]> nmode's Git Repositories - signal-cli/blobdiff - src/main/java/org/asamk/signal/Manager.java
Update signal-service-java dependency
[signal-cli] / src / main / java / org / asamk / signal / Manager.java
index d626ccaf4c583a33b33453e96ed81a948c0848f0..8e478d78d556df5a11c76f1260c6fff6d701af49 100644 (file)
@@ -18,17 +18,34 @@ package org.asamk.signal;
 
 import com.fasterxml.jackson.annotation.JsonAutoDetect;
 import com.fasterxml.jackson.annotation.PropertyAccessor;
+import com.fasterxml.jackson.core.JsonGenerator;
+import com.fasterxml.jackson.core.JsonParser;
 import com.fasterxml.jackson.databind.DeserializationFeature;
 import com.fasterxml.jackson.databind.JsonNode;
 import com.fasterxml.jackson.databind.ObjectMapper;
 import com.fasterxml.jackson.databind.SerializationFeature;
 import com.fasterxml.jackson.databind.node.ObjectNode;
+import org.apache.http.util.TextUtils;
 import org.asamk.Signal;
+import org.asamk.signal.storage.contacts.ContactInfo;
+import org.asamk.signal.storage.contacts.JsonContactsStore;
+import org.asamk.signal.storage.groups.GroupInfo;
+import org.asamk.signal.storage.groups.JsonGroupStore;
+import org.asamk.signal.storage.protocol.JsonIdentityKeyStore;
+import org.asamk.signal.storage.protocol.JsonSignalProtocolStore;
+import org.asamk.signal.storage.threads.JsonThreadStore;
+import org.asamk.signal.storage.threads.ThreadInfo;
+import org.asamk.signal.util.KeyUtils;
+import org.asamk.signal.util.Util;
+import org.signal.libsignal.metadata.*;
+import org.signal.libsignal.metadata.certificate.CertificateValidator;
 import org.whispersystems.libsignal.*;
 import org.whispersystems.libsignal.ecc.Curve;
 import org.whispersystems.libsignal.ecc.ECKeyPair;
+import org.whispersystems.libsignal.ecc.ECPublicKey;
+import org.whispersystems.libsignal.fingerprint.Fingerprint;
+import org.whispersystems.libsignal.fingerprint.NumericFingerprintGenerator;
 import org.whispersystems.libsignal.state.PreKeyRecord;
-import org.whispersystems.libsignal.state.SignalProtocolStore;
 import org.whispersystems.libsignal.state.SignedPreKeyRecord;
 import org.whispersystems.libsignal.util.KeyHelper;
 import org.whispersystems.libsignal.util.Medium;
@@ -37,27 +54,60 @@ import org.whispersystems.signalservice.api.SignalServiceAccountManager;
 import org.whispersystems.signalservice.api.SignalServiceMessagePipe;
 import org.whispersystems.signalservice.api.SignalServiceMessageReceiver;
 import org.whispersystems.signalservice.api.SignalServiceMessageSender;
-import org.whispersystems.signalservice.api.crypto.*;
+import org.whispersystems.signalservice.api.crypto.SignalServiceCipher;
+import org.whispersystems.signalservice.api.crypto.UnidentifiedAccess;
+import org.whispersystems.signalservice.api.crypto.UnidentifiedAccessPair;
 import org.whispersystems.signalservice.api.crypto.UntrustedIdentityException;
 import org.whispersystems.signalservice.api.messages.*;
-import org.whispersystems.signalservice.api.messages.multidevice.SignalServiceSyncMessage;
+import org.whispersystems.signalservice.api.messages.multidevice.*;
+import org.whispersystems.signalservice.api.push.ContactTokenDetails;
 import org.whispersystems.signalservice.api.push.SignalServiceAddress;
 import org.whispersystems.signalservice.api.push.TrustStore;
 import org.whispersystems.signalservice.api.push.exceptions.AuthorizationFailedException;
 import org.whispersystems.signalservice.api.push.exceptions.EncapsulatedExceptions;
+import org.whispersystems.signalservice.api.push.exceptions.NetworkFailureException;
+import org.whispersystems.signalservice.api.push.exceptions.UnregisteredUserException;
 import org.whispersystems.signalservice.api.util.InvalidNumberException;
 import org.whispersystems.signalservice.api.util.PhoneNumberFormatter;
+import org.whispersystems.signalservice.api.util.SleepTimer;
+import org.whispersystems.signalservice.api.util.UptimeSleepTimer;
+import org.whispersystems.signalservice.internal.configuration.SignalCdnUrl;
+import org.whispersystems.signalservice.internal.configuration.SignalContactDiscoveryUrl;
+import org.whispersystems.signalservice.internal.configuration.SignalServiceConfiguration;
+import org.whispersystems.signalservice.internal.configuration.SignalServiceUrl;
+import org.whispersystems.signalservice.internal.push.SignalServiceProtos;
+import org.whispersystems.signalservice.internal.util.Base64;
 
 import java.io.*;
+import java.net.URI;
+import java.net.URISyntaxException;
+import java.net.URLDecoder;
+import java.net.URLEncoder;
+import java.nio.channels.Channels;
+import java.nio.channels.FileChannel;
+import java.nio.channels.FileLock;
 import java.nio.file.Files;
+import java.nio.file.Path;
 import java.nio.file.Paths;
+import java.nio.file.StandardCopyOption;
+import java.nio.file.attribute.PosixFilePermission;
+import java.nio.file.attribute.PosixFilePermissions;
 import java.util.*;
 import java.util.concurrent.TimeUnit;
 import java.util.concurrent.TimeoutException;
 
+import static java.nio.file.attribute.PosixFilePermission.*;
+
 class Manager implements Signal {
     private final static String URL = "https://textsecure-service.whispersystems.org";
+    private final static String CDN_URL = "https://cdn.signal.org";
     private final static TrustStore TRUST_STORE = new WhisperTrustStore();
+    private final static SignalServiceConfiguration serviceConfiguration = new SignalServiceConfiguration(
+            new SignalServiceUrl[]{new SignalServiceUrl(URL, TRUST_STORE)},
+            new SignalCdnUrl[]{new SignalCdnUrl(CDN_URL, TRUST_STORE)},
+            new SignalContactDiscoveryUrl[0]
+    );
+    private final static String UNIDENTIFIED_SENDER_TRUST_ROOT = "BXu6QIKVz5MA8gstzfOgRQGqyLqOwNKHL6INkv3IHWMF";
 
     public final static String PROJECT_NAME = Manager.class.getPackage().getImplementationTitle();
     public final static String PROJECT_VERSION = Manager.class.getPackage().getImplementationVersion();
@@ -65,42 +115,108 @@ class Manager implements Signal {
 
     private final static int PREKEY_MINIMUM_COUNT = 20;
     private static final int PREKEY_BATCH_SIZE = 100;
+    private static final int MAX_ATTACHMENT_SIZE = 150 * 1024 * 1024;
 
     private final String settingsPath;
     private final String dataPath;
     private final String attachmentsPath;
+    private final String avatarsPath;
+
+    private FileChannel fileChannel;
+    private FileLock lock;
 
-    private final ObjectMapper jsonProcessot = new ObjectMapper();
+    private final ObjectMapper jsonProcessor = new ObjectMapper();
     private String username;
+    private int deviceId = SignalServiceAddress.DEFAULT_DEVICE_ID;
+    private boolean isMultiDevice = false;
     private String password;
+    private String registrationLockPin;
     private String signalingKey;
+    private byte[] profileKey;
     private int preKeyIdOffset;
     private int nextSignedPreKeyId;
 
     private boolean registered = false;
 
-    private SignalProtocolStore signalProtocolStore;
+    private JsonSignalProtocolStore signalProtocolStore;
     private SignalServiceAccountManager accountManager;
     private JsonGroupStore groupStore;
+    private JsonContactsStore contactStore;
+    private JsonThreadStore threadStore;
+    private SignalServiceMessagePipe messagePipe = null;
+    private SignalServiceMessagePipe unidentifiedMessagePipe = null;
+
+    private SleepTimer timer = new UptimeSleepTimer();
 
     public Manager(String username, String settingsPath) {
         this.username = username;
         this.settingsPath = settingsPath;
         this.dataPath = this.settingsPath + "/data";
         this.attachmentsPath = this.settingsPath + "/attachments";
+        this.avatarsPath = this.settingsPath + "/avatars";
+
+        jsonProcessor.setVisibility(PropertyAccessor.ALL, JsonAutoDetect.Visibility.NONE); // disable autodetect
+        jsonProcessor.enable(SerializationFeature.INDENT_OUTPUT); // for pretty print, you can disable it.
+        jsonProcessor.enable(SerializationFeature.WRITE_NULL_MAP_VALUES);
+        jsonProcessor.disable(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES);
+        jsonProcessor.disable(JsonParser.Feature.AUTO_CLOSE_SOURCE);
+        jsonProcessor.disable(JsonGenerator.Feature.AUTO_CLOSE_TARGET);
+    }
+
+    public String getUsername() {
+        return username;
+    }
+
+    private IdentityKey getIdentity() {
+        return signalProtocolStore.getIdentityKeyPair().getPublicKey();
+    }
 
-        jsonProcessot.setVisibility(PropertyAccessor.ALL, JsonAutoDetect.Visibility.NONE); // disable autodetect
-        jsonProcessot.enable(SerializationFeature.INDENT_OUTPUT); // for pretty print, you can disable it.
-        jsonProcessot.enable(SerializationFeature.WRITE_NULL_MAP_VALUES);
-        jsonProcessot.disable(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES);
+    public int getDeviceId() {
+        return deviceId;
     }
 
     public String getFileName() {
-        new File(dataPath).mkdirs();
         return dataPath + "/" + username;
     }
 
