.conversations.xmpp.OnAdvancedStreamFeaturesLoaded;
  51import eu.siacs.conversations.xmpp.OnIqPacketReceived;
  52import eu.siacs.conversations.xmpp.jid.InvalidJidException;
  53import eu.siacs.conversations.xmpp.jid.Jid;
  54import eu.siacs.conversations.xmpp.stanzas.IqPacket;
  55
  56public class AxolotlService implements OnAdvancedStreamFeaturesLoaded {
  57
  58	public static final String PEP_PREFIX = "eu.siacs.conversations.axolotl";
  59	public static final String PEP_DEVICE_LIST = PEP_PREFIX + ".devicelist";
  60	public static final String PEP_DEVICE_LIST_NOTIFY = PEP_DEVICE_LIST + "+notify";
  61	public static final String PEP_BUNDLES = PEP_PREFIX + ".bundles";
  62	public static final String PEP_VERIFICATION = PEP_PREFIX + ".verification";
  63
  64	public static final String LOGPREFIX = "AxolotlService";
  65
  66	public static final int NUM_KEYS_TO_PUBLISH = 100;
  67	public static final int publishTriesThreshold = 3;
  68
  69	private final Account account;
  70	private final XmppConnectionService mXmppConnectionService;
  71	private final SQLiteAxolotlStore axolotlStore;
  72	private final SessionMap sessions;
  73	private final Map<Jid, Set<Integer>> deviceIds;
  74	private final Map<String, XmppAxolotlMessage> messageCache;
  75	private final FetchStatusMap fetchStatusMap;
  76	private final SerialSingleThreadExecutor executor;
  77	private int numPublishTriesOnEmptyPep = 0;
  78	private boolean pepBroken = false;
  79
  80	private AtomicBoolean ownPushPending = new AtomicBoolean(false);
  81
  82	@Override
  83	public void onAdvancedStreamFeaturesAvailable(Account account) {
  84		if (Config.supportOmemo()
  85				&& account.getXmppConnection() != null
  86				&& account.getXmppConnection().getFeatures().pep()) {
  87			publishBundlesIfNeeded(true, false);
  88		} else {
  89			Log.d(Config.LOGTAG,account.getJid().toBareJid()+": skipping OMEMO initialization");
  90		}
  91	}
  92
  93	public boolean fetchMapHasErrors(List<Jid> jids) {
  94		for(Jid jid : jids) {
  95			if (deviceIds.get(jid) != null) {
  96				for (Integer foreignId : this.deviceIds.get(jid)) {
  97					AxolotlAddress address = new AxolotlAddress(jid.toString(), foreignId);
  98					if (fetchStatusMap.getAll(address).containsValue(FetchStatus.ERROR)) {
  99						return true;
 100					}
 101				}
 102			}
 103		}
 104		return false;
 105	}
 106
 107	public void preVerifyFingerprint(Contact contact, String fingerprint) {
 108		axolotlStore.preVerifyFingerprint(contact.getAccount(), contact.getJid().toBareJid().toPreppedString(), fingerprint);
 109	}
 110
 111	public void preVerifyFingerprint(Account account, String fingerprint) {
 112		axolotlStore.preVerifyFingerprint(account, account.getJid().toBareJid().toPreppedString(), fingerprint);
 113	}
 114
 115	public boolean hasVerifiedKeys(String name) {
 116		for(XmppAxolotlSession session : this.sessions.getAll(new AxolotlAddress(name,0)).values()) {
 117			if (session.getTrust().isVerified()) {
 118				return true;
 119			}
 120		}
 121		return false;
 122	}
 123
 124	private static class AxolotlAddressMap<T> {
 125		protected Map<String, Map<Integer, T>> map;
 126		protected final Object MAP_LOCK = new Object();
 127
 128		public AxolotlAddressMap() {
 129			this.map = new HashMap<>();
 130		}
 131
 132		public void put(AxolotlAddress address, T value) {
 133			synchronized (MAP_LOCK) {
 134				Map<Integer, T> devices = map.get(address.getName());
 135				if (devices == null) {
 136					devices = new HashMap<>();
 137					map.put(address.getName(), devices);
 138				}
 139				devices.put(address.getDeviceId(), value);
 140			}
 141		}
 142
 143		public T get(AxolotlAddress address) {
 144			synchronized (MAP_LOCK) {
 145				Map<Integer, T> devices = map.get(address.getName());
 146				if (devices == null) {
 147					return null;
 148				}
 149				return devices.get(address.getDeviceId());
 150			}
 151		}
 152
 153		public Map<Integer, T> getAll(AxolotlAddress address) {
 154			synchronized (MAP_LOCK) {
 155				Map<Integer, T> devices = map.get(address.getName());
 156				if (devices == null) {
 157					return new HashMap<>();
 158				}
 159				return devices;
 160			}
 161		}
 162
 163		public boolean hasAny(AxolotlAddress address) {
 164			synchronized (MAP_LOCK) {
 165				Map<Integer, T> devices = map.get(address.getName());
 166				return devices != null && !devices.isEmpty();
 167			}
 168		}
 169
 170		public void clear() {
 171			map.clear();
 172		}
 173
 174	}
 175
 176	private static class SessionMap extends AxolotlAddressMap<XmppAxolotlSession> {
 177		private final XmppConnectionService xmppConnectionService;
 178		private final Account account;
 179
 180		public SessionMap(XmppConnectionService service, SQLiteAxolotlStore store, Account account) {
 181			super();
 182			this.xmppConnectionService = service;
 183			this.account = account;
 184			this.fillMap(store);
 185		}
 186
 187		private void putDevicesForJid(String bareJid, List<Integer> deviceIds, SQLiteAxolotlStore store) {
 188			for (Integer deviceId : deviceIds) {
 189				AxolotlAddress axolotlAddress = new AxolotlAddress(bareJid, deviceId);
 190				IdentityKey identityKey = store.loadSession(axolotlAddress).getSessionState().getRemoteIdentityKey();
 191				if(Config.X509_VERIFICATION) {
 192					X509Certificate certificate = store.getFingerprintCertificate(identityKey.getFingerprint().replaceAll("\\s", ""));
 193					if (certificate != null) {
 194						Bundle information = CryptoHelper.extractCertificateInformation(certificate);
 195						try {
 196							final String cn = information.getString("subject_cn");
 197							final Jid jid = Jid.fromString(bareJid);
 198							Log.d(Config.LOGTAG,"setting common name for "+jid+" to "+cn);
 199							account.getRoster().getContact(jid).setCommonName(cn);
 200						} catch (final InvalidJidException ignored) {
 201							//ignored
 202						}
 203					}
 204				}
 205				this.put(axolotlAddress, new XmppAxolotlSession(account, store, axolotlAddress, identityKey));
 206			}
 207		}
 208
 209		private void fillMap(SQLiteAxolotlStore store) {
 210			List<Integer> deviceIds = store.getSubDeviceSessions(account.getJid().toBareJid().toPreppedString());
 211			putDevicesForJid(account.getJid().toBareJid().toPreppedString(), deviceIds, store);
 212			for (Contact contact : account.getRoster().getContacts()) {
 213				Jid bareJid = contact.getJid().toBareJid();
 214				String address = bareJid.toString();
 215				deviceIds = store.getSubDeviceSessions(address);
 216				putDevicesForJid(address, deviceIds, store);
 217			}
 218
 219		}
 220
 221		@Override
 222		public void put(AxolotlAddress address, XmppAxolotlSession value) {
 223			super.put(address, value);
 224			value.setNotFresh();
 225			xmppConnectionService.syncRosterToDisk(account); //TODO why?
