nmode's Git Repositories - signal-cli/blob - lib/src/main/java/org/asamk/signal/manager/helper/GroupV2Helper.java

   1 package org.asamk.signal.manager.helper;
   2
   3 import com.google.protobuf.InvalidProtocolBufferException;
   4
   5 import org.asamk.signal.manager.groups.GroupLinkPassword;
   6 import org.asamk.signal.manager.groups.GroupLinkState;
   7 import org.asamk.signal.manager.groups.GroupPermission;
   8 import org.asamk.signal.manager.groups.GroupUtils;
   9 import org.asamk.signal.manager.storage.groups.GroupInfoV2;
  10 import org.asamk.signal.manager.storage.recipients.Profile;
  11 import org.asamk.signal.manager.storage.recipients.RecipientId;
  12 import org.asamk.signal.manager.util.IOUtils;
  13 import org.signal.storageservice.protos.groups.AccessControl;
  14 import org.signal.storageservice.protos.groups.GroupChange;
  15 import org.signal.storageservice.protos.groups.Member;
  16 import org.signal.storageservice.protos.groups.local.DecryptedGroup;
  17 import org.signal.storageservice.protos.groups.local.DecryptedGroupChange;
  18 import org.signal.storageservice.protos.groups.local.DecryptedGroupJoinInfo;
  19 import org.signal.storageservice.protos.groups.local.DecryptedPendingMember;
  20 import org.signal.zkgroup.InvalidInputException;
  21 import org.signal.zkgroup.VerificationFailedException;
  22 import org.signal.zkgroup.groups.GroupMasterKey;
  23 import org.signal.zkgroup.groups.GroupSecretParams;
  24 import org.signal.zkgroup.groups.UuidCiphertext;
  25 import org.slf4j.Logger;
  26 import org.slf4j.LoggerFactory;
  27 import org.whispersystems.libsignal.util.Pair;
  28 import org.whispersystems.libsignal.util.guava.Optional;
  29 import org.whispersystems.signalservice.api.groupsv2.DecryptedGroupUtil;
  30 import org.whispersystems.signalservice.api.groupsv2.GroupCandidate;
  31 import org.whispersystems.signalservice.api.groupsv2.GroupLinkNotActiveException;
  32 import org.whispersystems.signalservice.api.groupsv2.GroupsV2Api;
  33 import org.whispersystems.signalservice.api.groupsv2.GroupsV2AuthorizationString;
  34 import org.whispersystems.signalservice.api.groupsv2.GroupsV2Operations;
  35 import org.whispersystems.signalservice.api.groupsv2.InvalidGroupStateException;
  36 import org.whispersystems.signalservice.api.groupsv2.NotAbleToApplyGroupV2ChangeException;
  37 import org.whispersystems.signalservice.api.push.SignalServiceAddress;
  38 import org.whispersystems.signalservice.api.util.UuidUtil;
  39
  40 import java.io.File;
  41 import java.io.FileInputStream;
  42 import java.io.IOException;
  43 import java.io.InputStream;
  44 import java.util.Set;
  45 import java.util.UUID;
  46 import java.util.concurrent.TimeUnit;
  47 import java.util.stream.Collectors;
  48
  49 public class GroupV2Helper {
  50
  51     private final static Logger logger = LoggerFactory.getLogger(GroupV2Helper.class);
  52
  53     private final ProfileKeyCredentialProvider profileKeyCredentialProvider;
  54
  55     private final ProfileProvider profileProvider;
  56
  57     private final SelfRecipientIdProvider selfRecipientIdProvider;
  58
  59     private final GroupsV2Operations groupsV2Operations;
  60
  61     private final GroupsV2Api groupsV2Api;
  62
  63     private final SignalServiceAddressResolver addressResolver;
  64
  65     public GroupV2Helper(
  66             final ProfileKeyCredentialProvider profileKeyCredentialProvider,
  67             final ProfileProvider profileProvider,
  68             final SelfRecipientIdProvider selfRecipientIdProvider,
  69             final GroupsV2Operations groupsV2Operations,
  70             final GroupsV2Api groupsV2Api,
  71             final SignalServiceAddressResolver addressResolver
  72     ) {
  73         this.profileKeyCredentialProvider = profileKeyCredentialProvider;