+    private String getMessageCachePath() {
+        return this.dataPath + "/" + username + ".d/msg-cache";
+    }
+
+    private String getMessageCachePath(String sender) {
+        return getMessageCachePath() + "/" + sender.replace("/", "_");
+    }
+
+    private File getMessageCacheFile(String sender, long now, long timestamp) throws IOException {
+        String cachePath = getMessageCachePath(sender);
+        createPrivateDirectories(cachePath);
+        return new File(cachePath + "/" + now + "_" + timestamp);
+    }
+
+    private static void createPrivateDirectories(String path) throws IOException {
+        final Path file = new File(path).toPath();
+        try {
+            Set<PosixFilePermission> perms = EnumSet.of(OWNER_READ, OWNER_WRITE, OWNER_EXECUTE);
+            Files.createDirectories(file, PosixFilePermissions.asFileAttribute(perms));
+        } catch (UnsupportedOperationException e) {
+            Files.createDirectories(file);
+        }
+    }
+
+    private static void createPrivateFile(String path) throws IOException {
+        final Path file = new File(path).toPath();
+        try {
+            Set<PosixFilePermission> perms = EnumSet.of(OWNER_READ, OWNER_WRITE);
+            Files.createFile(file, PosixFilePermissions.asFileAttribute(perms));
+        } catch (UnsupportedOperationException e) {
+            Files.createFile(file);
+        }
+    }
+
     public boolean userExists() {
+        if (username == null) {
+            return false;
+        }
         File f = new File(getFileName());
         return !(!f.exists() || f.isDirectory());
     }
@@ -118,11 +234,51 @@ class Manager implements Signal {
         return node;
     }
 
-    public void load() throws IOException, InvalidKeyException {
-        JsonNode rootNode = jsonProcessot.readTree(new File(getFileName()));
+    private void openFileChannel() throws IOException {
+        if (fileChannel != null)
+            return;
+
+        createPrivateDirectories(dataPath);
+        if (!new File(getFileName()).exists()) {
+            createPrivateFile(getFileName());
+        }
+        fileChannel = new RandomAccessFile(new File(getFileName()), "rw").getChannel();
+        lock = fileChannel.tryLock();
+        if (lock == null) {
+            System.err.println("Config file is in use by another instance, waiting…");
+            lock = fileChannel.lock();
+            System.err.println("Config file lock acquired.");
+        }
+    }
+
+    public void init() throws IOException {
+        load();
+
+        migrateLegacyConfigs();
+
+        accountManager = new SignalServiceAccountManager(serviceConfiguration, username, password, deviceId, USER_AGENT, timer);
+        try {
+            if (registered && accountManager.getPreKeysCount() < PREKEY_MINIMUM_COUNT) {
+                refreshPreKeys();
+                save();
+            }
+        } catch (AuthorizationFailedException e) {
+            System.err.println("Authorization failed, was the number registered elsewhere?");
+        }
+    }
+
+    private void load() throws IOException {
+        openFileChannel();
+        JsonNode rootNode = jsonProcessor.readTree(Channels.newInputStream(fileChannel));
 
+        JsonNode node = rootNode.get("deviceId");
+        if (node != null) {
+            deviceId = node.asInt();
+        }
         username = getNotNullNode(rootNode, "username").asText();
         password = getNotNullNode(rootNode, "password").asText();
+        JsonNode pinNode = rootNode.get("registrationLockPin");
+        registrationLockPin = pinNode == null ? null : pinNode.asText();
         if (rootNode.has("signalingKey")) {
             signalingKey = getNotNullNode(rootNode, "signalingKey").asText();
         }
@@ -136,39 +292,84 @@ class Manager implements Signal {
         } else {
             nextSignedPreKeyId = 0;
         }
-        signalProtocolStore = jsonProcessot.convertValue(getNotNullNode(rootNode, "axolotlStore"), JsonSignalProtocolStore.class);
+        if (rootNode.has("profileKey")) {
+            profileKey = Base64.decode(getNotNullNode(rootNode, "profileKey").asText());
+        } else {
+            // Old config file, creating new profile key
+            profileKey = KeyUtils.createProfileKey();
+        }
+
+        signalProtocolStore = jsonProcessor.convertValue(getNotNullNode(rootNode, "axolotlStore"), JsonSignalProtocolStore.class);
         registered = getNotNullNode(rootNode, "registered").asBoolean();
         JsonNode groupStoreNode = rootNode.get("groupStore");
         if (groupStoreNode != null) {
-            groupStore = jsonProcessot.convertValue(groupStoreNode, JsonGroupStore.class);
+            groupStore = jsonProcessor.convertValue(groupStoreNode, JsonGroupStore.class);
         }
         if (groupStore == null) {
             groupStore = new JsonGroupStore();
         }
-        accountManager = new SignalServiceAccountManager(URL, TRUST_STORE, username, password, USER_AGENT);
-        try {
-            if (registered && accountManager.getPreKeysCount() < PREKEY_MINIMUM_COUNT) {
-                refreshPreKeys();
-                save();
+
+        JsonNode contactStoreNode = rootNode.get("contactStore");
+        if (contactStoreNode != null) {
+            contactStore = jsonProcessor.convertValue(contactStoreNode, JsonContactsStore.class);
+        }
+        if (contactStore == null) {
+            contactStore = new JsonContactsStore();
+        }
+        JsonNode threadStoreNode = rootNode.get("threadStore");
+        if (threadStoreNode != null) {
+            threadStore = jsonProcessor.convertValue(threadStoreNode, JsonThreadStore.class);
+        }
+        if (threadStore == null) {
+            threadStore = new JsonThreadStore();
+        }
+    }
+
+    private void migrateLegacyConfigs() {
+        // Copy group avatars that were previously stored in the attachments folder
+        // to the new avatar folder
+        if (JsonGroupStore.groupsWithLegacyAvatarId.size() > 0) {
+            for (GroupInfo g : JsonGroupStore.groupsWithLegacyAvatarId) {
+                File avatarFile = getGroupAvatarFile(g.groupId);
+                File attachmentFile = getAttachmentFile(g.getAvatarId());
+                if (!avatarFile.exists() && attachmentFile.exists()) {
+                    try {
+                        createPrivateDirectories(avatarsPath);
+                        Files.copy(attachmentFile.toPath(), avatarFile.toPath(), StandardCopyOption.REPLACE_EXISTING);
+                    } catch (Exception e) {
+                        // Ignore
+                    }
+                }
             }
-        } catch (AuthorizationFailedException e) {
-            System.err.println("Authorization failed, was the number registered elsewhere?");
+            JsonGroupStore.groupsWithLegacyAvatarId.clear();
+            save();
         }
     }
 
     private void save() {
-        ObjectNode rootNode = jsonProcessot.createObjectNode();
+        if (username == null) {
+            return;
+        }
+        ObjectNode rootNode = jsonProcessor.createObjectNode();
         rootNode.put("username", username)
+                .put("deviceId", deviceId)
                 .put("password", password)
+                .put("registrationLockPin", registrationLockPin)
                 .put("signalingKey", signalingKey)
                 .put("preKeyIdOffset", preKeyIdOffset)
                 .put("nextSignedPreKeyId", nextSignedPreKeyId)
                 .put("registered", registered)
                 .putPOJO("axolotlStore", signalProtocolStore)
                 .putPOJO("groupStore", groupStore)
+                .putPOJO("contactStore", contactStore)
+                .putPOJO("threadStore", threadStore)
         ;
         try {
-            jsonProcessot.writeValue(new File(getFileName()), rootNode);
+            openFileChannel();
+            fileChannel.position(0);
+            jsonProcessor.writeValue(Channels.newOutputStream(fileChannel), rootNode);
+            fileChannel.truncate(fileChannel.position());
+            fileChannel.force(false);
         } catch (Exception e) {
             System.err.println(String.format("Error saving file: %s", e.getMessage()));
         }
@@ -187,12 +388,12 @@ class Manager implements Signal {
         return registered;
     }
 
-    public void register(boolean voiceVerication) throws IOException {
-        password = Util.getSecret(18);
+    public void register(boolean voiceVerification) throws IOException {
+        password = KeyUtils.createPassword();
 
-        accountManager = new SignalServiceAccountManager(URL, TRUST_STORE, username, password, USER_AGENT);
+        accountManager = new SignalServiceAccountManager(serviceConfiguration, username, password, USER_AGENT, timer);
 
-        if (voiceVerication)
+        if (voiceVerification)
             accountManager.requestVoiceVerificationCode();
         else
             accountManager.requestSmsVerificationCode();
@@ -201,6 +402,107 @@ class Manager implements Signal {
         save();
     }
 
+    public void updateAccountAttributes() throws IOException {
+        accountManager.setAccountAttributes(signalingKey, signalProtocolStore.getLocalRegistrationId(), true, registrationLockPin, getSelfUnidentifiedAccessKey(), false);
+    }
+
+    public void unregister() throws IOException {
+        // When setting an empty GCM id, the Signal-Server also sets the fetchesMessages property to false.
+        // If this is the master device, other users can't send messages to this number anymore.
+        // If this is a linked device, other users can still send messages, but this device doesn't receive them anymore.
+        accountManager.setGcmId(Optional.<String>absent());
+    }
+
+    public URI getDeviceLinkUri() throws TimeoutException, IOException {
+        password = KeyUtils.createPassword();
+
+        accountManager = new SignalServiceAccountManager(serviceConfiguration, username, password, USER_AGENT, timer);
+        String uuid = accountManager.getNewDeviceUuid();
+
+        registered = false;
+        try {
+            return new URI("tsdevice:/?uuid=" + URLEncoder.encode(uuid, "utf-8") + "&pub_key=" + URLEncoder.encode(Base64.encodeBytesWithoutPadding(signalProtocolStore.getIdentityKeyPair().getPublicKey().serialize()), "utf-8"));
+        } catch (URISyntaxException e) {
+            // Shouldn't happen
+            return null;
+        }
+    }
+
+    public void finishDeviceLink(String deviceName) throws IOException, InvalidKeyException, TimeoutException, UserAlreadyExists {
+        signalingKey = KeyUtils.createSignalingKey();
+        SignalServiceAccountManager.NewDeviceRegistrationReturn ret = accountManager.finishNewDeviceRegistration(signalProtocolStore.getIdentityKeyPair(), signalingKey, false, true, signalProtocolStore.getLocalRegistrationId(), deviceName);
+        deviceId = ret.getDeviceId();
+        username = ret.getNumber();
+        // TODO do this check before actually registering
+        if (userExists()) {
+            throw new UserAlreadyExists(username, getFileName());
+        }
+        signalProtocolStore = new JsonSignalProtocolStore(ret.getIdentity(), signalProtocolStore.getLocalRegistrationId());
+
+        registered = true;
+        isMultiDevice = true;
+        refreshPreKeys();
+
+        requestSyncGroups();
+        requestSyncContacts();
+
+        save();
+    }
+
+    public List<DeviceInfo> getLinkedDevices() throws IOException {
+        List<DeviceInfo> devices = accountManager.getDevices();
+        isMultiDevice = devices.size() > 1;
+        return devices;
+    }
+
+    public void removeLinkedDevices(int deviceId) throws IOException {
+        accountManager.removeDevice(deviceId);
+    }
+
+    public static Map<String, String> getQueryMap(String query) {
+        String[] params = query.split("&");
+        Map<String, String> map = new HashMap<>();
+        for (String param : params) {
+            String name = null;
+            final String[] paramParts = param.split("=");
+            try {
+                name = URLDecoder.decode(paramParts[0], "utf-8");
+            } catch (UnsupportedEncodingException e) {
+                // Impossible
+            }
+            String value = null;
+            try {
+                value = URLDecoder.decode(paramParts[1], "utf-8");
+            } catch (UnsupportedEncodingException e) {
+                // Impossible
+            }
+            map.put(name, value);
+        }
+        return map;
+    }
+
+    public void addDeviceLink(URI linkUri) throws IOException, InvalidKeyException {
+        Map<String, String> query = getQueryMap(linkUri.getRawQuery());
+        String deviceIdentifier = query.get("uuid");
+        String publicKeyEncoded = query.get("pub_key");
+
+        if (TextUtils.isEmpty(deviceIdentifier) || TextUtils.isEmpty(publicKeyEncoded)) {
+            throw new RuntimeException("Invalid device link uri");
+        }
+
+        ECPublicKey deviceKey = Curve.decodePoint(Base64.decode(publicKeyEncoded), 0);
+
+        addDevice(deviceIdentifier, deviceKey);
+    }
+
+    private void addDevice(String deviceIdentifier, ECPublicKey deviceKey) throws IOException, InvalidKeyException {
+        IdentityKeyPair identityKeyPair = signalProtocolStore.getIdentityKeyPair();
+        String verificationCode = accountManager.getNewDeviceVerificationCode();
+
+        accountManager.addDevice(deviceIdentifier, deviceKey, identityKeyPair, Optional.of(profileKey), verificationCode);
+        isMultiDevice = true;
+    }
+
     private List<PreKeyRecord> generatePreKeys() {
         List<PreKeyRecord> records = new LinkedList<>();
 