 226		}
 227
 228		public void put(XmppAxolotlSession session) {
 229			this.put(session.getRemoteAddress(), session);
 230		}
 231	}
 232
 233	public enum FetchStatus {
 234		PENDING,
 235		SUCCESS,
 236		SUCCESS_VERIFIED,
 237		TIMEOUT,
 238		SUCCESS_TRUSTED,
 239		ERROR
 240	}
 241
 242	private static class FetchStatusMap extends AxolotlAddressMap<FetchStatus> {
 243
 244		public void clearErrorFor(Jid jid) {
 245			synchronized (MAP_LOCK) {
 246				Map<Integer, FetchStatus> devices = this.map.get(jid.toBareJid().toPreppedString());
 247				if (devices == null) {
 248					return;
 249				}
 250				for(Map.Entry<Integer, FetchStatus> entry : devices.entrySet()) {
 251					if (entry.getValue() == FetchStatus.ERROR) {
 252						Log.d(Config.LOGTAG,"resetting error for "+jid.toBareJid()+"("+entry.getKey()+")");
 253						entry.setValue(FetchStatus.TIMEOUT);
 254					}
 255				}
 256			}
 257		}
 258	}
 259
 260	public static String getLogprefix(Account account) {
 261		return LOGPREFIX + " (" + account.getJid().toBareJid().toString() + "): ";
 262	}
 263
 264	public AxolotlService(Account account, XmppConnectionService connectionService) {
 265		if (Security.getProvider("BC") == null) {
 266			Security.addProvider(new BouncyCastleProvider());
 267		}
 268		this.mXmppConnectionService = connectionService;
 269		this.account = account;
 270		this.axolotlStore = new SQLiteAxolotlStore(this.account, this.mXmppConnectionService);
 271		this.deviceIds = new HashMap<>();
 272		this.messageCache = new HashMap<>();
 273		this.sessions = new SessionMap(mXmppConnectionService, axolotlStore, account);
 274		this.fetchStatusMap = new FetchStatusMap();
 275		this.executor = new SerialSingleThreadExecutor();
 276	}
 277
 278	public String getOwnFingerprint() {
 279		return axolotlStore.getIdentityKeyPair().getPublicKey().getFingerprint().replaceAll("\\s", "");
 280	}
 281
 282	public Set<IdentityKey> getKeysWithTrust(FingerprintStatus status) {
 283		return axolotlStore.getContactKeysWithTrust(account.getJid().toBareJid().toPreppedString(), status);
 284	}
 285
 286	public Set<IdentityKey> getKeysWithTrust(FingerprintStatus status, Jid jid) {
 287		return axolotlStore.getContactKeysWithTrust(jid.toBareJid().toPreppedString(), status);
 288	}
 289
 290	public Set<IdentityKey> getKeysWithTrust(FingerprintStatus status, List<Jid> jids) {
 291		Set<IdentityKey> keys = new HashSet<>();
 292		for(Jid jid : jids) {
 293			keys.addAll(axolotlStore.getContactKeysWithTrust(jid.toPreppedString(), status));
 294		}
 295		return keys;
 296	}
 297
 298	public long getNumTrustedKeys(Jid jid) {
 299		return axolotlStore.getContactNumTrustedKeys(jid.toBareJid().toPreppedString());
 300	}
 301
 302	public boolean anyTargetHasNoTrustedKeys(List<Jid> jids) {
 303		for(Jid jid : jids) {
 304			if (axolotlStore.getContactNumTrustedKeys(jid.toBareJid().toPreppedString()) == 0) {
 305				return true;
 306			}
 307		}
 308		return false;
 309	}
 310
 311	private AxolotlAddress getAddressForJid(Jid jid) {
 312		return new AxolotlAddress(jid.toPreppedString(), 0);
 313	}
 314
 315	public Collection<XmppAxolotlSession> findOwnSessions() {
 316		AxolotlAddress ownAddress = getAddressForJid(account.getJid().toBareJid());
 317		ArrayList<XmppAxolotlSession> s = new ArrayList<>(this.sessions.getAll(ownAddress).values());
 318		Collections.sort(s);
 319		return s;
 320	}
 321
 322
 323
 324	public Collection<XmppAxolotlSession> findSessionsForContact(Contact contact) {
 325		AxolotlAddress contactAddress = getAddressForJid(contact.getJid());
 326		ArrayList<XmppAxolotlSession> s = new ArrayList<>(this.sessions.getAll(contactAddress).values());
 327		Collections.sort(s);
 328		return s;
 329	}
 330
 331	private Set<XmppAxolotlSession> findSessionsForConversation(Conversation conversation) {
 332		HashSet<XmppAxolotlSession> sessions = new HashSet<>();
 333		for(Jid jid : conversation.getAcceptedCryptoTargets()) {
 334			sessions.addAll(this.sessions.getAll(getAddressForJid(jid)).values());
 335		}
 336		return sessions;
 337	}
 338
 339	private boolean hasAny(Jid jid) {
 340		return sessions.hasAny(getAddressForJid(jid));
 341	}
 342
 343	public boolean isPepBroken() {
 344		return this.pepBroken;
 345	}
 346
 347	public void resetBrokenness() {
 348		this.pepBroken = false;
 349		numPublishTriesOnEmptyPep = 0;
 350	}
 351
 352	public void clearErrorsInFetchStatusMap(Jid jid) {
 353		fetchStatusMap.clearErrorFor(jid);
 354	}
 355
 356	public void regenerateKeys(boolean wipeOther) {
 357		axolotlStore.regenerate();
 358		sessions.clear();
 359		fetchStatusMap.clear();
 360		publishBundlesIfNeeded(true, wipeOther);
 361	}
 362
 363	public int getOwnDeviceId() {
 364		return axolotlStore.getLocalRegistrationId();
 365	}
 366
 367	public Set<Integer> getOwnDeviceIds() {
 368		return this.deviceIds.get(account.getJid().toBareJid());
 369	}
 370
 371	public void registerDevices(final Jid jid, @NonNull final Set<Integer> deviceIds) {
 372		boolean me = jid.toBareJid().equals(account.getJid().toBareJid());
 373		if (me && ownPushPending.getAndSet(false)) {
 374			Log.d(Config.LOGTAG,account.getJid().toBareJid()+": ignoring own device update because of pending push");
 375			return;
 376		}
 377		boolean needsPublishing = me && !deviceIds.contains(getOwnDeviceId());
 378		if (me) {
 379			deviceIds.remove(getOwnDeviceId());
 380		}
 381		Set<Integer> expiredDevices = new HashSet<>(axolotlStore.getSubDeviceSessions(jid.toBareJid().toPreppedString()));
 382		expiredDevices.removeAll(deviceIds);
 383		for (Integer deviceId : expiredDevices) {
 384			AxolotlAddress address = new AxolotlAddress(jid.toBareJid().toPreppedString(), deviceId);
 385			XmppAxolotlSession session = sessions.get(address);
 386			if (session != null && session.getFingerprint() != null) {