  74         this.profileProvider = profileProvider;
  75         this.selfRecipientIdProvider = selfRecipientIdProvider;
  76         this.groupsV2Operations = groupsV2Operations;
  77         this.groupsV2Api = groupsV2Api;
  78         this.addressResolver = addressResolver;
  79     }
  80
  81     public DecryptedGroup getDecryptedGroup(final GroupSecretParams groupSecretParams) {
  82         try {
  83             final var groupsV2AuthorizationString = getGroupAuthForToday(groupSecretParams);
  84             return groupsV2Api.getGroup(groupSecretParams, groupsV2AuthorizationString);
  85         } catch (IOException | VerificationFailedException | InvalidGroupStateException e) {
  86             logger.warn("Failed to retrieve Group V2 info, ignoring: {}", e.getMessage());
  87             return null;
  88         }
  89     }
  90
  91     public DecryptedGroupJoinInfo getDecryptedGroupJoinInfo(
  92             GroupMasterKey groupMasterKey, GroupLinkPassword password
  93     ) throws IOException, GroupLinkNotActiveException {
  94         var groupSecretParams = GroupSecretParams.deriveFromMasterKey(groupMasterKey);
  95
  96         return groupsV2Api.getGroupJoinInfo(groupSecretParams,
  97                 Optional.fromNullable(password).transform(GroupLinkPassword::serialize),
  98                 getGroupAuthForToday(groupSecretParams));
  99     }
 100
 101     public Pair<GroupInfoV2, DecryptedGroup> createGroup(
 102             String name, Set<RecipientId> members, File avatarFile
 103     ) throws IOException {
 104         final var avatarBytes = readAvatarBytes(avatarFile);
 105         final var newGroup = buildNewGroup(name, members, avatarBytes);
 106         if (newGroup == null) {
 107             return null;
 108         }
 109
 110         final var groupSecretParams = newGroup.getGroupSecretParams();
 111
 112         final GroupsV2AuthorizationString groupAuthForToday;
 113         final DecryptedGroup decryptedGroup;
 114         try {
 115             groupAuthForToday = getGroupAuthForToday(groupSecretParams);
 116             groupsV2Api.putNewGroup(newGroup, groupAuthForToday);
 117             decryptedGroup = groupsV2Api.getGroup(groupSecretParams, groupAuthForToday);
 118         } catch (IOException | VerificationFailedException | InvalidGroupStateException e) {
 119             logger.warn("Failed to create V2 group: {}", e.getMessage());
 120             return null;
 121         }
 122         if (decryptedGroup == null) {
 123             logger.warn("Failed to create V2 group, unknown error!");
 124             return null;
 125         }
 126
 127         final var groupId = GroupUtils.getGroupIdV2(groupSecretParams);
 128         final var masterKey = groupSecretParams.getMasterKey();
 129         var g = new GroupInfoV2(groupId, masterKey);
 130
 131         return new Pair<>(g, decryptedGroup);
 132     }
 133
 134     private byte[] readAvatarBytes(final File avatarFile) throws IOException {
 135         final byte[] avatarBytes;
 136         try (InputStream avatar = avatarFile == null ? null : new FileInputStream(avatarFile)) {
 137             avatarBytes = avatar == null ? null : IOUtils.readFully(avatar);
 138         }
 139         return avatarBytes;
 140     }
 141
 142     private GroupsV2Operations.NewGroup buildNewGroup(
 143             String name, Set<RecipientId> members, byte[] avatar
 144     ) {
 145         final var profileKeyCredential = profileKeyCredentialProvider.getProfileKeyCredential(selfRecipientIdProvider.getSelfRecipientId());
 146         if (profileKeyCredential == null) {
 147             logger.warn("Cannot create a V2 group as self does not have a versioned profile");
 148             return null;
 149         }
 150
 151         if (!areMembersValid(members)) return null;
 152