@@ -219,24 +521,6 @@ class Manager implements Signal {
         return records;
     }
 
-    private PreKeyRecord getOrGenerateLastResortPreKey() {
-        if (signalProtocolStore.containsPreKey(Medium.MAX_VALUE)) {
-            try {
-                return signalProtocolStore.loadPreKey(Medium.MAX_VALUE);
-            } catch (InvalidKeyIdException e) {
-                signalProtocolStore.removePreKey(Medium.MAX_VALUE);
-            }
-        }
-
-        ECKeyPair keyPair = Curve.generateKeyPair();
-        PreKeyRecord record = new PreKeyRecord(Medium.MAX_VALUE, keyPair);
-
-        signalProtocolStore.storePreKey(Medium.MAX_VALUE, record);
-        save();
-
-        return record;
-    }
-
     private SignedPreKeyRecord generateSignedPreKey(IdentityKeyPair identityKeyPair) {
         try {
             ECKeyPair keyPair = Curve.generateKeyPair();
@@ -253,24 +537,33 @@ class Manager implements Signal {
         }
     }
 
-    public void verifyAccount(String verificationCode) throws IOException {
+    public void verifyAccount(String verificationCode, String pin) throws IOException {
         verificationCode = verificationCode.replace("-", "");
-        signalingKey = Util.getSecret(52);
-        accountManager.verifyAccountWithCode(verificationCode, signalingKey, signalProtocolStore.getLocalRegistrationId(), false, true);
+        signalingKey = KeyUtils.createSignalingKey();
+        accountManager.verifyAccountWithCode(verificationCode, signalingKey, signalProtocolStore.getLocalRegistrationId(), true, pin, getSelfUnidentifiedAccessKey(), false);
 
         //accountManager.setGcmId(Optional.of(GoogleCloudMessaging.getInstance(this).register(REGISTRATION_ID)));
         registered = true;
+        registrationLockPin = pin;
 
         refreshPreKeys();
         save();
     }
 
+    public void setRegistrationLockPin(Optional<String> pin) throws IOException {
+        accountManager.setPin(pin);
+        if (pin.isPresent()) {
+            registrationLockPin = pin.get();
+        } else {
+            registrationLockPin = null;
+        }
+    }
+
     private void refreshPreKeys() throws IOException {
         List<PreKeyRecord> oneTimePreKeys = generatePreKeys();
-        PreKeyRecord lastResortKey = getOrGenerateLastResortPreKey();
         SignedPreKeyRecord signedPreKeyRecord = generateSignedPreKey(signalProtocolStore.getIdentityKeyPair());
 
-        accountManager.setPreKeys(signalProtocolStore.getIdentityKeyPair().getPublicKey(), lastResortKey, signedPreKeyRecord, oneTimePreKeys);
+        accountManager.setPreKeys(signalProtocolStore.getIdentityKeyPair().getPublicKey(), signedPreKeyRecord, oneTimePreKeys);
     }
 
 
@@ -280,7 +573,7 @@ class Manager implements Signal {
             SignalServiceAttachments = new ArrayList<>(attachments.size());
             for (String attachment : attachments) {
                 try {
-                    SignalServiceAttachments.add(createAttachment(attachment));
+                    SignalServiceAttachments.add(createAttachment(new File(attachment)));
                 } catch (IOException e) {
                     throw new AttachmentInvalidException(attachment, e);
                 }
@@ -289,18 +582,58 @@ class Manager implements Signal {
         return SignalServiceAttachments;
     }
 
-    private static SignalServiceAttachmentStream createAttachment(String attachment) throws IOException {
-        File attachmentFile = new File(attachment);
+    private static SignalServiceAttachmentStream createAttachment(File attachmentFile) throws IOException {
         InputStream attachmentStream = new FileInputStream(attachmentFile);
         final long attachmentSize = attachmentFile.length();
-        String mime = Files.probeContentType(Paths.get(attachment));
-        return new SignalServiceAttachmentStream(attachmentStream, mime, attachmentSize, null);
+        String mime = Files.probeContentType(attachmentFile.toPath());
+        if (mime == null) {
+            mime = "application/octet-stream";
+        }
+        // TODO mabybe add a parameter to set the voiceNote, preview, width, height and caption option
+        Optional<byte[]> preview = Optional.absent();
+        Optional<String> caption = Optional.absent();
+        return new SignalServiceAttachmentStream(attachmentStream, mime, attachmentSize, Optional.of(attachmentFile.getName()), false, preview, 0, 0, caption, null);
+    }
+
+    private Optional<SignalServiceAttachmentStream> createGroupAvatarAttachment(byte[] groupId) throws IOException {
+        File file = getGroupAvatarFile(groupId);
+        if (!file.exists()) {
+            return Optional.absent();
+        }
+
+        return Optional.of(createAttachment(file));
+    }
+
+    private Optional<SignalServiceAttachmentStream> createContactAvatarAttachment(String number) throws IOException {
+        File file = getContactAvatarFile(number);
+        if (!file.exists()) {
+            return Optional.absent();
+        }
+
+        return Optional.of(createAttachment(file));
+    }
+
+    private GroupInfo getGroupForSending(byte[] groupId) throws GroupNotFoundException, NotAGroupMemberException {
+        GroupInfo g = groupStore.getGroup(groupId);
+        if (g == null) {
+            throw new GroupNotFoundException(groupId);
+        }
+        for (String member : g.members) {
+            if (member.equals(this.username)) {
+                return g;
+            }
+        }
+        throw new NotAGroupMemberException(groupId, g.name);
+    }
+
+    public List<GroupInfo> getGroups() {
+        return groupStore.getGroups();
     }
 
     @Override
     public void sendGroupMessage(String messageText, List<String> attachments,
                                  byte[] groupId)
-            throws IOException, EncapsulatedExceptions, GroupNotFoundException, AttachmentInvalidException, UntrustedIdentityException {
+            throws IOException, EncapsulatedExceptions, GroupNotFoundException, AttachmentInvalidException {
         final SignalServiceDataMessage.Builder messageBuilder = SignalServiceDataMessage.newBuilder().withBody(messageText);
         if (attachments != null) {
             messageBuilder.withAttachments(getSignalServiceAttachments(attachments));
@@ -311,31 +644,54 @@ class Manager implements Signal {
                     .build();
             messageBuilder.asGroupMessage(group);
         }
-        SignalServiceDataMessage message = messageBuilder.build();
+        ThreadInfo thread = threadStore.getThread(Base64.encodeBytes(groupId));
+        if (thread != null) {
+            messageBuilder.withExpiration(thread.messageExpirationTime);
+        }
 
-        sendMessage(message, groupStore.getGroup(groupId).members);
+        final GroupInfo g = getGroupForSending(groupId);
+
+        // Don't send group message to ourself
+        final List<String> membersSend = new ArrayList<>(g.members);
+        membersSend.remove(this.username);
+        sendMessageLegacy(messageBuilder, membersSend);
     }
 
-    public void sendQuitGroupMessage(byte[] groupId) throws GroupNotFoundException, IOException, EncapsulatedExceptions, UntrustedIdentityException {
+    public void sendQuitGroupMessage(byte[] groupId) throws GroupNotFoundException, IOException, EncapsulatedExceptions {
         SignalServiceGroup group = SignalServiceGroup.newBuilder(SignalServiceGroup.Type.QUIT)
                 .withId(groupId)
                 .build();
 
-        SignalServiceDataMessage message = SignalServiceDataMessage.newBuilder()
-                .asGroupMessage(group)
-                .build();
+        SignalServiceDataMessage.Builder messageBuilder = SignalServiceDataMessage.newBuilder()
+                .asGroupMessage(group);
 
-        sendMessage(message, groupStore.getGroup(groupId).members);
+        final GroupInfo g = getGroupForSending(groupId);
+        g.members.remove(this.username);
+        groupStore.updateGroup(g);
+
+        sendMessageLegacy(messageBuilder, g.members);
     }
 
