path: root/src/main/java/eu/siacs/conversations/crypto/axolotl/AxolotlService.java

package eu.siacs.conversations.crypto.axolotl;

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.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().getFeatures().pep()) {
			publishBundlesIfNeeded(true, false);
		} else {
			Log.d(Config.LOGTAG,account.getJid().toBareJid()+": skipping OMEMO initialization");
		}
	}

	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, AxolotlService.getLogprefix(account) + "Building session for remote address: " + axolotlAddress.toString());
				String fingerprint = store.loadSession(axolotlAddress).getSessionState().getRemoteIdentityKey().getFingerprint().replaceAll("\\s", "");
				this.put(axolotlAddress, new XmppAxolotlSession(account, store, axolotlAddress, fingerprint));
			}
		}

		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);
		}
	}

	public enum FetchStatus {
		PENDING,
		SUCCESS,
		SUCCESS_VERIFIED,
		TIMEOUT,
		ERROR
	}

	private static class FetchStatusMap extends AxolotlAddressMap<FetchStatus> {

	}

	public static String getLogprefix(Account account) {
		return LOGPREFIX + " (" + account.getJid().toBareJid().toString() + "): ";
	}

	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", "");
	}

	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);
			}
		}
	}

	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);
	}

	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!
			}
		});
	}

	public void purgeKey(final String fingerprint) {
		axolotlStore.setFingerprintTrust(fingerprint.replaceAll("\\s", ""), XmppAxolotlSession.Trust.COMPROMISED);
	}

	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);
					}
				}
			}
		});
	}

	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"));
					}
				}
			});
		}
	}

	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();
		}
	}

	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());
				}
			}
		});
	}

	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"));
				}
			}
		});
	}

	public boolean isContactAxolotlCapable(Contact contact) {
		Jid jid = contact.getJid().toBareJid();
		return hasAny(contact) ||
				(deviceIds.containsKey(jid) && !deviceIds.get(jid).isEmpty());
	}

	public XmppAxolotlSession.Trust getFingerprintTrust(String fingerprint) {
		return axolotlStore.getFingerprintTrust(fingerprint);
	}

	public void setFingerprintTrust(String fingerprint, XmppAxolotlSession.Trust trust) {
		axolotlStore.setFingerprintTrust(fingerprint, trust);
	}

	private void verifySessionWithPEP(final XmppAxolotlSession session, final IdentityKey identityKey) {
		final AxolotlAddress address = session.getRemoteAddress();
		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");
									Log.d(Config.LOGTAG, "verified session with x.509 signature. fingerprint was: "+session.getFingerprint());
									setFingerprintTrust(session.getFingerprint(), XmppAxolotlSession.Trust.TRUSTED_X509);
									fetchStatusMap.put(address, FetchStatus.SUCCESS_VERIFIED);
									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());
						}
					}
					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, 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().getFingerprint().replaceAll("\\s", ""));
							sessions.put(address, session);
							if (Config.X509_VERIFICATION) {
								verifySessionWithPEP(session, bundle.getIdentityKey());
							} 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());
		}
	}

	public Set<AxolotlAddress> findDevicesWithoutSession(final Conversation conversation) {
		return findDevicesWithoutSession(conversation.getContact().getJid().toBareJid());
	}

	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.getFingerprint().replaceAll("\\s", ""));
						sessions.put(address, session);
					} else {
						Log.d(Config.LOGTAG, AxolotlService.getLogprefix(account) + "Found device " + account.getJid().toBareJid() + ":" + 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.getFingerprint().replaceAll("\\s", ""));
						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;
	}

	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;
	}

	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;
	}

	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, 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;
	}

	@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;
	}

	private XmppAxolotlSession recreateUncachedSession(AxolotlAddress address) {
		IdentityKey identityKey = axolotlStore.loadSession(address).getSessionState().getRemoteIdentityKey();
		return (identityKey != null)
				? new XmppAxolotlSession(account, axolotlStore, address,
						identityKey.getFingerprint().replaceAll("\\s", ""))
				: 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, 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) {
			sessions.put(session);
		}

		return plaintextMessage;
	}

	public XmppAxolotlMessage.XmppAxolotlKeyTransportMessage processReceivingKeyTransportMessage(XmppAxolotlMessage message) {
		XmppAxolotlMessage.XmppAxolotlKeyTransportMessage keyTransportMessage;

		XmppAxolotlSession session = getReceivingSession(message);
		keyTransportMessage = message.getParameters(session, getOwnDeviceId());

		if (session.isFresh() && keyTransportMessage != null) {
			sessions.put(session);
		}

		return keyTransportMessage;
	}
}