 153         var self = new GroupCandidate(getSelfUuid(), Optional.fromNullable(profileKeyCredential));
 154         var candidates = members.stream()
 155                 .map(member -> new GroupCandidate(addressResolver.resolveSignalServiceAddress(member).getUuid(),
 156                         Optional.fromNullable(profileKeyCredentialProvider.getProfileKeyCredential(member))))
 157                 .collect(Collectors.toSet());
 158
 159         final var groupSecretParams = GroupSecretParams.generate();
 160         return groupsV2Operations.createNewGroup(groupSecretParams,
 161                 name,
 162                 Optional.fromNullable(avatar),
 163                 self,
 164                 candidates,
 165                 Member.Role.DEFAULT,
 166                 0);
 167     }
 168
 169     private boolean areMembersValid(final Set<RecipientId> members) {
 170         final var noGv2Capability = members.stream()
 171                 .map(profileProvider::getProfile)
 172                 .filter(profile -> profile != null && !profile.getCapabilities().contains(Profile.Capability.gv2))
 173                 .collect(Collectors.toSet());
 174         if (noGv2Capability.size() > 0) {
 175             logger.warn("Cannot create a V2 group as some members don't support Groups V2: {}",
 176                     noGv2Capability.stream().map(Profile::getDisplayName).collect(Collectors.joining(", ")));
 177             return false;
 178         }
 179
 180         return true;
 181     }
 182
 183     public Pair<DecryptedGroup, GroupChange> updateGroup(
 184             GroupInfoV2 groupInfoV2, String name, String description, File avatarFile
 185     ) throws IOException {
 186         final var groupSecretParams = GroupSecretParams.deriveFromMasterKey(groupInfoV2.getMasterKey());
 187         var groupOperations = groupsV2Operations.forGroup(groupSecretParams);
 188
 189         var change = name != null ? groupOperations.createModifyGroupTitle(name) : GroupChange.Actions.newBuilder();
 190
 191         if (description != null) {
 192             change.setModifyDescription(groupOperations.createModifyGroupDescriptionAction(description));
 193         }
 194
 195         if (avatarFile != null) {
 196             final var avatarBytes = readAvatarBytes(avatarFile);
 197             var avatarCdnKey = groupsV2Api.uploadAvatar(avatarBytes,
 198                     groupSecretParams,
 199                     getGroupAuthForToday(groupSecretParams));
 200             change.setModifyAvatar(GroupChange.Actions.ModifyAvatarAction.newBuilder().setAvatar(avatarCdnKey));
 201         }
 202
 203         final var uuid = getSelfUuid();
 204         change.setSourceUuid(UuidUtil.toByteString(uuid));
 205
 206         return commitChange(groupInfoV2, change);
 207     }
 208
 209     public Pair<DecryptedGroup, GroupChange> addMembers(
 210             GroupInfoV2 groupInfoV2, Set<RecipientId> newMembers
 211     ) throws IOException {
 212         GroupsV2Operations.GroupOperations groupOperations = getGroupOperations(groupInfoV2);
 213
 214         if (!areMembersValid(newMembers)) {
 215             throw new IOException("Failed to update group");
 216         }
 217
 218         var candidates = newMembers.stream()
 219                 .map(member -> new GroupCandidate(addressResolver.resolveSignalServiceAddress(member).getUuid(),
 220                         Optional.fromNullable(profileKeyCredentialProvider.getProfileKeyCredential(member))))
 221                 .collect(Collectors.toSet());
 222
 223         final var uuid = getSelfUuid();
 224         final var change = groupOperations.createModifyGroupMembershipChange(candidates, uuid);
 225
 226         change.setSourceUuid(UuidUtil.toByteString(uuid));
 227
 228         return commitChange(groupInfoV2, change);
 229     }
 230
 231     public Pair<DecryptedGroup, GroupChange> leaveGroup(