-    public byte[] sendUpdateGroupMessage(byte[] groupId, String name, Collection<String> members, String avatarFile) throws IOException, EncapsulatedExceptions, GroupNotFoundException, AttachmentInvalidException, UntrustedIdentityException {
+    private static String join(CharSequence separator, Iterable<? extends CharSequence> list) {
+        StringBuilder buf = new StringBuilder();
+        for (CharSequence str : list) {
+            if (buf.length() > 0) {
+                buf.append(separator);
+            }
+            buf.append(str);
+        }
+
+        return buf.toString();
+    }
+
+    public byte[] sendUpdateGroupMessage(byte[] groupId, String name, Collection<String> members, String avatarFile) throws IOException, EncapsulatedExceptions, GroupNotFoundException, AttachmentInvalidException {
         GroupInfo g;
         if (groupId == null) {
             // Create new group
-            g = new GroupInfo(Util.getSecretBytes(16));
+            g = new GroupInfo(KeyUtils.createGroupId());
             g.members.add(username);
         } else {
-            g = groupStore.getGroup(groupId);
+            g = getGroupForSending(groupId);
         }
 
         if (name != null) {
@@ -343,45 +699,107 @@ class Manager implements Signal {
         }
 
         if (members != null) {
+            Set<String> newMembers = new HashSet<>();
             for (String member : members) {
                 try {
-                    g.members.add(canonicalizeNumber(member));
+                    member = canonicalizeNumber(member);
                 } catch (InvalidNumberException e) {
                     System.err.println("Failed to add member \"" + member + "\" to group: " + e.getMessage());
                     System.err.println("Aborting…");
                     System.exit(1);
                 }
+                if (g.members.contains(member)) {
+                    continue;
+                }
+                newMembers.add(member);
+                g.members.add(member);
             }
+            final List<ContactTokenDetails> contacts = accountManager.getContacts(newMembers);
+            if (contacts.size() != newMembers.size()) {
+                // Some of the new members are not registered on Signal
+                for (ContactTokenDetails contact : contacts) {
+                    newMembers.remove(contact.getNumber());
+                }
+                System.err.println("Failed to add members " + join(", ", newMembers) + " to group: Not registered on Signal");
+                System.err.println("Aborting…");
+                System.exit(1);
+            }
+        }
+
+        if (avatarFile != null) {
+            createPrivateDirectories(avatarsPath);
+            File aFile = getGroupAvatarFile(g.groupId);
+            Files.copy(Paths.get(avatarFile), aFile.toPath(), StandardCopyOption.REPLACE_EXISTING);
+        }
+
+        groupStore.updateGroup(g);
+
+        SignalServiceDataMessage.Builder messageBuilder = getGroupUpdateMessageBuilder(g);
+
+        // Don't send group message to ourself
+        final List<String> membersSend = new ArrayList<>(g.members);
+        membersSend.remove(this.username);
+        sendMessageLegacy(messageBuilder, membersSend);
+        return g.groupId;
+    }
+
+    private void sendUpdateGroupMessage(byte[] groupId, String recipient) throws IOException, EncapsulatedExceptions {
+        if (groupId == null) {
+            return;
+        }
+        GroupInfo g = getGroupForSending(groupId);
+
+        if (!g.members.contains(recipient)) {
+            return;
         }
 
+        SignalServiceDataMessage.Builder messageBuilder = getGroupUpdateMessageBuilder(g);
+
+        // Send group message only to the recipient who requested it
+        final List<String> membersSend = new ArrayList<>();
+        membersSend.add(recipient);
+        sendMessageLegacy(messageBuilder, membersSend);
+    }
+
+    private SignalServiceDataMessage.Builder getGroupUpdateMessageBuilder(GroupInfo g) {
         SignalServiceGroup.Builder group = SignalServiceGroup.newBuilder(SignalServiceGroup.Type.UPDATE)
                 .withId(g.groupId)
                 .withName(g.name)
                 .withMembers(new ArrayList<>(g.members));
 
-        if (avatarFile != null) {
+        File aFile = getGroupAvatarFile(g.groupId);
+        if (aFile.exists()) {
             try {
-                group.withAvatar(createAttachment(avatarFile));
-                // TODO
-                g.avatarId = 0;
+                group.withAvatar(createAttachment(aFile));
             } catch (IOException e) {
-                throw new AttachmentInvalidException(avatarFile, e);
+                throw new AttachmentInvalidException(aFile.toString(), e);
             }
         }
 
-        groupStore.updateGroup(g);
+        return SignalServiceDataMessage.newBuilder()
+                .asGroupMessage(group.build());
+    }
 
-        SignalServiceDataMessage message = SignalServiceDataMessage.newBuilder()
-                .asGroupMessage(group.build())
-                .build();
+    private void sendGroupInfoRequest(byte[] groupId, String recipient) throws IOException, EncapsulatedExceptions {
+        if (groupId == null) {
+            return;
+        }
 
-        sendMessage(message, g.members);
-        return g.groupId;
+        SignalServiceGroup.Builder group = SignalServiceGroup.newBuilder(SignalServiceGroup.Type.REQUEST_INFO)
+                .withId(groupId);
+
+        SignalServiceDataMessage.Builder messageBuilder = SignalServiceDataMessage.newBuilder()
+                .asGroupMessage(group.build());
+
+        // Send group info request message to the recipient who sent us a message with this groupId
+        final List<String> membersSend = new ArrayList<>();
+        membersSend.add(recipient);
+        sendMessageLegacy(messageBuilder, membersSend);
     }
 
     @Override
     public void sendMessage(String message, List<String> attachments, String recipient)
-            throws EncapsulatedExceptions, AttachmentInvalidException, IOException, UntrustedIdentityException {
+            throws EncapsulatedExceptions, AttachmentInvalidException, IOException {
         List<String> recipients = new ArrayList<>(1);
         recipients.add(recipient);
         sendMessage(message, attachments, recipients);
@@ -390,30 +808,234 @@ class Manager implements Signal {
     @Override
     public void sendMessage(String messageText, List<String> attachments,
                             List<String> recipients)
-            throws IOException, EncapsulatedExceptions, AttachmentInvalidException, UntrustedIdentityException {
+            throws IOException, EncapsulatedExceptions, AttachmentInvalidException {
         final SignalServiceDataMessage.Builder messageBuilder = SignalServiceDataMessage.newBuilder().withBody(messageText);
         if (attachments != null) {
             messageBuilder.withAttachments(getSignalServiceAttachments(attachments));
         }
-        SignalServiceDataMessage message = messageBuilder.build();
+        sendMessageLegacy(messageBuilder, recipients);
+    }
+
+    @Override
+    public void sendEndSessionMessage(List<String> recipients) throws IOException, EncapsulatedExceptions {
+        SignalServiceDataMessage.Builder messageBuilder = SignalServiceDataMessage.newBuilder()
+                .asEndSessionMessage();
 
-        sendMessage(message, recipients);
+        sendMessageLegacy(messageBuilder, recipients);
     }
 
     @Override
-    public void sendEndSessionMessage(List<String> recipients) throws IOException, EncapsulatedExceptions, UntrustedIdentityException {
-        SignalServiceDataMessage message = SignalServiceDataMessage.newBuilder()
-                .asEndSessionMessage()
-                .build();
+    public String getContactName(String number) {
+        ContactInfo contact = contactStore.getContact(number);
+        if (contact == null) {
+            return "";
+        } else {
+            return contact.name;
+        }
+    }
 
-        sendMessage(message, recipients);
+    @Override
+    public void setContactName(String number, String name) {
+        ContactInfo contact = contactStore.getContact(number);
+        if (contact == null) {
+            contact = new ContactInfo();
+            contact.number = number;
+            System.err.println("Add contact " + number + " named " + name);
+        } else {
+            System.err.println("Updating contact " + number + " name " + contact.name + " -> " + name);
+        }
+        contact.name = name;
+        contactStore.updateContact(contact);
+        save();
     }
 