 387				if (session.getTrust().isActive()) {
 388					session.setTrust(session.getTrust().toInactive());
 389				}
 390			}
 391		}
 392		Set<Integer> newDevices = new HashSet<>(deviceIds);
 393		for (Integer deviceId : newDevices) {
 394			AxolotlAddress address = new AxolotlAddress(jid.toBareJid().toPreppedString(), deviceId);
 395			XmppAxolotlSession session = sessions.get(address);
 396			if (session != null && session.getFingerprint() != null) {
 397				if (!session.getTrust().isActive()) {
 398					Log.d(Config.LOGTAG,"reactivating device with fingprint "+session.getFingerprint());
 399					session.setTrust(session.getTrust().toActive());
 400				}
 401			}
 402		}
 403		if (me) {
 404			if (Config.OMEMO_AUTO_EXPIRY != 0) {
 405				needsPublishing |= deviceIds.removeAll(getExpiredDevices());
 406			}
 407			for (Integer deviceId : deviceIds) {
 408				AxolotlAddress ownDeviceAddress = new AxolotlAddress(jid.toBareJid().toPreppedString(), deviceId);
 409				if (sessions.get(ownDeviceAddress) == null) {
 410					buildSessionFromPEP(ownDeviceAddress);
 411				}
 412			}
 413			if (needsPublishing) {
 414				publishOwnDeviceId(deviceIds);
 415			}
 416		}
 417		this.deviceIds.put(jid, deviceIds);
 418		mXmppConnectionService.keyStatusUpdated(null);
 419	}
 420
 421	public void wipeOtherPepDevices() {
 422		if (pepBroken) {
 423			Log.d(Config.LOGTAG, getLogprefix(account) + "wipeOtherPepDevices called, but PEP is broken. Ignoring... ");
 424			return;
 425		}
 426		Set<Integer> deviceIds = new HashSet<>();
 427		deviceIds.add(getOwnDeviceId());
 428		IqPacket publish = mXmppConnectionService.getIqGenerator().publishDeviceIds(deviceIds);
 429		Log.d(Config.LOGTAG, AxolotlService.getLogprefix(account) + "Wiping all other devices from Pep:" + publish);
 430		mXmppConnectionService.sendIqPacket(account, publish, null);
 431	}
 432
 433	public void purgeKey(final String fingerprint) {
 434		axolotlStore.setFingerprintStatus(fingerprint.replaceAll("\\s", ""), FingerprintStatus.createCompromised());
 435	}
 436
 437	public void publishOwnDeviceIdIfNeeded() {
 438		if (pepBroken) {
 439			Log.d(Config.LOGTAG, getLogprefix(account) + "publishOwnDeviceIdIfNeeded called, but PEP is broken. Ignoring... ");
 440			return;
 441		}
 442		IqPacket packet = mXmppConnectionService.getIqGenerator().retrieveDeviceIds(account.getJid().toBareJid());
 443		mXmppConnectionService.sendIqPacket(account, packet, new OnIqPacketReceived() {
 444			@Override
 445			public void onIqPacketReceived(Account account, IqPacket packet) {
 446				if (packet.getType() == IqPacket.TYPE.TIMEOUT) {
 447					Log.d(Config.LOGTAG, getLogprefix(account) + "Timeout received while retrieving own Device Ids.");
 448				} else {
 449					Element item = mXmppConnectionService.getIqParser().getItem(packet);
 450					Set<Integer> deviceIds = mXmppConnectionService.getIqParser().deviceIds(item);
 451					registerDevices(account.getJid().toBareJid(),deviceIds);
 452				}
 453			}
 454		});
 455	}
 456
 457	private Set<Integer> getExpiredDevices() {
 458		Set<Integer> devices = new HashSet<>();
 459		for(XmppAxolotlSession session : findOwnSessions()) {
 460			if (session.getTrust().isActive()) {
 461				long diff = System.currentTimeMillis() - session.getTrust().getLastActivation();
 462				if (diff > Config.OMEMO_AUTO_EXPIRY) {
 463					long lastMessageDiff = System.currentTimeMillis() - mXmppConnectionService.databaseBackend.getLastTimeFingerprintUsed(account,session.getFingerprint());
 464					if (lastMessageDiff > Config.OMEMO_AUTO_EXPIRY) {
 465						devices.add(session.getRemoteAddress().getDeviceId());
 466						session.setTrust(session.getTrust().toInactive());
 467						Log.d(Config.LOGTAG, "added own device " + session.getFingerprint() + " to list of expired devices. Last message received "+(lastMessageDiff/1000)+"s ago");
 468					}
 469				}
 470			}
 471		}
 472		return devices;
 473	}
 474
 475	public void publishOwnDeviceId(Set<Integer> deviceIds) {
 476		Set<Integer> deviceIdsCopy = new HashSet<>(deviceIds);
 477		if (!deviceIdsCopy.contains(getOwnDeviceId())) {
 478			Log.d(Config.LOGTAG, AxolotlService.getLogprefix(account) + "Own device " + getOwnDeviceId() + " not in PEP devicelist.");
 479			if (deviceIdsCopy.isEmpty()) {
 480				if (numPublishTriesOnEmptyPep >= publishTriesThreshold) {
 481					Log.w(Config.LOGTAG, getLogprefix(account) + "Own device publish attempt threshold exceeded, aborting...");
 482					pepBroken = true;
 483					return;
 484				} else {
 485					numPublishTriesOnEmptyPep++;
 486					Log.w(Config.LOGTAG, getLogprefix(account) + "Own device list empty, attempting to publish (try " + numPublishTriesOnEmptyPep + ")");
 487				}
 488			} else {
 489				numPublishTriesOnEmptyPep = 0;
 490			}
 491			deviceIdsCopy.add(getOwnDeviceId());
 492			IqPacket publish = mXmppConnectionService.getIqGenerator().publishDeviceIds(deviceIdsCopy);
 493			ownPushPending.set(true);
 494			mXmppConnectionService.sendIqPacket(account, publish, new OnIqPacketReceived() {
 495				@Override
 496				public void onIqPacketReceived(Account account, IqPacket packet) {
 497					ownPushPending.set(false);
 498					if (packet.getType() == IqPacket.TYPE.ERROR) {
 499						pepBroken = true;
 500						Log.d(Config.LOGTAG, getLogprefix(account) + "Error received while publishing own device id" + packet.findChild("error"));
 501					}
 502				}
 503			});
 504		}
 505	}
 506
 507	public void publishDeviceVerificationAndBundle(final SignedPreKeyRecord signedPreKeyRecord,
 508												   final Set<PreKeyRecord> preKeyRecords,
 509												   final boolean announceAfter,
 510												   final boolean wipe) {
 511		try {
 512			IdentityKey axolotlPublicKey = axolotlStore.getIdentityKeyPair().getPublicKey();