 232             GroupInfoV2 groupInfoV2, Set<RecipientId> membersToMakeAdmin
 233     ) throws IOException {
 234         var pendingMembersList = groupInfoV2.getGroup().getPendingMembersList();
 235         final var selfUuid = getSelfUuid();
 236         var selfPendingMember = DecryptedGroupUtil.findPendingByUuid(pendingMembersList, selfUuid);
 237
 238         if (selfPendingMember.isPresent()) {
 239             return revokeInvites(groupInfoV2, Set.of(selfPendingMember.get()));
 240         }
 241
 242         final var adminUuids = membersToMakeAdmin.stream()
 243                 .map(addressResolver::resolveSignalServiceAddress)
 244                 .map(SignalServiceAddress::getUuid)
 245                 .collect(Collectors.toList());
 246         final GroupsV2Operations.GroupOperations groupOperations = getGroupOperations(groupInfoV2);
 247         return commitChange(groupInfoV2, groupOperations.createLeaveAndPromoteMembersToAdmin(selfUuid, adminUuids));
 248     }
 249
 250     public Pair<DecryptedGroup, GroupChange> removeMembers(
 251             GroupInfoV2 groupInfoV2, Set<RecipientId> members
 252     ) throws IOException {
 253         final var memberUuids = members.stream()
 254                 .map(addressResolver::resolveSignalServiceAddress)
 255                 .map(SignalServiceAddress::getUuid)
 256                 .collect(Collectors.toSet());
 257         return ejectMembers(groupInfoV2, memberUuids);
 258     }
 259
 260     public Pair<DecryptedGroup, GroupChange> revokeInvitedMembers(
 261             GroupInfoV2 groupInfoV2, Set<RecipientId> members
 262     ) throws IOException {
 263         var pendingMembersList = groupInfoV2.getGroup().getPendingMembersList();
 264         final var memberUuids = members.stream()
 265                 .map(addressResolver::resolveSignalServiceAddress)
 266                 .map(SignalServiceAddress::getUuid)
 267                 .map(uuid -> DecryptedGroupUtil.findPendingByUuid(pendingMembersList, uuid))
 268                 .filter(Optional::isPresent)
 269                 .map(Optional::get)
 270                 .collect(Collectors.toSet());
 271         return revokeInvites(groupInfoV2, memberUuids);
 272     }
 273
 274     public Pair<DecryptedGroup, GroupChange> resetGroupLinkPassword(GroupInfoV2 groupInfoV2) throws IOException {
 275         final GroupsV2Operations.GroupOperations groupOperations = getGroupOperations(groupInfoV2);
 276         final var newGroupLinkPassword = GroupLinkPassword.createNew().serialize();
 277         final var change = groupOperations.createModifyGroupLinkPasswordChange(newGroupLinkPassword);
 278         return commitChange(groupInfoV2, change);
 279     }
 280
 281     public Pair<DecryptedGroup, GroupChange> setGroupLinkState(
 282             GroupInfoV2 groupInfoV2, GroupLinkState state
 283     ) throws IOException {
 284         final GroupsV2Operations.GroupOperations groupOperations = getGroupOperations(groupInfoV2);
 285
 286         final var accessRequired = toAccessControl(state);
 287         final var requiresNewPassword = state != GroupLinkState.DISABLED && groupInfoV2.getGroup()
 288                 .getInviteLinkPassword()
 289                 .isEmpty();
 290
 291         final var change = requiresNewPassword ? groupOperations.createModifyGroupLinkPasswordAndRightsChange(
 292                 GroupLinkPassword.createNew().serialize(),
 293                 accessRequired) : groupOperations.createChangeJoinByLinkRights(accessRequired);
 294         return commitChange(groupInfoV2, change);
 295     }
 296
 297     public Pair<DecryptedGroup, GroupChange> setEditDetailsPermission(
 298             GroupInfoV2 groupInfoV2, GroupPermission permission
 299     ) throws IOException {
 300         final GroupsV2Operations.GroupOperations groupOperations = getGroupOperations(groupInfoV2);