-    private void sendMessage(SignalServiceDataMessage message, Collection<String> recipients)
-            throws IOException, EncapsulatedExceptions, UntrustedIdentityException {
-        SignalServiceMessageSender messageSender = new SignalServiceMessageSender(URL, TRUST_STORE, username, password,
-                signalProtocolStore, USER_AGENT, Optional.<SignalServiceMessageSender.EventListener>absent());
+    @Override
+    public List<byte[]> getGroupIds() {
+        List<GroupInfo> groups = getGroups();
+        List<byte[]> ids = new ArrayList<byte[]>(groups.size());
+        for (GroupInfo group : groups) {
+            ids.add(group.groupId);
+        }
+        return ids;
+    }
+
+    @Override
+    public String getGroupName(byte[] groupId) {
+        GroupInfo group = getGroup(groupId);
+        if (group == null) {
+            return "";
+        } else {
+            return group.name;
+        }
+    }
+
+    @Override
+    public List<String> getGroupMembers(byte[] groupId) {
+        GroupInfo group = getGroup(groupId);
+        if (group == null) {
+            return new ArrayList<String>();
+        } else {
+            return new ArrayList<String>(group.members);
+        }
+    }
+
+    @Override
+    public byte[] updateGroup(byte[] groupId, String name, List<String> members, String avatar) throws IOException, EncapsulatedExceptions, GroupNotFoundException, AttachmentInvalidException {
+        if (groupId.length == 0) {
+            groupId = null;
+        }
+        if (name.isEmpty()) {
+            name = null;
+        }
+        if (members.size() == 0) {
+            members = null;
+        }
+        if (avatar.isEmpty()) {
+            avatar = null;
+        }
+        return sendUpdateGroupMessage(groupId, name, members, avatar);
+    }
+
+    private void requestSyncGroups() throws IOException {
+        SignalServiceProtos.SyncMessage.Request r = SignalServiceProtos.SyncMessage.Request.newBuilder().setType(SignalServiceProtos.SyncMessage.Request.Type.GROUPS).build();
+        SignalServiceSyncMessage message = SignalServiceSyncMessage.forRequest(new RequestMessage(r));
+        try {
+            sendSyncMessage(message);
+        } catch (UntrustedIdentityException e) {
+            e.printStackTrace();
+        }
+    }
+
+    private void requestSyncContacts() throws IOException {
+        SignalServiceProtos.SyncMessage.Request r = SignalServiceProtos.SyncMessage.Request.newBuilder().setType(SignalServiceProtos.SyncMessage.Request.Type.CONTACTS).build();
+        SignalServiceSyncMessage message = SignalServiceSyncMessage.forRequest(new RequestMessage(r));
+        try {
+            sendSyncMessage(message);
+        } catch (UntrustedIdentityException e) {
+            e.printStackTrace();
+        }
+    }
+
+    private byte[] getSelfUnidentifiedAccessKey() {
+        return UnidentifiedAccess.deriveAccessKeyFrom(profileKey);
+    }
+
+    private static byte[] getTargetUnidentifiedAccessKey(SignalServiceAddress recipient) {
+        // TODO implement
+        return null;
+    }
+
+    public Optional<UnidentifiedAccessPair> getAccessForSync() {
+        // TODO implement
+        return Optional.absent();
+    }
+
+    public List<Optional<UnidentifiedAccessPair>> getAccessFor(Collection<SignalServiceAddress> recipients) {
+        List<Optional<UnidentifiedAccessPair>> result = new ArrayList<>(recipients.size());
+        for (SignalServiceAddress recipient : recipients) {
+            result.add(Optional.<UnidentifiedAccessPair>absent());
+        }
+        return result;
+    }
+
+    public Optional<UnidentifiedAccessPair> getAccessFor(SignalServiceAddress recipient) {
+        // TODO implement
+        return Optional.absent();
+    }
+
+    private void sendSyncMessage(SignalServiceSyncMessage message)
+            throws IOException, UntrustedIdentityException {
+        SignalServiceMessageSender messageSender = new SignalServiceMessageSender(serviceConfiguration, username, password,
+                deviceId, signalProtocolStore, USER_AGENT, isMultiDevice, Optional.fromNullable(messagePipe), Optional.fromNullable(unidentifiedMessagePipe), Optional.<SignalServiceMessageSender.EventListener>absent());
+        try {
+            messageSender.sendMessage(message, getAccessForSync());
+        } catch (UntrustedIdentityException e) {
+            signalProtocolStore.saveIdentity(e.getE164Number(), e.getIdentityKey(), TrustLevel.UNTRUSTED);
+            throw e;
+        }
+    }
+
+    /**
+     * This method throws an EncapsulatedExceptions exception instead of returning a list of SendMessageResult.
+     */
+    private void sendMessageLegacy(SignalServiceDataMessage.Builder messageBuilder, Collection<String> recipients)
+            throws EncapsulatedExceptions, IOException {
+        List<SendMessageResult> results = sendMessage(messageBuilder, recipients);
+
+        List<UntrustedIdentityException> untrustedIdentities = new LinkedList<>();
+        List<UnregisteredUserException> unregisteredUsers = new LinkedList<>();
+        List<NetworkFailureException> networkExceptions = new LinkedList<>();
+
+        for (SendMessageResult result : results) {
+            if (result.isUnregisteredFailure()) {
+                unregisteredUsers.add(new UnregisteredUserException(result.getAddress().getNumber(), null));
+            } else if (result.isNetworkFailure()) {
+                networkExceptions.add(new NetworkFailureException(result.getAddress().getNumber(), null));
+            } else if (result.getIdentityFailure() != null) {
+                untrustedIdentities.add(new UntrustedIdentityException("Untrusted", result.getAddress().getNumber(), result.getIdentityFailure().getIdentityKey()));
+            }
+        }
+        if (!untrustedIdentities.isEmpty() || !unregisteredUsers.isEmpty() || !networkExceptions.isEmpty()) {
+            throw new EncapsulatedExceptions(untrustedIdentities, unregisteredUsers, networkExceptions);
+        }
+    }
+
+    private List<SendMessageResult> sendMessage(SignalServiceDataMessage.Builder messageBuilder, Collection<String> recipients)
+            throws IOException {
+        Set<SignalServiceAddress> recipientsTS = getSignalServiceAddresses(recipients);
+        if (recipientsTS == null) return Collections.emptyList();
+
+        SignalServiceDataMessage message = null;
+        try {
+            SignalServiceMessageSender messageSender = new SignalServiceMessageSender(serviceConfiguration, username, password,
+                    deviceId, signalProtocolStore, USER_AGENT, isMultiDevice, Optional.fromNullable(messagePipe), Optional.fromNullable(unidentifiedMessagePipe), Optional.<SignalServiceMessageSender.EventListener>absent());
+
+            message = messageBuilder.build();
+            if (message.getGroupInfo().isPresent()) {
+                try {
+                    List<SendMessageResult> result = messageSender.sendMessage(new ArrayList<>(recipientsTS), getAccessFor(recipientsTS), message);
+                    for (SendMessageResult r : result) {
+                        if (r.getIdentityFailure() != null) {
+                            signalProtocolStore.saveIdentity(r.getAddress().getNumber(), r.getIdentityFailure().getIdentityKey(), TrustLevel.UNTRUSTED);
+                        }
+                    }
+                    return result;
+                } catch (UntrustedIdentityException e) {
+                    signalProtocolStore.saveIdentity(e.getE164Number(), e.getIdentityKey(), TrustLevel.UNTRUSTED);
+                    return Collections.emptyList();
+                }
+            } else {
+                // Send to all individually, so sync messages are sent correctly
+                List<SendMessageResult> results = new ArrayList<>(recipientsTS.size());
+                for (SignalServiceAddress address : recipientsTS) {
+                    ThreadInfo thread = threadStore.getThread(address.getNumber());
+                    if (thread != null) {
+                        messageBuilder.withExpiration(thread.messageExpirationTime);
+                    } else {
+                        messageBuilder.withExpiration(0);
+                    }
+                    message = messageBuilder.build();
+                    try {
+                        SendMessageResult result = messageSender.sendMessage(address, getAccessFor(address), message);
+                        results.add(result);
+                    } catch (UntrustedIdentityException e) {
+                        signalProtocolStore.saveIdentity(e.getE164Number(), e.getIdentityKey(), TrustLevel.UNTRUSTED);
+                        results.add(SendMessageResult.identityFailure(address, e.getIdentityKey()));
+                    }
+                }
+                return results;
+            }
+        } finally {
+            if (message != null && message.isEndSession()) {
+                for (SignalServiceAddress recipient : recipientsTS) {
+                    handleEndSession(recipient.getNumber());
+                }
+            }
+            save();
+        }
+    }
 
+    private Set<SignalServiceAddress> getSignalServiceAddresses(Collection<String> recipients) {
         Set<SignalServiceAddress> recipientsTS = new HashSet<>(recipients.size());
         for (String recipient : recipients) {
             try {
@@ -422,35 +1044,29 @@ class Manager implements Signal {
                 System.err.println("Failed to add recipient \"" + recipient + "\": " + e.getMessage());
                 System.err.println("Aborting sending.");
                 save();
-                return;
-            }
-        }
-
-        if (message.getGroupInfo().isPresent()) {
-            messageSender.sendMessage(new ArrayList<>(recipientsTS), message);
-        } else {
-            // Send to all individually, so sync messages are sent correctly
-            for (SignalServiceAddress address : recipientsTS) {
-                messageSender.sendMessage(address, message);
+                return null;
             }
         }
+        return recipientsTS;
+    }
 
-        if (message.isEndSession()) {
-            for (SignalServiceAddress recipient : recipientsTS) {
-                handleEndSession(recipient.getNumber());
-            }
+    public static CertificateValidator getCertificateValidator() {
+        try {
+            ECPublicKey unidentifiedSenderTrustRoot = Curve.decodePoint(Base64.decode(UNIDENTIFIED_SENDER_TRUST_ROOT), 0);
+            return new CertificateValidator(unidentifiedSenderTrustRoot);
+        } catch (InvalidKeyException | IOException e) {
+            throw new AssertionError(e);
         }
-        save();
     }
 
-    private SignalServiceContent decryptMessage(SignalServiceEnvelope envelope) {
-        SignalServiceCipher cipher = new SignalServiceCipher(new SignalServiceAddress(username), signalProtocolStore);
+    private SignalServiceContent decryptMessage(SignalServiceEnvelope envelope) throws org.whispersystems.libsignal.UntrustedIdentityException, InvalidMetadataMessageException, ProtocolInvalidMessageException, ProtocolDuplicateMessageException, ProtocolLegacyMessageException, ProtocolInvalidKeyIdException, InvalidMetadataVersionException, ProtocolInvalidVersionException, ProtocolNoSessionException, ProtocolInvalidKeyException, ProtocolUntrustedIdentityException, SelfSendException {
+        SignalServiceCipher cipher = new SignalServiceCipher(new SignalServiceAddress(username), signalProtocolStore, getCertificateValidator());
         try {
             return cipher.decrypt(envelope);
-        } catch (Exception e) {
-            // TODO handle all exceptions
-            e.printStackTrace();
-            return null;
+        } catch (ProtocolUntrustedIdentityException e) {
+            // TODO We don't get the new untrusted identity from ProtocolUntrustedIdentityException anymore ... we need to get it from somewhere else
+//            signalProtocolStore.saveIdentity(e.getSender(), e.getUntrustedIdentity(), TrustLevel.UNTRUSTED);
+            throw e;
         }
     }
 
@@ -459,30 +1075,28 @@ class Manager implements Signal {
     }
 
     public interface ReceiveMessageHandler {
-        void handleMessage(SignalServiceEnvelope envelope, SignalServiceContent decryptedContent, GroupInfo group);
+        void handleMessage(SignalServiceEnvelope envelope, SignalServiceContent decryptedContent, Throwable e);
     }
 