 513			PrivateKey x509PrivateKey = KeyChain.getPrivateKey(mXmppConnectionService, account.getPrivateKeyAlias());
 514			X509Certificate[] chain = KeyChain.getCertificateChain(mXmppConnectionService, account.getPrivateKeyAlias());
 515			Signature verifier = Signature.getInstance("sha256WithRSA");
 516			verifier.initSign(x509PrivateKey,mXmppConnectionService.getRNG());
 517			verifier.update(axolotlPublicKey.serialize());
 518			byte[] signature = verifier.sign();
 519			IqPacket packet = mXmppConnectionService.getIqGenerator().publishVerification(signature, chain, getOwnDeviceId());
 520			Log.d(Config.LOGTAG, AxolotlService.getLogprefix(account) + ": publish verification for device "+getOwnDeviceId());
 521			mXmppConnectionService.sendIqPacket(account, packet, new OnIqPacketReceived() {
 522				@Override
 523				public void onIqPacketReceived(Account account, IqPacket packet) {
 524					publishDeviceBundle(signedPreKeyRecord, preKeyRecords, announceAfter, wipe);
 525				}
 526			});
 527		} catch (Exception  e) {
 528			e.printStackTrace();
 529		}
 530	}
 531
 532	public void publishBundlesIfNeeded(final boolean announce, final boolean wipe) {
 533		if (pepBroken) {
 534			Log.d(Config.LOGTAG, getLogprefix(account) + "publishBundlesIfNeeded called, but PEP is broken. Ignoring... ");
 535			return;
 536		}
 537		IqPacket packet = mXmppConnectionService.getIqGenerator().retrieveBundlesForDevice(account.getJid().toBareJid(), getOwnDeviceId());
 538		mXmppConnectionService.sendIqPacket(account, packet, new OnIqPacketReceived() {
 539			@Override
 540			public void onIqPacketReceived(Account account, IqPacket packet) {
 541
 542				if (packet.getType() == IqPacket.TYPE.TIMEOUT) {
 543					return; //ignore timeout. do nothing
 544				}
 545
 546				if (packet.getType() == IqPacket.TYPE.ERROR) {
 547					Element error = packet.findChild("error");
 548					if (error == null || !error.hasChild("item-not-found")) {
 549						pepBroken = true;
 550						Log.w(Config.LOGTAG, AxolotlService.getLogprefix(account) + "request for device bundles came back with something other than item-not-found" + packet);
 551						return;
 552					}
 553				}
 554
 555				PreKeyBundle bundle = mXmppConnectionService.getIqParser().bundle(packet);
 556				Map<Integer, ECPublicKey> keys = mXmppConnectionService.getIqParser().preKeyPublics(packet);
 557				boolean flush = false;
 558				if (bundle == null) {
 559					Log.w(Config.LOGTAG, AxolotlService.getLogprefix(account) + "Received invalid bundle:" + packet);
 560					bundle = new PreKeyBundle(-1, -1, -1, null, -1, null, null, null);
 561					flush = true;
 562				}
 563				if (keys == null) {
 564					Log.w(Config.LOGTAG, AxolotlService.getLogprefix(account) + "Received invalid prekeys:" + packet);
 565				}
 566				try {
 567					boolean changed = false;
 568					// Validate IdentityKey
 569					IdentityKeyPair identityKeyPair = axolotlStore.getIdentityKeyPair();
 570					if (flush || !identityKeyPair.getPublicKey().equals(bundle.getIdentityKey())) {
 571						Log.i(Config.LOGTAG, AxolotlService.getLogprefix(account) + "Adding own IdentityKey " + identityKeyPair.getPublicKey() + " to PEP.");
 572						changed = true;
 573					}
 574
 575					// Validate signedPreKeyRecord + ID
 576					SignedPreKeyRecord signedPreKeyRecord;
 577					int numSignedPreKeys = axolotlStore.loadSignedPreKeys().size();
 578					try {
 579						signedPreKeyRecord = axolotlStore.loadSignedPreKey(bundle.getSignedPreKeyId());
 580						if (flush
 581								|| !bundle.getSignedPreKey().equals(signedPreKeyRecord.getKeyPair().getPublicKey())
 582								|| !Arrays.equals(bundle.getSignedPreKeySignature(), signedPreKeyRecord.getSignature())) {
 583							Log.i(Config.LOGTAG, AxolotlService.getLogprefix(account) + "Adding new signedPreKey with ID " + (numSignedPreKeys + 1) + " to PEP.");
 584							signedPreKeyRecord = KeyHelper.generateSignedPreKey(identityKeyPair, numSignedPreKeys + 1);
 585							axolotlStore.storeSignedPreKey(signedPreKeyRecord.getId(), signedPreKeyRecord);
 586							changed = true;
 587						}
 588					} catch (InvalidKeyIdException e) {
 589						Log.i(Config.LOGTAG, AxolotlService.getLogprefix(account) + "Adding new signedPreKey with ID " + (numSignedPreKeys + 1) + " to PEP.");
 590						signedPreKeyRecord = KeyHelper.generateSignedPreKey(identityKeyPair, numSignedPreKeys + 1);
 591						axolotlStore.storeSignedPreKey(signedPreKeyRecord.getId(), signedPreKeyRecord);
 592						changed = true;
 593					}
 594
 595					// Validate PreKeys
 596					Set<PreKeyRecord> preKeyRecords = new HashSet<>();
 597					if (keys != null) {
 598						for (Integer id : keys.keySet()) {
 599							try {
 600								PreKeyRecord preKeyRecord = axolotlStore.loadPreKey(id);
 601								if (preKeyRecord.getKeyPair().getPublicKey().equals(keys.get(id))) {
 602									preKeyRecords.add(preKeyRecord);
 603								}
 604							} catch (InvalidKeyIdException ignored) {
 605							}
 606						}
 607					}
 608					int newKeys = NUM_KEYS_TO_PUBLISH - preKeyRecords.size();
 609					if (newKeys > 0) {
 610						List<PreKeyRecord> newRecords = KeyHelper.generatePreKeys(
 611								axolotlStore.getCurrentPreKeyId() + 1, newKeys);
 612						preKeyRecords.addAll(newRecords);
 613						for (PreKeyRecord record : newRecords) {
 614							axolotlStore.storePreKey(record.getId(), record);
 615						}
 616						changed = true;
 617						Log.i(Config.LOGTAG, AxolotlService.getLogprefix(account) + "Adding " + newKeys + " new preKeys to PEP.");
 618					}
 619
 620
 621					if (changed) {
 622						if (account.getPrivateKeyAlias() != null && Config.X509_VERIFICATION) {
 623							mXmppConnectionService.publishDisplayName(account);