 301
 302         final var accessRequired = toAccessControl(permission);
 303         final var change = groupOperations.createChangeAttributesRights(accessRequired);
 304         return commitChange(groupInfoV2, change);
 305     }
 306
 307     public Pair<DecryptedGroup, GroupChange> setAddMemberPermission(
 308             GroupInfoV2 groupInfoV2, GroupPermission permission
 309     ) throws IOException {
 310         final GroupsV2Operations.GroupOperations groupOperations = getGroupOperations(groupInfoV2);
 311
 312         final var accessRequired = toAccessControl(permission);
 313         final var change = groupOperations.createChangeMembershipRights(accessRequired);
 314         return commitChange(groupInfoV2, change);
 315     }
 316
 317     public GroupChange joinGroup(
 318             GroupMasterKey groupMasterKey,
 319             GroupLinkPassword groupLinkPassword,
 320             DecryptedGroupJoinInfo decryptedGroupJoinInfo
 321     ) throws IOException {
 322         final var groupSecretParams = GroupSecretParams.deriveFromMasterKey(groupMasterKey);
 323         final var groupOperations = groupsV2Operations.forGroup(groupSecretParams);
 324
 325         final var selfRecipientId = this.selfRecipientIdProvider.getSelfRecipientId();
 326         final var profileKeyCredential = profileKeyCredentialProvider.getProfileKeyCredential(selfRecipientId);
 327         if (profileKeyCredential == null) {
 328             throw new IOException("Cannot join a V2 group as self does not have a versioned profile");
 329         }
 330
 331         var requestToJoin = decryptedGroupJoinInfo.getAddFromInviteLink() == AccessControl.AccessRequired.ADMINISTRATOR;
 332         var change = requestToJoin
 333                 ? groupOperations.createGroupJoinRequest(profileKeyCredential)
 334                 : groupOperations.createGroupJoinDirect(profileKeyCredential);
 335
 336         change.setSourceUuid(UuidUtil.toByteString(addressResolver.resolveSignalServiceAddress(selfRecipientId)
 337                 .getUuid()));
 338
 339         return commitChange(groupSecretParams, decryptedGroupJoinInfo.getRevision(), change, groupLinkPassword);
 340     }
 341
 342     public Pair<DecryptedGroup, GroupChange> acceptInvite(GroupInfoV2 groupInfoV2) throws IOException {
 343         final GroupsV2Operations.GroupOperations groupOperations = getGroupOperations(groupInfoV2);
 344
 345         final var selfRecipientId = this.selfRecipientIdProvider.getSelfRecipientId();
 346         final var profileKeyCredential = profileKeyCredentialProvider.getProfileKeyCredential(selfRecipientId);
 347         if (profileKeyCredential == null) {
 348             throw new IOException("Cannot join a V2 group as self does not have a versioned profile");
 349         }
 350
 351         final var change = groupOperations.createAcceptInviteChange(profileKeyCredential);
 352
 353         final var uuid = addressResolver.resolveSignalServiceAddress(selfRecipientId).getUuid();
 354         change.setSourceUuid(UuidUtil.toByteString(uuid));
 355
 356         return commitChange(groupInfoV2, change);
 357     }
 358
 359     public Pair<DecryptedGroup, GroupChange> setMemberAdmin(
 360             GroupInfoV2 groupInfoV2, RecipientId recipientId, boolean admin
 361     ) throws IOException {
 362         final GroupsV2Operations.GroupOperations groupOperations = getGroupOperations(groupInfoV2);
 363         final var address = addressResolver.resolveSignalServiceAddress(recipientId);
 364         final var newRole = admin ? Member.Role.ADMINISTRATOR : Member.Role.DEFAULT;
 365         final var change = groupOperations.createChangeMemberRole(address.getUuid(), newRole);
 366         return commitChange(groupInfoV2, change);
 367     }
 368