-    private GroupInfo handleSignalServiceDataMessage(SignalServiceDataMessage message, boolean isSync, String source, String destination) {
-        GroupInfo group = null;
+    private void handleSignalServiceDataMessage(SignalServiceDataMessage message, boolean isSync, String source, String destination, boolean ignoreAttachments) {
+        String threadId;
         if (message.getGroupInfo().isPresent()) {
             SignalServiceGroup groupInfo = message.getGroupInfo().get();
+            threadId = Base64.encodeBytes(groupInfo.getGroupId());
+            GroupInfo group = groupStore.getGroup(groupInfo.getGroupId());
             switch (groupInfo.getType()) {
                 case UPDATE:
-                    try {
-                        group = groupStore.getGroup(groupInfo.getGroupId());
-                    } catch (GroupNotFoundException e) {
+                    if (group == null) {
                         group = new GroupInfo(groupInfo.getGroupId());
                     }
 
                     if (groupInfo.getAvatar().isPresent()) {
                         SignalServiceAttachment avatar = groupInfo.getAvatar().get();
                         if (avatar.isPointer()) {
-                            long avatarId = avatar.asPointer().getId();
                             try {
-                                retrieveAttachment(avatar.asPointer());
-                                group.avatarId = avatarId;
+                                retrieveGroupAvatarAttachment(avatar.asPointer(), group.groupId);
                             } catch (IOException | InvalidMessageException e) {
-                                System.err.println("Failed to retrieve group avatar (" + avatarId + "): " + e.getMessage());
+                                System.err.println("Failed to retrieve group avatar (" + avatar.asPointer().getId() + "): " + e.getMessage());
                             }
                         }
                     }
@@ -498,24 +1112,60 @@ class Manager implements Signal {
                     groupStore.updateGroup(group);
                     break;
                 case DELIVER:
-                    try {
-                        group = groupStore.getGroup(groupInfo.getGroupId());
-                    } catch (GroupNotFoundException e) {
+                    if (group == null) {
+                        try {
+                            sendGroupInfoRequest(groupInfo.getGroupId(), source);
+                        } catch (IOException | EncapsulatedExceptions e) {
+                            e.printStackTrace();
+                        }
                     }
                     break;
                 case QUIT:
-                    try {
-                        group = groupStore.getGroup(groupInfo.getGroupId());
+                    if (group == null) {
+                        try {
+                            sendGroupInfoRequest(groupInfo.getGroupId(), source);
+                        } catch (IOException | EncapsulatedExceptions e) {
+                            e.printStackTrace();
+                        }
+                    } else {
                         group.members.remove(source);
-                    } catch (GroupNotFoundException e) {
+                        groupStore.updateGroup(group);
+                    }
+                    break;
+                case REQUEST_INFO:
+                    if (group != null) {
+                        try {
+                            sendUpdateGroupMessage(groupInfo.getGroupId(), source);
+                        } catch (IOException | EncapsulatedExceptions e) {
+                            e.printStackTrace();
+                        } catch (NotAGroupMemberException e) {
+                            // We have left this group, so don't send a group update message
+                        }
                     }
                     break;
             }
+        } else {
+            if (isSync) {
+                threadId = destination;
+            } else {
+                threadId = source;
+            }
         }
         if (message.isEndSession()) {
             handleEndSession(isSync ? destination : source);
         }
-        if (message.getAttachments().isPresent()) {
+        if (message.isExpirationUpdate() || message.getBody().isPresent()) {
+            ThreadInfo thread = threadStore.getThread(threadId);
+            if (thread == null) {
+                thread = new ThreadInfo();
+                thread.id = threadId;
+            }
+            if (thread.messageExpirationTime != message.getExpiresInSeconds()) {
+                thread.messageExpirationTime = message.getExpiresInSeconds();
+                threadStore.updateThread(thread);
+            }
+        }
+        if (message.getAttachments().isPresent() && !ignoreAttachments) {
             for (SignalServiceAttachment attachment : message.getAttachments().get()) {
                 if (attachment.isPointer()) {
                     try {
@@ -526,56 +1176,358 @@ class Manager implements Signal {
                 }
             }
         }
-        return group;
+        if (message.getProfileKey().isPresent() && message.getProfileKey().get().length == 32) {
+            ContactInfo contact = contactStore.getContact(source);
+            if (contact == null) {
+                contact = new ContactInfo();
+                contact.number = source;
+            }
+            contact.profileKey = Base64.encodeBytes(message.getProfileKey().get());
+        }
     }
 
-    public void receiveMessages(int timeoutSeconds, boolean returnOnTimeout, ReceiveMessageHandler handler) throws IOException {
-        final SignalServiceMessageReceiver messageReceiver = new SignalServiceMessageReceiver(URL, TRUST_STORE, username, password, signalingKey, USER_AGENT);
-        SignalServiceMessagePipe messagePipe = null;
+    public void retryFailedReceivedMessages(ReceiveMessageHandler handler, boolean ignoreAttachments) {
+        final File cachePath = new File(getMessageCachePath());
+        if (!cachePath.exists()) {
+            return;
+        }
+        for (final File dir : cachePath.listFiles()) {
+            if (!dir.isDirectory()) {
+                continue;
+            }
+
+            for (final File fileEntry : dir.listFiles()) {
+                if (!fileEntry.isFile()) {
+                    continue;
+                }
+                SignalServiceEnvelope envelope;
+                try {
+                    envelope = loadEnvelope(fileEntry);
+                    if (envelope == null) {
+                        continue;
+                    }
+                } catch (IOException e) {
+                    e.printStackTrace();
+                    continue;
+                }
+                SignalServiceContent content = null;
+                if (!envelope.isReceipt()) {
+                    try {
+                        content = decryptMessage(envelope);
+                    } catch (Exception e) {
+                        continue;
+                    }
+                    handleMessage(envelope, content, ignoreAttachments);
+                }
+                save();
+                handler.handleMessage(envelope, content, null);
+                try {
+                    Files.delete(fileEntry.toPath());
+                } catch (IOException e) {
+                    System.err.println("Failed to delete cached message file “" + fileEntry + "”: " + e.getMessage());
+                }
+            }
+            // Try to delete directory if empty
+            dir.delete();
+        }
+    }
+
+    public void receiveMessages(long timeout, TimeUnit unit, boolean returnOnTimeout, boolean ignoreAttachments, ReceiveMessageHandler handler) throws IOException {
+        retryFailedReceivedMessages(handler, ignoreAttachments);
+        final SignalServiceMessageReceiver messageReceiver = new SignalServiceMessageReceiver(serviceConfiguration, username, password, deviceId, signalingKey, USER_AGENT, null, timer);
 
         try {
-            messagePipe = messageReceiver.createMessagePipe();
+            if (messagePipe == null) {
+                messagePipe = messageReceiver.createMessagePipe();
+            }
 