 624							publishDeviceVerificationAndBundle(signedPreKeyRecord, preKeyRecords, announce, wipe);
 625						} else {
 626							publishDeviceBundle(signedPreKeyRecord, preKeyRecords, announce, wipe);
 627						}
 628					} else {
 629						Log.d(Config.LOGTAG, getLogprefix(account) + "Bundle " + getOwnDeviceId() + " in PEP was current");
 630						if (wipe) {
 631							wipeOtherPepDevices();
 632						} else if (announce) {
 633							Log.d(Config.LOGTAG, getLogprefix(account) + "Announcing device " + getOwnDeviceId());
 634							publishOwnDeviceIdIfNeeded();
 635						}
 636					}
 637				} catch (InvalidKeyException e) {
 638					Log.e(Config.LOGTAG, AxolotlService.getLogprefix(account) + "Failed to publish bundle " + getOwnDeviceId() + ", reason: " + e.getMessage());
 639				}
 640			}
 641		});
 642	}
 643
 644	private void publishDeviceBundle(SignedPreKeyRecord signedPreKeyRecord,
 645									 Set<PreKeyRecord> preKeyRecords,
 646									 final boolean announceAfter,
 647									 final boolean wipe) {
 648		IqPacket publish = mXmppConnectionService.getIqGenerator().publishBundles(
 649				signedPreKeyRecord, axolotlStore.getIdentityKeyPair().getPublicKey(),
 650				preKeyRecords, getOwnDeviceId());
 651		Log.d(Config.LOGTAG, AxolotlService.getLogprefix(account) + ": Bundle " + getOwnDeviceId() + " in PEP not current. Publishing: " + publish);
 652		mXmppConnectionService.sendIqPacket(account, publish, new OnIqPacketReceived() {
 653			@Override
 654			public void onIqPacketReceived(Account account, IqPacket packet) {
 655				if (packet.getType() == IqPacket.TYPE.RESULT) {
 656					Log.d(Config.LOGTAG, AxolotlService.getLogprefix(account) + "Successfully published bundle. ");
 657					if (wipe) {
 658						wipeOtherPepDevices();
 659					} else if (announceAfter) {
 660						Log.d(Config.LOGTAG, getLogprefix(account) + "Announcing device " + getOwnDeviceId());
 661						publishOwnDeviceIdIfNeeded();
 662					}
 663				} else if (packet.getType() == IqPacket.TYPE.ERROR) {
 664					pepBroken = true;
 665					Log.d(Config.LOGTAG, getLogprefix(account) + "Error received while publishing bundle: " + packet.findChild("error"));
 666				}
 667			}
 668		});
 669	}
 670
 671	public enum AxolotlCapability {
 672		FULL,
 673		MISSING_PRESENCE,
 674		MISSING_KEYS,
 675		WRONG_CONFIGURATION,
 676		NO_MEMBERS
 677	}
 678
 679	public boolean isConversationAxolotlCapable(Conversation conversation) {
 680		return isConversationAxolotlCapableDetailed(conversation).first == AxolotlCapability.FULL;
 681	}
 682
 683	public Pair<AxolotlCapability,Jid> isConversationAxolotlCapableDetailed(Conversation conversation) {
 684		if (conversation.getMode() == Conversation.MODE_SINGLE
 685				|| (conversation.getMucOptions().membersOnly() && conversation.getMucOptions().nonanonymous())) {
 686			final List<Jid> jids = getCryptoTargets(conversation);
 687			for(Jid jid : jids) {
 688				if (!hasAny(jid) && (!deviceIds.containsKey(jid) || deviceIds.get(jid).isEmpty())) {
 689					if (conversation.getAccount().getRoster().getContact(jid).mutualPresenceSubscription()) {
 690						return new Pair<>(AxolotlCapability.MISSING_KEYS,jid);
 691					} else {
 692						return new Pair<>(AxolotlCapability.MISSING_PRESENCE,jid);
 693					}
 694				}
 695			}
 696			if (jids.size() > 0) {
 697				return new Pair<>(AxolotlCapability.FULL, null);
 698			} else {
 699				return new Pair<>(AxolotlCapability.NO_MEMBERS, null);
 700			}
 701		} else {
 702			return new Pair<>(AxolotlCapability.WRONG_CONFIGURATION, null);
 703		}
 704	}
 705
 706	public List<Jid> getCryptoTargets(Conversation conversation) {
 707		final List<Jid> jids;
 708		if (conversation.getMode() == Conversation.MODE_SINGLE) {
 709			jids = Arrays.asList(conversation.getJid().toBareJid());
 710		} else {
 711			jids = conversation.getMucOptions().getMembers();
 712		}
 713		return jids;
 714	}
 715
 716	public FingerprintStatus getFingerprintTrust(String fingerprint) {
 717		return axolotlStore.getFingerprintStatus(fingerprint);
 718	}
 719
 720	public X509Certificate getFingerprintCertificate(String fingerprint) {
 721		return axolotlStore.getFingerprintCertificate(fingerprint);
 722	}
 723
 724	public void setFingerprintTrust(String fingerprint, FingerprintStatus status) {
 725		axolotlStore.setFingerprintStatus(fingerprint, status);
 726	}
 727
 728	private void verifySessionWithPEP(final XmppAxolotlSession session) {
 729		Log.d(Config.LOGTAG, "trying to verify fresh session (" + session.getRemoteAddress().getName() + ") with pep");
 730		final AxolotlAddress address = session.getRemoteAddress();
 731		final IdentityKey identityKey = session.getIdentityKey();
 732		try {
 733			IqPacket packet = mXmppConnectionService.getIqGenerator().retrieveVerificationForDevice(Jid.fromString(address.getName()), address.getDeviceId());
 734			mXmppConnectionService.sendIqPacket(account, packet, new OnIqPacketReceived() {
 735				@Override
 736				public void onIqPacketReceived(Account account, IqPacket packet) {
 737					Pair<X509Certificate[],byte[]> verification = mXmppConnectionService.getIqParser().verification(packet);
 738					if (verification != null) {
 739						try {
 740							Signature verifier = Signature.getInstance("sha256WithRSA");
 741							verifier.initVerify(verification.first[0]);
 742							verifier.update(identityKey.serialize());
 743							if (verifier.verify(verification.second)) {
 744								try {
 745									mXmppConnectionService.getMemorizingTrustManager().getNonInteractive().checkClientTrusted(verification.first, "RSA");
 746									String fingerprint = session.getFingerprint();
 747									Log.d(Config.LOGTAG, "verified session with x.509 signature. fingerprint was: "+fingerprint);
 748									setFingerprintTrust(fingerprint, FingerprintStatus.createActiveVerified(true));