 369     public Pair<DecryptedGroup, GroupChange> setMessageExpirationTimer(
 370             GroupInfoV2 groupInfoV2, int messageExpirationTimer
 371     ) throws IOException {
 372         final GroupsV2Operations.GroupOperations groupOperations = getGroupOperations(groupInfoV2);
 373         final var change = groupOperations.createModifyGroupTimerChange(messageExpirationTimer);
 374         return commitChange(groupInfoV2, change);
 375     }
 376
 377     public Pair<DecryptedGroup, GroupChange> setIsAnnouncementGroup(
 378             GroupInfoV2 groupInfoV2, boolean isAnnouncementGroup
 379     ) throws IOException {
 380         final GroupsV2Operations.GroupOperations groupOperations = getGroupOperations(groupInfoV2);
 381         final var change = groupOperations.createAnnouncementGroupChange(isAnnouncementGroup);
 382         return commitChange(groupInfoV2, change);
 383     }
 384
 385     private AccessControl.AccessRequired toAccessControl(final GroupLinkState state) {
 386         switch (state) {
 387             case DISABLED:
 388                 return AccessControl.AccessRequired.UNSATISFIABLE;
 389             case ENABLED:
 390                 return AccessControl.AccessRequired.ANY;
 391             case ENABLED_WITH_APPROVAL:
 392                 return AccessControl.AccessRequired.ADMINISTRATOR;
 393             default:
 394                 throw new AssertionError();
 395         }
 396     }
 397
 398     private AccessControl.AccessRequired toAccessControl(final GroupPermission permission) {
 399         switch (permission) {
 400             case EVERY_MEMBER:
 401                 return AccessControl.AccessRequired.MEMBER;
 402             case ONLY_ADMINS:
 403                 return AccessControl.AccessRequired.ADMINISTRATOR;
 404             default:
 405                 throw new AssertionError();
 406         }
 407     }
 408
 409     private GroupsV2Operations.GroupOperations getGroupOperations(final GroupInfoV2 groupInfoV2) {
 410         final var groupSecretParams = GroupSecretParams.deriveFromMasterKey(groupInfoV2.getMasterKey());
 411         return groupsV2Operations.forGroup(groupSecretParams);
 412     }
 413
 414     private Pair<DecryptedGroup, GroupChange> revokeInvites(
 415             GroupInfoV2 groupInfoV2, Set<DecryptedPendingMember> pendingMembers
 416     ) throws IOException {
 417         final GroupsV2Operations.GroupOperations groupOperations = getGroupOperations(groupInfoV2);
 418         final var uuidCipherTexts = pendingMembers.stream().map(member -> {
 419             try {
 420                 return new UuidCiphertext(member.getUuidCipherText().toByteArray());
 421             } catch (InvalidInputException e) {
 422                 throw new AssertionError(e);
 423             }
 424         }).collect(Collectors.toSet());
 425         return commitChange(groupInfoV2, groupOperations.createRemoveInvitationChange(uuidCipherTexts));
 426     }
 427
 428     private Pair<DecryptedGroup, GroupChange> ejectMembers(
 429             GroupInfoV2 groupInfoV2, Set<UUID> uuids
 430     ) throws IOException {
 431         final GroupsV2Operations.GroupOperations groupOperations = getGroupOperations(groupInfoV2);
 432         return commitChange(groupInfoV2, groupOperations.createRemoveMembersChange(uuids));
 433     }
 434
 435     private Pair<DecryptedGroup, GroupChange> commitChange(
 436             GroupInfoV2 groupInfoV2, GroupChange.Actions.Builder change
 437     ) throws IOException {
 438         final var groupSecretParams = GroupSecretParams.deriveFromMasterKey(groupInfoV2.getMasterKey());
 439         final var groupOperations = groupsV2Operations.forGroup(groupSecretParams);
 440         final var previousGroupState = groupInfoV2.getGroup();
 441         final var nextRevision = previousGroupState.getRevision() + 1;