             while (true) {
                 SignalServiceEnvelope envelope;
                 SignalServiceContent content = null;
-                GroupInfo group = null;
+                Exception exception = null;
+                final long now = new Date().getTime();
                 try {
-                    envelope = messagePipe.read(timeoutSeconds, TimeUnit.SECONDS);
-                    if (!envelope.isReceipt()) {
-                        content = decryptMessage(envelope);
-                        if (content != null) {
-                            if (content.getDataMessage().isPresent()) {
-                                SignalServiceDataMessage message = content.getDataMessage().get();
-                                group = handleSignalServiceDataMessage(message, false, envelope.getSource(), username);
-                            }
-                            if (content.getSyncMessage().isPresent()) {
-                                SignalServiceSyncMessage syncMessage = content.getSyncMessage().get();
-                                if (syncMessage.getSent().isPresent()) {
-                                    SignalServiceDataMessage message = syncMessage.getSent().get().getMessage();
-                                    group = handleSignalServiceDataMessage(message, true, envelope.getSource(), syncMessage.getSent().get().getDestination().get());
-                                }
-                                if (syncMessage.getRequest().isPresent()) {
-                                    // TODO
-                                }
-                                if (syncMessage.getGroups().isPresent()) {
-                                    // TODO
-                                }
+                    envelope = messagePipe.read(timeout, unit, new SignalServiceMessagePipe.MessagePipeCallback() {
+                        @Override
+                        public void onMessage(SignalServiceEnvelope envelope) {
+                            // store message on disk, before acknowledging receipt to the server
+                            try {
+                                File cacheFile = getMessageCacheFile(envelope.getSource(), now, envelope.getTimestamp());
+                                storeEnvelope(envelope, cacheFile);
+                            } catch (IOException e) {
+                                System.err.println("Failed to store encrypted message in disk cache, ignoring: " + e.getMessage());
                             }
                         }
-                    }
-                    save();
-                    handler.handleMessage(envelope, content, group);
+                    });
                 } catch (TimeoutException e) {
                     if (returnOnTimeout)
                         return;
+                    continue;
                 } catch (InvalidVersionException e) {
                     System.err.println("Ignoring error: " + e.getMessage());
+                    continue;
+                }
+                if (!envelope.isReceipt()) {
+                    try {
+                        content = decryptMessage(envelope);
+                    } catch (Exception e) {
+                        exception = e;
+                    }
+                    handleMessage(envelope, content, ignoreAttachments);
+                }
+                save();
+                handler.handleMessage(envelope, content, exception);
+                if (exception == null || !(exception instanceof org.whispersystems.libsignal.UntrustedIdentityException)) {
+                    File cacheFile = null;
+                    try {
+                        cacheFile = getMessageCacheFile(envelope.getSource(), now, envelope.getTimestamp());
+                        Files.delete(cacheFile.toPath());
+                        // Try to delete directory if empty
+                        new File(getMessageCachePath()).delete();
+                    } catch (IOException e) {
+                        System.err.println("Failed to delete cached message file “" + cacheFile + "”: " + e.getMessage());
+                    }
                 }
             }
         } finally {
-            if (messagePipe != null)
+            if (messagePipe != null) {
                 messagePipe.shutdown();
+                messagePipe = null;
+            }
+        }
+    }
+
+    private void handleMessage(SignalServiceEnvelope envelope, SignalServiceContent content, boolean ignoreAttachments) {
+        if (content != null) {
+            if (content.getDataMessage().isPresent()) {
+                SignalServiceDataMessage message = content.getDataMessage().get();
+                handleSignalServiceDataMessage(message, false, envelope.getSource(), username, ignoreAttachments);
+            }
+            if (content.getSyncMessage().isPresent()) {
+                isMultiDevice = true;
+                SignalServiceSyncMessage syncMessage = content.getSyncMessage().get();
+                if (syncMessage.getSent().isPresent()) {
+                    SignalServiceDataMessage message = syncMessage.getSent().get().getMessage();
+                    handleSignalServiceDataMessage(message, true, envelope.getSource(), syncMessage.getSent().get().getDestination().get(), ignoreAttachments);
+                }
+                if (syncMessage.getRequest().isPresent()) {
+                    RequestMessage rm = syncMessage.getRequest().get();
+                    if (rm.isContactsRequest()) {
+                        try {
+                            sendContacts();
+                        } catch (UntrustedIdentityException | IOException e) {
+                            e.printStackTrace();
+                        }
+                    }
+                    if (rm.isGroupsRequest()) {
+                        try {
+                            sendGroups();
+                        } catch (UntrustedIdentityException | IOException e) {
+                            e.printStackTrace();
+                        }
+                    }
+                }
+                if (syncMessage.getGroups().isPresent()) {
+                    File tmpFile = null;
+                    try {
+                        tmpFile = Util.createTempFile();
+                        try (InputStream attachmentAsStream = retrieveAttachmentAsStream(syncMessage.getGroups().get().asPointer(), tmpFile)) {
+                            DeviceGroupsInputStream s = new DeviceGroupsInputStream(attachmentAsStream);
+                            DeviceGroup g;
+                            while ((g = s.read()) != null) {
+                                GroupInfo syncGroup = groupStore.getGroup(g.getId());
+                                if (syncGroup == null) {
+                                    syncGroup = new GroupInfo(g.getId());
+                                }
+                                if (g.getName().isPresent()) {
+                                    syncGroup.name = g.getName().get();
+                                }
+                                syncGroup.members.addAll(g.getMembers());
+                                syncGroup.active = g.isActive();
+                                if (g.getColor().isPresent()) {
+                                    syncGroup.color = g.getColor().get();
+                                }
+
+                                if (g.getAvatar().isPresent()) {
+                                    retrieveGroupAvatarAttachment(g.getAvatar().get(), syncGroup.groupId);
+                                }
+                                groupStore.updateGroup(syncGroup);
+                            }
+                        }
+                    } catch (Exception e) {
+                        e.printStackTrace();
+                    } finally {
+                        if (tmpFile != null) {
+                            try {
+                                Files.delete(tmpFile.toPath());
+                            } catch (IOException e) {
+                                System.err.println("Failed to delete received groups temp file “" + tmpFile + "”: " + e.getMessage());
+                            }
+                        }
+                    }
+                    if (syncMessage.getBlockedList().isPresent()) {
+                        // TODO store list of blocked numbers
+                    }
+                }
+                if (syncMessage.getContacts().isPresent()) {
+                    File tmpFile = null;
+                    try {
+                        tmpFile = Util.createTempFile();
+                        final ContactsMessage contactsMessage = syncMessage.getContacts().get();
+                        try (InputStream attachmentAsStream = retrieveAttachmentAsStream(contactsMessage.getContactsStream().asPointer(), tmpFile)) {
+                            DeviceContactsInputStream s = new DeviceContactsInputStream(attachmentAsStream);
+                            if (contactsMessage.isComplete()) {
+                                contactStore.clear();
+                            }
+                            DeviceContact c;
+                            while ((c = s.read()) != null) {
+                                ContactInfo contact = contactStore.getContact(c.getNumber());
+                                if (contact == null) {
+                                    contact = new ContactInfo();
+                                    contact.number = c.getNumber();
+                                }
+                                if (c.getName().isPresent()) {
+                                    contact.name = c.getName().get();
+                                }
+                                if (c.getColor().isPresent()) {
+                                    contact.color = c.getColor().get();
+                                }
+                                if (c.getProfileKey().isPresent()) {
+                                    contact.profileKey = Base64.encodeBytes(c.getProfileKey().get());
+                                }
+                                if (c.getVerified().isPresent()) {
+                                    final VerifiedMessage verifiedMessage = c.getVerified().get();
+                                    signalProtocolStore.saveIdentity(verifiedMessage.getDestination(), verifiedMessage.getIdentityKey(), TrustLevel.fromVerifiedState(verifiedMessage.getVerified()));
+                                }
+                                if (c.getExpirationTimer().isPresent()) {
+                                    ThreadInfo thread = threadStore.getThread(c.getNumber());
+                                    thread.messageExpirationTime = c.getExpirationTimer().get();
+                                    threadStore.updateThread(thread);
+                                }
+                                if (c.isBlocked()) {
+                                    // TODO store list of blocked numbers
+                                }
+                                contactStore.updateContact(contact);
+
+                                if (c.getAvatar().isPresent()) {
+                                    retrieveContactAvatarAttachment(c.getAvatar().get(), contact.number);
+                                }
+                            }
+                        }
+                    } catch (Exception e) {
+                        e.printStackTrace();
+                    } finally {
+                        if (tmpFile != null) {
+                            try {
+                                Files.delete(tmpFile.toPath());
+                            } catch (IOException e) {
+                                System.err.println("Failed to delete received contacts temp file “" + tmpFile + "”: " + e.getMessage());
+                            }
+                        }
+                    }
+                }
+                if (syncMessage.getVerified().isPresent()) {
+                    final VerifiedMessage verifiedMessage = syncMessage.getVerified().get();
+                    signalProtocolStore.saveIdentity(verifiedMessage.getDestination(), verifiedMessage.getIdentityKey(), TrustLevel.fromVerifiedState(verifiedMessage.getVerified()));
+                }
+            }
+        }
+    }
+
+    private SignalServiceEnvelope loadEnvelope(File file) throws IOException {
+        try (FileInputStream f = new FileInputStream(file)) {
+            DataInputStream in = new DataInputStream(f);
+            int version = in.readInt();
+            if (version > 2) {
+                return null;
+            }
+            int type = in.readInt();
+            String source = in.readUTF();
+            int sourceDevice = in.readInt();
+            if (version == 1) {
+                // read legacy relay field
+                in.readUTF();
+            }
+            long timestamp = in.readLong();
+            byte[] content = null;
+            int contentLen = in.readInt();
+            if (contentLen > 0) {
+                content = new byte[contentLen];
+                in.readFully(content);
+            }
+            byte[] legacyMessage = null;
+            int legacyMessageLen = in.readInt();
+            if (legacyMessageLen > 0) {
+                legacyMessage = new byte[legacyMessageLen];
+                in.readFully(legacyMessage);
+            }
+            long serverTimestamp = 0;
+            String uuid = null;
+            if (version == 2) {
+                serverTimestamp = in.readLong();
+                uuid = in.readUTF();
+                if ("".equals(uuid)) {
+                    uuid = null;
+                }
+            }
+            return new SignalServiceEnvelope(type, source, sourceDevice, timestamp, legacyMessage, content, serverTimestamp, uuid);
+        }
+    }
+
+    private void storeEnvelope(SignalServiceEnvelope envelope, File file) throws IOException {
+        try (FileOutputStream f = new FileOutputStream(file)) {
+            try (DataOutputStream out = new DataOutputStream(f)) {
+                out.writeInt(2); // version
+                out.writeInt(envelope.getType());
+                out.writeUTF(envelope.getSource());
+                out.writeInt(envelope.getSourceDevice());
+                out.writeLong(envelope.getTimestamp());
+                if (envelope.hasContent()) {
+                    out.writeInt(envelope.getContent().length);
+                    out.write(envelope.getContent());
+                } else {
+                    out.writeInt(0);
+                }
+                if (envelope.hasLegacyMessage()) {
+                    out.writeInt(envelope.getLegacyMessage().length);
+                    out.write(envelope.getLegacyMessage());
+                } else {
+                    out.writeInt(0);
+                }
+                out.writeLong(envelope.getServerTimestamp());
+                String uuid = envelope.getUuid();
+                out.writeUTF(uuid == null ? "" : uuid);
+            }
+        }
+    }
+
+    public File getContactAvatarFile(String number) {
+        return new File(avatarsPath, "contact-" + number);
+    }
+
+    private File retrieveContactAvatarAttachment(SignalServiceAttachment attachment, String number) throws IOException, InvalidMessageException {
+        createPrivateDirectories(avatarsPath);
+        if (attachment.isPointer()) {
+            SignalServiceAttachmentPointer pointer = attachment.asPointer();
+            return retrieveAttachment(pointer, getContactAvatarFile(number), false);
+        } else {
+            SignalServiceAttachmentStream stream = attachment.asStream();
+            return retrieveAttachment(stream, getContactAvatarFile(number));
+        }
+    }
+
+    public File getGroupAvatarFile(byte[] groupId) {
+        return new File(avatarsPath, "group-" + Base64.encodeBytes(groupId).replace("/", "_"));
+    }
+
+    private File retrieveGroupAvatarAttachment(SignalServiceAttachment attachment, byte[] groupId) throws IOException, InvalidMessageException {
+        createPrivateDirectories(avatarsPath);
+        if (attachment.isPointer()) {
+            SignalServiceAttachmentPointer pointer = attachment.asPointer();
+            return retrieveAttachment(pointer, getGroupAvatarFile(groupId), false);
+        } else {
+            SignalServiceAttachmentStream stream = attachment.asStream();
+            return retrieveAttachment(stream, getGroupAvatarFile(groupId));
         }
     }
 
@@ -584,16 +1536,14 @@ class Manager implements Signal {
     }
 
     private File retrieveAttachment(SignalServiceAttachmentPointer pointer) throws IOException, InvalidMessageException {
-        final SignalServiceMessageReceiver messageReceiver = new SignalServiceMessageReceiver(URL, TRUST_STORE, username, password, signalingKey, USER_AGENT);
+        createPrivateDirectories(attachmentsPath);
+        return retrieveAttachment(pointer, getAttachmentFile(pointer.getId()), true);
+    }
 
-        File tmpFile = File.createTempFile("ts_attach_" + pointer.getId(), ".tmp");
-        InputStream input = messageReceiver.retrieveAttachment(pointer, tmpFile);
+    private File retrieveAttachment(SignalServiceAttachmentStream stream, File outputFile) throws IOException, InvalidMessageException {
+        InputStream input = stream.getInputStream();
 
-        new File(attachmentsPath).mkdirs();
-        File outputFile = getAttachmentFile(pointer.getId());
-        OutputStream output = null;
-        try {
-            output = new FileOutputStream(outputFile);
+        try (OutputStream output = new FileOutputStream(outputFile)) {
             byte[] buffer = new byte[4096];
             int read;
 