 749									axolotlStore.setFingerprintCertificate(fingerprint, verification.first[0]);
 750									fetchStatusMap.put(address, FetchStatus.SUCCESS_VERIFIED);
 751									Bundle information = CryptoHelper.extractCertificateInformation(verification.first[0]);
 752									try {
 753										final String cn = information.getString("subject_cn");
 754										final Jid jid = Jid.fromString(address.getName());
 755										Log.d(Config.LOGTAG,"setting common name for "+jid+" to "+cn);
 756										account.getRoster().getContact(jid).setCommonName(cn);
 757									} catch (final InvalidJidException ignored) {
 758										//ignored
 759									}
 760									finishBuildingSessionsFromPEP(address);
 761									return;
 762								} catch (Exception e) {
 763									Log.d(Config.LOGTAG,"could not verify certificate");
 764								}
 765							}
 766						} catch (Exception e) {
 767							Log.d(Config.LOGTAG, "error during verification " + e.getMessage());
 768						}
 769					} else {
 770						Log.d(Config.LOGTAG,"no verification found");
 771					}
 772					fetchStatusMap.put(address, FetchStatus.SUCCESS);
 773					finishBuildingSessionsFromPEP(address);
 774				}
 775			});
 776		} catch (InvalidJidException e) {
 777			fetchStatusMap.put(address, FetchStatus.SUCCESS);
 778			finishBuildingSessionsFromPEP(address);
 779		}
 780	}
 781
 782	private void finishBuildingSessionsFromPEP(final AxolotlAddress address) {
 783		AxolotlAddress ownAddress = new AxolotlAddress(account.getJid().toBareJid().toPreppedString(), 0);
 784		Map<Integer, FetchStatus> own = fetchStatusMap.getAll(ownAddress);
 785		Map<Integer, FetchStatus> remote = fetchStatusMap.getAll(address);
 786		if (!own.containsValue(FetchStatus.PENDING) && !remote.containsValue(FetchStatus.PENDING)) {
 787			FetchStatus report = null;
 788			if (own.containsValue(FetchStatus.SUCCESS) || remote.containsValue(FetchStatus.SUCCESS)) {
 789				report = FetchStatus.SUCCESS;
 790			} else if (own.containsValue(FetchStatus.SUCCESS_VERIFIED) || remote.containsValue(FetchStatus.SUCCESS_VERIFIED)) {
 791				report = FetchStatus.SUCCESS_VERIFIED;
 792			} else if (own.containsValue(FetchStatus.SUCCESS_TRUSTED) || remote.containsValue(FetchStatus.SUCCESS_TRUSTED)) {
 793				report = FetchStatus.SUCCESS_TRUSTED;
 794			} else if (own.containsValue(FetchStatus.ERROR) || remote.containsValue(FetchStatus.ERROR)) {
 795				report = FetchStatus.ERROR;
 796			}
 797			mXmppConnectionService.keyStatusUpdated(report);
 798		}
 799	}
 800
 801	private void buildSessionFromPEP(final AxolotlAddress address) {
 802		Log.i(Config.LOGTAG, AxolotlService.getLogprefix(account) + "Building new sesstion for " + address.toString());
 803		if (address.getDeviceId() == getOwnDeviceId()) {
 804			throw new AssertionError("We should NEVER build a session with ourselves. What happened here?!");
 805		}
 806
 807		try {
 808			IqPacket bundlesPacket = mXmppConnectionService.getIqGenerator().retrieveBundlesForDevice(
 809					Jid.fromString(address.getName()), address.getDeviceId());
 810			Log.d(Config.LOGTAG, AxolotlService.getLogprefix(account) + "Retrieving bundle: " + bundlesPacket);
 811			mXmppConnectionService.sendIqPacket(account, bundlesPacket, new OnIqPacketReceived() {
 812
 813				@Override
 814				public void onIqPacketReceived(Account account, IqPacket packet) {
 815					if (packet.getType() == IqPacket.TYPE.TIMEOUT) {
 816						fetchStatusMap.put(address, FetchStatus.TIMEOUT);
 817					} else if (packet.getType() == IqPacket.TYPE.RESULT) {
 818						Log.d(Config.LOGTAG, AxolotlService.getLogprefix(account) + "Received preKey IQ packet, processing...");
 819						final IqParser parser = mXmppConnectionService.getIqParser();
 820						final List<PreKeyBundle> preKeyBundleList = parser.preKeys(packet);
 821						final PreKeyBundle bundle = parser.bundle(packet);
 822						if (preKeyBundleList.isEmpty() || bundle == null) {
 823							Log.e(Config.LOGTAG, AxolotlService.getLogprefix(account) + "preKey IQ packet invalid: " + packet);
 824							fetchStatusMap.put(address, FetchStatus.ERROR);
 825							finishBuildingSessionsFromPEP(address);
 826							return;
 827						}
 828						Random random = new Random();
 829						final PreKeyBundle preKey = preKeyBundleList.get(random.nextInt(preKeyBundleList.size()));
 830						if (preKey == null) {
 831							//should never happen
 832							fetchStatusMap.put(address, FetchStatus.ERROR);
 833							finishBuildingSessionsFromPEP(address);
 834							return;
 835						}
 836
 837						final PreKeyBundle preKeyBundle = new PreKeyBundle(0, address.getDeviceId(),
 838								preKey.getPreKeyId(), preKey.getPreKey(),
 839								bundle.getSignedPreKeyId(), bundle.getSignedPreKey(),
 840								bundle.getSignedPreKeySignature(), bundle.getIdentityKey());
 841
 842						try {
 843							SessionBuilder builder = new SessionBuilder(axolotlStore, address);
 844							builder.process(preKeyBundle);
 845							XmppAxolotlSession session = new XmppAxolotlSession(account, axolotlStore, address, bundle.getIdentityKey());
 846							sessions.put(address, session);
 847							if (Config.X509_VERIFICATION) {
 848								verifySessionWithPEP(session);
 849							} else {
 850								FingerprintStatus status = getFingerprintTrust(bundle.getIdentityKey().getFingerprint().replaceAll("\\s",""));
 851								FetchStatus fetchStatus;
 852								if (status != null && status.isVerified()) {
 853									fetchStatus = FetchStatus.SUCCESS_VERIFIED;
 854								} else if (status != null && status.isTrusted()) {
 855									fetchStatus = FetchStatus.SUCCESS_TRUSTED;
 856								} else {
 857									fetchStatus = FetchStatus.SUCCESS;
 858								}
 859								fetchStatusMap.put(address, fetchStatus);