 442         final var changeActions = change.setRevision(nextRevision).build();
 443         final DecryptedGroupChange decryptedChange;
 444         final DecryptedGroup decryptedGroupState;
 445
 446         try {
 447             decryptedChange = groupOperations.decryptChange(changeActions, getSelfUuid());
 448             decryptedGroupState = DecryptedGroupUtil.apply(previousGroupState, decryptedChange);
 449         } catch (VerificationFailedException | InvalidGroupStateException | NotAbleToApplyGroupV2ChangeException e) {
 450             throw new IOException(e);
 451         }
 452
 453         var signedGroupChange = groupsV2Api.patchGroup(changeActions,
 454                 getGroupAuthForToday(groupSecretParams),
 455                 Optional.absent());
 456
 457         return new Pair<>(decryptedGroupState, signedGroupChange);
 458     }
 459
 460     private GroupChange commitChange(
 461             GroupSecretParams groupSecretParams,
 462             int currentRevision,
 463             GroupChange.Actions.Builder change,
 464             GroupLinkPassword password
 465     ) throws IOException {
 466         final var nextRevision = currentRevision + 1;
 467         final var changeActions = change.setRevision(nextRevision).build();
 468
 469         return groupsV2Api.patchGroup(changeActions,
 470                 getGroupAuthForToday(groupSecretParams),
 471                 Optional.fromNullable(password).transform(GroupLinkPassword::serialize));
 472     }
 473
 474     public DecryptedGroup getUpdatedDecryptedGroup(
 475             DecryptedGroup group, byte[] signedGroupChange, GroupMasterKey groupMasterKey
 476     ) {
 477         try {
 478             final var decryptedGroupChange = getDecryptedGroupChange(signedGroupChange, groupMasterKey);
 479             if (decryptedGroupChange == null) {
 480                 return null;
 481             }
 482             return DecryptedGroupUtil.apply(group, decryptedGroupChange);
 483         } catch (NotAbleToApplyGroupV2ChangeException e) {
 484             return null;
 485         }
 486     }
 487
 488     private DecryptedGroupChange getDecryptedGroupChange(byte[] signedGroupChange, GroupMasterKey groupMasterKey) {
 489         if (signedGroupChange != null) {
 490             var groupOperations = groupsV2Operations.forGroup(GroupSecretParams.deriveFromMasterKey(groupMasterKey));
 491
 492             try {
 493                 return groupOperations.decryptChange(GroupChange.parseFrom(signedGroupChange), true).orNull();
 494             } catch (VerificationFailedException | InvalidGroupStateException | InvalidProtocolBufferException e) {
 495                 return null;
 496             }
 497         }
 498
 499         return null;
 500     }
 501
 502     private static int currentTimeDays() {
 503         return (int) TimeUnit.MILLISECONDS.toDays(System.currentTimeMillis());
 504     }
 505
 506     private GroupsV2AuthorizationString getGroupAuthForToday(
 507             final GroupSecretParams groupSecretParams
 508     ) throws IOException {
 509         final var today = currentTimeDays();
 510         // Returns credentials for the next 7 days
 511         final var credentials = groupsV2Api.getCredentials(today);
 512         // TODO cache credentials until they expire
 513         var authCredentialResponse = credentials.get(today);
 514         final var uuid = getSelfUuid();
 515         try {
 516             return groupsV2Api.getGroupsV2AuthorizationString(uuid, today, groupSecretParams, authCredentialResponse);
 517         } catch (VerificationFailedException e) {
 518             throw new IOException(e);
 519         }
 520     }
 521
 522     private UUID getSelfUuid() {
 523         return addressResolver.resolveSignalServiceAddress(this.selfRecipientIdProvider.getSelfRecipientId()).getUuid();
 524     }
 525 }