@@ -603,33 +1553,52 @@ class Manager implements Signal {
         } catch (FileNotFoundException e) {
             e.printStackTrace();
             return null;
-        } finally {
-            if (output != null) {
-                output.close();
-                output = null;
-            }
-            if (!tmpFile.delete()) {
-                System.err.println("Failed to delete temp file: " + tmpFile);
-            }
         }
-        if (pointer.getPreview().isPresent()) {
+        return outputFile;
+    }
+
+    private File retrieveAttachment(SignalServiceAttachmentPointer pointer, File outputFile, boolean storePreview) throws IOException, InvalidMessageException {
+        if (storePreview && pointer.getPreview().isPresent()) {
             File previewFile = new File(outputFile + ".preview");
-            try {
-                output = new FileOutputStream(previewFile);
+            try (OutputStream output = new FileOutputStream(previewFile)) {
                 byte[] preview = pointer.getPreview().get();
                 output.write(preview, 0, preview.length);
             } catch (FileNotFoundException e) {
                 e.printStackTrace();
                 return null;
-            } finally {
-                if (output != null) {
-                    output.close();
+            }
+        }
+
+        final SignalServiceMessageReceiver messageReceiver = new SignalServiceMessageReceiver(serviceConfiguration, username, password, deviceId, signalingKey, USER_AGENT, null, timer);
+
+        File tmpFile = Util.createTempFile();
+        try (InputStream input = messageReceiver.retrieveAttachment(pointer, tmpFile, MAX_ATTACHMENT_SIZE)) {
+            try (OutputStream output = new FileOutputStream(outputFile)) {
+                byte[] buffer = new byte[4096];
+                int read;
+
+                while ((read = input.read(buffer)) != -1) {
+                    output.write(buffer, 0, read);
                 }
+            } catch (FileNotFoundException e) {
+                e.printStackTrace();
+                return null;
+            }
+        } finally {
+            try {
+                Files.delete(tmpFile.toPath());
+            } catch (IOException e) {
+                System.err.println("Failed to delete received attachment temp file “" + tmpFile + "”: " + e.getMessage());
             }
         }
         return outputFile;
     }
 
+    private InputStream retrieveAttachmentAsStream(SignalServiceAttachmentPointer pointer, File tmpFile) throws IOException, InvalidMessageException {
+        final SignalServiceMessageReceiver messageReceiver = new SignalServiceMessageReceiver(serviceConfiguration, username, password, deviceId, signalingKey, USER_AGENT, null, timer);
+        return messageReceiver.retrieveAttachment(pointer, tmpFile, MAX_ATTACHMENT_SIZE);
+    }
+
     private String canonicalizeNumber(String number) throws InvalidNumberException {
         String localNumber = username;
         return PhoneNumberFormatter.formatNumber(number, localNumber);
@@ -644,4 +1613,195 @@ class Manager implements Signal {
     public boolean isRemote() {
         return false;
     }
+
+    private void sendGroups() throws IOException, UntrustedIdentityException {
+        File groupsFile = Util.createTempFile();
+
+        try {
+            try (OutputStream fos = new FileOutputStream(groupsFile)) {
+                DeviceGroupsOutputStream out = new DeviceGroupsOutputStream(fos);
+                for (GroupInfo record : groupStore.getGroups()) {
+                    ThreadInfo info = threadStore.getThread(Base64.encodeBytes(record.groupId));
+                    out.write(new DeviceGroup(record.groupId, Optional.fromNullable(record.name),
+                            new ArrayList<>(record.members), createGroupAvatarAttachment(record.groupId),
+                            record.active, Optional.fromNullable(info != null ? info.messageExpirationTime : null),
+                            Optional.fromNullable(record.color), false));
+                }
+            }
+
+            if (groupsFile.exists() && groupsFile.length() > 0) {
+                try (FileInputStream groupsFileStream = new FileInputStream(groupsFile)) {
+                    SignalServiceAttachmentStream attachmentStream = SignalServiceAttachment.newStreamBuilder()
+                            .withStream(groupsFileStream)
+                            .withContentType("application/octet-stream")
+                            .withLength(groupsFile.length())
+                            .build();
+
+                    sendSyncMessage(SignalServiceSyncMessage.forGroups(attachmentStream));
+                }
+            }
+        } finally {
+            try {
+                Files.delete(groupsFile.toPath());
+            } catch (IOException e) {
+                System.err.println("Failed to delete groups temp file “" + groupsFile + "”: " + e.getMessage());
+            }
+        }
+    }
+
+    private void sendContacts() throws IOException, UntrustedIdentityException {
+        File contactsFile = Util.createTempFile();
+
+        try {
+            try (OutputStream fos = new FileOutputStream(contactsFile)) {
+                DeviceContactsOutputStream out = new DeviceContactsOutputStream(fos);
+                for (ContactInfo record : contactStore.getContacts()) {
+                    VerifiedMessage verifiedMessage = null;
+                    ThreadInfo info = threadStore.getThread(record.number);
+                    if (getIdentities().containsKey(record.number)) {
+                        JsonIdentityKeyStore.Identity currentIdentity = null;
+                        for (JsonIdentityKeyStore.Identity id : getIdentities().get(record.number)) {
+                            if (currentIdentity == null || id.getDateAdded().after(currentIdentity.getDateAdded())) {
+                                currentIdentity = id;
+                            }
+                        }
+                        if (currentIdentity != null) {
+                            verifiedMessage = new VerifiedMessage(record.number, currentIdentity.getIdentityKey(), currentIdentity.getTrustLevel().toVerifiedState(), currentIdentity.getDateAdded().getTime());
+                        }
+                    }
+
+                    byte[] profileKey = record.profileKey == null ? null : Base64.decode(record.profileKey);
+                    // TODO store list of blocked numbers
+                    boolean blocked = false;
+                    out.write(new DeviceContact(record.number, Optional.fromNullable(record.name),
+                            createContactAvatarAttachment(record.number), Optional.fromNullable(record.color),
+                            Optional.fromNullable(verifiedMessage), Optional.fromNullable(profileKey), blocked, Optional.fromNullable(info != null ? info.messageExpirationTime : null)));
+                }
+            }
+
+            if (contactsFile.exists() && contactsFile.length() > 0) {
+                try (FileInputStream contactsFileStream = new FileInputStream(contactsFile)) {
+                    SignalServiceAttachmentStream attachmentStream = SignalServiceAttachment.newStreamBuilder()
+                            .withStream(contactsFileStream)
+                            .withContentType("application/octet-stream")
+                            .withLength(contactsFile.length())
+                            .build();
+
+                    sendSyncMessage(SignalServiceSyncMessage.forContacts(new ContactsMessage(attachmentStream, true)));
+                }
+            }
+        } finally {
+            try {
+                Files.delete(contactsFile.toPath());
+            } catch (IOException e) {
+                System.err.println("Failed to delete contacts temp file “" + contactsFile + "”: " + e.getMessage());
+            }
+        }
+    }
+
+    private void sendVerifiedMessage(String destination, IdentityKey identityKey, TrustLevel trustLevel) throws IOException, UntrustedIdentityException {
+        VerifiedMessage verifiedMessage = new VerifiedMessage(destination, identityKey, trustLevel.toVerifiedState(), System.currentTimeMillis());
+        sendSyncMessage(SignalServiceSyncMessage.forVerified(verifiedMessage));
+    }
+
+    public ContactInfo getContact(String number) {
+        return contactStore.getContact(number);
+    }
+
+    public GroupInfo getGroup(byte[] groupId) {
+        return groupStore.getGroup(groupId);
+    }
+
+    public Map<String, List<JsonIdentityKeyStore.Identity>> getIdentities() {
+        return signalProtocolStore.getIdentities();
+    }
+
+    public List<JsonIdentityKeyStore.Identity> getIdentities(String number) {
+        return signalProtocolStore.getIdentities(number);
+    }
+
+    /**
+     * Trust this the identity with this fingerprint
+     *
+     * @param name        username of the identity
+     * @param fingerprint Fingerprint
+     */
+    public boolean trustIdentityVerified(String name, byte[] fingerprint) {
+        List<JsonIdentityKeyStore.Identity> ids = signalProtocolStore.getIdentities(name);
+        if (ids == null) {
+            return false;
+        }
+        for (JsonIdentityKeyStore.Identity id : ids) {
+            if (!Arrays.equals(id.getIdentityKey().serialize(), fingerprint)) {
+                continue;
+            }
+
+            signalProtocolStore.saveIdentity(name, id.getIdentityKey(), TrustLevel.TRUSTED_VERIFIED);
+            try {
+                sendVerifiedMessage(name, id.getIdentityKey(), TrustLevel.TRUSTED_VERIFIED);
+            } catch (IOException | UntrustedIdentityException e) {
+                e.printStackTrace();
+            }
+            save();
+            return true;
+        }
+        return false;
+    }
+
+    /**
+     * Trust this the identity with this safety number
+     *
+     * @param name         username of the identity
+     * @param safetyNumber Safety number
+     */
+    public boolean trustIdentityVerifiedSafetyNumber(String name, String safetyNumber) {
+        List<JsonIdentityKeyStore.Identity> ids = signalProtocolStore.getIdentities(name);
+        if (ids == null) {
+            return false;
+        }
+        for (JsonIdentityKeyStore.Identity id : ids) {
+            if (!safetyNumber.equals(computeSafetyNumber(name, id.getIdentityKey()))) {
+                continue;
+            }
+
+            signalProtocolStore.saveIdentity(name, id.getIdentityKey(), TrustLevel.TRUSTED_VERIFIED);
+            try {
+                sendVerifiedMessage(name, id.getIdentityKey(), TrustLevel.TRUSTED_VERIFIED);
+            } catch (IOException | UntrustedIdentityException e) {
+                e.printStackTrace();
+            }
+            save();
+            return true;
+        }
+        return false;
+    }
+
+    /**
+     * Trust all keys of this identity without verification
+     *
+     * @param name username of the identity
+     */
+    public boolean trustIdentityAllKeys(String name) {
+        List<JsonIdentityKeyStore.Identity> ids = signalProtocolStore.getIdentities(name);
+        if (ids == null) {
+            return false;
+        }
+        for (JsonIdentityKeyStore.Identity id : ids) {
+            if (id.getTrustLevel() == TrustLevel.UNTRUSTED) {
+                signalProtocolStore.saveIdentity(name, id.getIdentityKey(), TrustLevel.TRUSTED_UNVERIFIED);
+                try {
+                    sendVerifiedMessage(name, id.getIdentityKey(), TrustLevel.TRUSTED_UNVERIFIED);
+                } catch (IOException | UntrustedIdentityException e) {
+                    e.printStackTrace();
+                }
+            }
+        }
+        save();
+        return true;
+    }
+
+    public String computeSafetyNumber(String theirUsername, IdentityKey theirIdentityKey) {
+        Fingerprint fingerprint = new NumericFingerprintGenerator(5200).createFor(username, getIdentity(), theirUsername, theirIdentityKey);
+        return fingerprint.getDisplayableFingerprint().getDisplayText();
+    }
 }