 860								finishBuildingSessionsFromPEP(address);
 861							}
 862						} catch (UntrustedIdentityException | InvalidKeyException e) {
 863							Log.e(Config.LOGTAG, AxolotlService.getLogprefix(account) + "Error building session for " + address + ": "
 864									+ e.getClass().getName() + ", " + e.getMessage());
 865							fetchStatusMap.put(address, FetchStatus.ERROR);
 866							finishBuildingSessionsFromPEP(address);
 867						}
 868					} else {
 869						fetchStatusMap.put(address, FetchStatus.ERROR);
 870						Log.d(Config.LOGTAG, getLogprefix(account) + "Error received while building session:" + packet.findChild("error"));
 871						finishBuildingSessionsFromPEP(address);
 872					}
 873				}
 874			});
 875		} catch (InvalidJidException e) {
 876			Log.e(Config.LOGTAG, AxolotlService.getLogprefix(account) + "Got address with invalid jid: " + address.getName());
 877		}
 878	}
 879
 880	public Set<AxolotlAddress> findDevicesWithoutSession(final Conversation conversation) {
 881		Set<AxolotlAddress> addresses = new HashSet<>();
 882		for(Jid jid : getCryptoTargets(conversation)) {
 883			Log.d(Config.LOGTAG, AxolotlService.getLogprefix(account) + "Finding devices without session for " + jid);
 884			if (deviceIds.get(jid) != null) {
 885				for (Integer foreignId : this.deviceIds.get(jid)) {
 886					AxolotlAddress address = new AxolotlAddress(jid.toString(), foreignId);
 887					if (sessions.get(address) == null) {
 888						IdentityKey identityKey = axolotlStore.loadSession(address).getSessionState().getRemoteIdentityKey();
 889						if (identityKey != null) {
 890							Log.d(Config.LOGTAG, AxolotlService.getLogprefix(account) + "Already have session for " + address.toString() + ", adding to cache...");
 891							XmppAxolotlSession session = new XmppAxolotlSession(account, axolotlStore, address, identityKey);
 892							sessions.put(address, session);
 893						} else {
 894							Log.d(Config.LOGTAG, AxolotlService.getLogprefix(account) + "Found device " + jid + ":" + foreignId);
 895							if (fetchStatusMap.get(address) != FetchStatus.ERROR) {
 896								addresses.add(address);
 897							} else {
 898								Log.d(Config.LOGTAG, getLogprefix(account) + "skipping over " + address + " because it's broken");
 899							}
 900						}
 901					}
 902				}
 903			} else {
 904				Log.w(Config.LOGTAG, AxolotlService.getLogprefix(account) + "Have no target devices in PEP!");
 905			}
 906		}
 907		if (deviceIds.get(account.getJid().toBareJid()) != null) {
 908			for (Integer ownId : this.deviceIds.get(account.getJid().toBareJid())) {
 909				AxolotlAddress address = new AxolotlAddress(account.getJid().toBareJid().toPreppedString(), ownId);
 910				if (sessions.get(address) == null) {
 911					IdentityKey identityKey = axolotlStore.loadSession(address).getSessionState().getRemoteIdentityKey();
 912					if (identityKey != null) {
 913						Log.d(Config.LOGTAG, AxolotlService.getLogprefix(account) + "Already have session for " + address.toString() + ", adding to cache...");
 914						XmppAxolotlSession session = new XmppAxolotlSession(account, axolotlStore, address, identityKey);
 915						sessions.put(address, session);
 916					} else {
 917						Log.d(Config.LOGTAG, AxolotlService.getLogprefix(account) + "Found device " + account.getJid().toBareJid() + ":" + ownId);
 918						if (fetchStatusMap.get(address) != FetchStatus.ERROR) {
 919							addresses.add(address);
 920						} else {
 921							Log.d(Config.LOGTAG,getLogprefix(account)+"skipping over "+address+" because it's broken");
 922						}
 923					}
 924				}
 925			}
 926		}
 927
 928		return addresses;
 929	}
 930
 931	public boolean createSessionsIfNeeded(final Conversation conversation) {
 932		Log.i(Config.LOGTAG, AxolotlService.getLogprefix(account) + "Creating axolotl sessions if needed...");
 933		boolean newSessions = false;
 934		Set<AxolotlAddress> addresses = findDevicesWithoutSession(conversation);
 935		for (AxolotlAddress address : addresses) {
 936			Log.d(Config.LOGTAG, AxolotlService.getLogprefix(account) + "Processing device: " + address.toString());
 937			FetchStatus status = fetchStatusMap.get(address);
 938			if (status == null || status == FetchStatus.TIMEOUT) {
 939				fetchStatusMap.put(address, FetchStatus.PENDING);
 940				this.buildSessionFromPEP(address);
 941				newSessions = true;
 942			} else if (status == FetchStatus.PENDING) {
 943				newSessions = true;
 944			} else {
 945				Log.d(Config.LOGTAG, AxolotlService.getLogprefix(account) + "Already fetching bundle for " + address.toString());
 946			}
 947		}
 948
 949		return newSessions;
 950	}
 951
 952	public boolean trustedSessionVerified(final Conversation conversation) {
 953		Set<XmppAxolotlSession> sessions = findSessionsForConversation(conversation);
 954		sessions.addAll(findOwnSessions());
 955		boolean verified = false;
 956		for(XmppAxolotlSession session : sessions) {
 957			if (session.getTrust().isTrustedAndActive()) {
 958				if (session.getTrust().getTrust() == FingerprintStatus.Trust.VERIFIED_X509) {
 959					verified = true;
 960				} else {
 961					return false;
 962				}
 963			}
 964		}
 965		return verified;
 966	}
 967
 968	public boolean hasPendingKeyFetches(Account account, List<Jid> jids) {
 969		AxolotlAddress ownAddress = new AxolotlAddress(account.getJid().toBareJid().toPreppedString(), 0);
 970		if (fetchStatusMap.getAll(ownAddress).containsValue(FetchStatus.PENDING)) {
 971			return true;
 972		}
 973		for(Jid jid : jids) {
 974			AxolotlAddress foreignAddress = new AxolotlAddress(jid.toBareJid().toPreppedString(), 0);
 975			if (fetchStatusMap.getAll(foreignAddress).containsValue(FetchStatus.PENDING)) {
 976				return true;
 977			}
 978		}
 979		return false;
 980	}
 981
 982	@Nullable
 983	private XmppAxolotlMessage buildHeader(Conversation conversation) {
 984		final XmppAxolotlMessage axolotlMessage = new XmppAxolotlMessage(
 985				account.getJid().toBareJid(), getOwnDeviceId());
 986
 987		Set<XmppAxolotlSession> remoteSessions = findSessionsForConversation(conversation);
 988		Collection<XmppAxolotlSession> ownSessions = findOwnSessions();
 989		if (remoteSessions.isEmpty()) {
 990			return null;
 991		}
 992		for (XmppAxolotlSession session : remoteSessions) {
 993			axolotlMessage.addDevice(session);
 994		}
 995		for (XmppAxolotlSession session : ownSessions) {
 996			axolotlMessage.addDevice(session);
 997		}
 998
 999		return axolotlMessage;
1000	}
1001
1002	@Nullable
1003	public XmppAxolotlMessage encrypt(Message message) {
1004		XmppAxolotlMessage axolotlMessage = buildHeader(message.getConversation());
1005
1006		if (axolotlMessage != null) {
1007			final String content;
1008			if (message.hasFileOnRemoteHost()) {
1009				content = message.getFileParams().url.toString();
1010			} else {
1011				content = message.getBody();
1012			}
1013			try {
1014				axolotlMessage.encrypt(content);
1015			} catch (CryptoFailedException e) {
1016				Log.w(Config.LOGTAG, getLogprefix(account) + "Failed to encrypt message: " + e.getMessage());
1017				return null;
1018			}
1019		}
1020
1021		return axolotlMessage;
1022	}
1023
1024	public void preparePayloadMessage(final Message message, final boolean delay) {
1025		executor.execute(new Runnable() {
1026			@Override
1027			public void run() {
1028				XmppAxolotlMessage axolotlMessage = encrypt(message);
1029				if (axolotlMessage == null) {
1030					mXmppConnectionService.markMessage(message, Message.STATUS_SEND_FAILED);
1031					//mXmppConnectionService.updateConversationUi();
1032				} else {
1033					Log.d(Config.LOGTAG, AxolotlService.getLogprefix(account) + "Generated message, caching: " + message.getUuid());
1034					messageCache.put(message.getUuid(), axolotlMessage);
1035					mXmppConnectionService.resendMessage(message, delay);
1036				}
1037			}
1038		});
1039	}
1040
1041	public void prepareKeyTransportMessage(final Conversation conversation, final OnMessageCreatedCallback onMessageCreatedCallback) {
1042		executor.execute(new Runnable() {
1043			@Override
1044			public void run() {
1045				XmppAxolotlMessage axolotlMessage = buildHeader(conversation);
1046				onMessageCreatedCallback.run(axolotlMessage);
1047			}
1048		});
1049	}
1050
1051	public XmppAxolotlMessage fetchAxolotlMessageFromCache(Message message) {
1052		XmppAxolotlMessage axolotlMessage = messageCache.get(message.getUuid());
1053		if (axolotlMessage != null) {
1054			Log.d(Config.LOGTAG, AxolotlService.getLogprefix(account) + "Cache hit: " + message.getUuid());
1055			messageCache.remove(message.getUuid());
1056		} else {
1057			Log.d(Config.LOGTAG, AxolotlService.getLogprefix(account) + "Cache miss: " + message.getUuid());
1058		}
1059		return axolotlMessage;
1060	}
1061
1062	private XmppAxolotlSession recreateUncachedSession(AxolotlAddress address) {
1063		IdentityKey identityKey = axolotlStore.loadSession(address).getSessionState().getRemoteIdentityKey();
1064		return (identityKey != null)
1065				? new XmppAxolotlSession(account, axolotlStore, address, identityKey)
1066				: null;
1067	}
1068
1069	private XmppAxolotlSession getReceivingSession(XmppAxolotlMessage message) {
1070		AxolotlAddress senderAddress = new AxolotlAddress(message.getFrom().toString(),
1071				message.getSenderDeviceId());
1072		XmppAxolotlSession session = sessions.get(senderAddress);
1073		if (session == null) {
1074			Log.d(Config.LOGTAG, AxolotlService.getLogprefix(account) + "Account: " + account.getJid() + " No axolotl session found while parsing received message " + message);
1075			session = recreateUncachedSession(senderAddress);
1076			if (session == null) {
1077				session = new XmppAxolotlSession(account, axolotlStore, senderAddress);
1078			}
1079		}
1080		return session;
1081	}
1082
1083	public XmppAxolotlMessage.XmppAxolotlPlaintextMessage processReceivingPayloadMessage(XmppAxolotlMessage message) {
1084		XmppAxolotlMessage.XmppAxolotlPlaintextMessage plaintextMessage = null;
1085
1086		XmppAxolotlSession session = getReceivingSession(message);
1087		try {
1088			plaintextMessage = message.decrypt(session, getOwnDeviceId());
1089			Integer preKeyId = session.getPreKeyId();
1090			if (preKeyId != null) {
1091				publishBundlesIfNeeded(false, false);
1092				session.resetPreKeyId();
1093			}
1094		} catch (CryptoFailedException e) {
1095			Log.w(Config.LOGTAG, getLogprefix(account) + "Failed to decrypt message: " + e.getMessage());
1096		}
1097
1098		if (session.isFresh() && plaintextMessage != null) {
1099			putFreshSession(session);
1100		}
1101
1102		return plaintextMessage;
1103	}
1104
1105	public XmppAxolotlMessage.XmppAxolotlKeyTransportMessage processReceivingKeyTransportMessage(XmppAxolotlMessage message) {
1106		XmppAxolotlMessage.XmppAxolotlKeyTransportMessage keyTransportMessage;
1107
1108		XmppAxolotlSession session = getReceivingSession(message);
1109		keyTransportMessage = message.getParameters(session, getOwnDeviceId());
1110
1111		if (session.isFresh() && keyTransportMessage != null) {
1112			putFreshSession(session);
1113		}
1114
1115		return keyTransportMessage;
1116	}
1117
1118	private void putFreshSession(XmppAxolotlSession session) {
1119		Log.d(Config.LOGTAG,"put fresh session");
1120		sessions.put(session);
1121		if (Config.X509_VERIFICATION) {
1122			if (session.getIdentityKey() != null) {
1123				verifySessionWithPEP(session);
1124			} else {
1125				Log.e(Config.LOGTAG,account.getJid().toBareJid()+": identity key was empty after reloading for x509 verification");
1126			}
1127		}
1128	}
1129}