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.SignalDependencies;
   6 import org.asamk.signal.manager.api.Pair;
   7 import org.asamk.signal.manager.groups.GroupLinkPassword;
   8 import org.asamk.signal.manager.groups.GroupLinkState;
   9 import org.asamk.signal.manager.groups.GroupPermission;
  10 import org.asamk.signal.manager.groups.GroupUtils;
  11 import org.asamk.signal.manager.groups.NotAGroupMemberException;
  12 import org.asamk.signal.manager.storage.groups.GroupInfoV2;
  13 import org.asamk.signal.manager.storage.recipients.RecipientId;
  14 import org.asamk.signal.manager.util.IOUtils;
  15 import org.asamk.signal.manager.util.Utils;
  16 import org.signal.storageservice.protos.groups.AccessControl;
  17 import org.signal.storageservice.protos.groups.GroupChange;
  18 import org.signal.storageservice.protos.groups.Member;
  19 import org.signal.storageservice.protos.groups.local.DecryptedGroup;
  20 import org.signal.storageservice.protos.groups.local.DecryptedGroupChange;
  21 import org.signal.storageservice.protos.groups.local.DecryptedGroupJoinInfo;
  22 import org.signal.storageservice.protos.groups.local.DecryptedPendingMember;
  23 import org.signal.zkgroup.InvalidInputException;
  24 import org.signal.zkgroup.VerificationFailedException;
  25 import org.signal.zkgroup.auth.AuthCredentialResponse;
  26 import org.signal.zkgroup.groups.GroupMasterKey;
  27 import org.signal.zkgroup.groups.GroupSecretParams;
  28 import org.signal.zkgroup.groups.UuidCiphertext;
  29 import org.slf4j.Logger;
  30 import org.slf4j.LoggerFactory;
  31 import org.whispersystems.signalservice.api.groupsv2.DecryptedGroupUtil;
  32 import org.whispersystems.signalservice.api.groupsv2.GroupCandidate;
  33 import org.whispersystems.signalservice.api.groupsv2.GroupLinkNotActiveException;
  34 import org.whispersystems.signalservice.api.groupsv2.GroupsV2AuthorizationString;
  35 import org.whispersystems.signalservice.api.groupsv2.GroupsV2Operations;
  36 import org.whispersystems.signalservice.api.groupsv2.InvalidGroupStateException;
  37 import org.whispersystems.signalservice.api.groupsv2.NotAbleToApplyGroupV2ChangeException;
  38 import org.whispersystems.signalservice.api.push.ACI;
  39 import org.whispersystems.signalservice.api.push.ServiceId;
  40 import org.whispersystems.signalservice.api.push.SignalServiceAddress;
  41 import org.whispersystems.signalservice.api.push.exceptions.NonSuccessfulResponseCodeException;
  42
  43 import java.io.File;
  44 import java.io.FileInputStream;
  45 import java.io.IOException;
  46 import java.io.InputStream;
  47 import java.util.ArrayList;
  48 import java.util.HashMap;
  49 import java.util.Optional;
  50 import java.util.Set;
  51 import java.util.UUID;
  52 import java.util.concurrent.TimeUnit;
  53 import java.util.stream.Collectors;
  54
  55 class GroupV2Helper {
  56
  57     private final static Logger logger = LoggerFactory.getLogger(GroupV2Helper.class);
  58
  59     private final SignalDependencies dependencies;
  60     private final Context context;
  61
  62     private HashMap<Integer, AuthCredentialResponse> groupApiCredentials;
  63
  64     GroupV2Helper(final Context context) {
  65         this.dependencies = context.getDependencies();
  66         this.context = context;
  67     }
  68
  69     DecryptedGroup getDecryptedGroup(final GroupSecretParams groupSecretParams) throws NotAGroupMemberException {
  70         try {
  71             final var groupsV2AuthorizationString = getGroupAuthForToday(groupSecretParams);
  72             return dependencies.getGroupsV2Api().getGroup(groupSecretParams, groupsV2AuthorizationString);
  73         } catch (NonSuccessfulResponseCodeException e) {
  74             if (e.getCode() == 403) {
  75                 throw new NotAGroupMemberException(GroupUtils.getGroupIdV2(groupSecretParams), null);
  76             }
  77             logger.warn("Failed to retrieve Group V2 info, ignoring: {}", e.getMessage());
  78             return null;
  79         } catch (IOException | VerificationFailedException | InvalidGroupStateException e) {
  80             logger.warn("Failed to retrieve Group V2 info, ignoring: {}", e.getMessage());
  81             return null;
  82         }
  83     }
  84
  85     DecryptedGroupJoinInfo getDecryptedGroupJoinInfo(
  86             GroupMasterKey groupMasterKey, GroupLinkPassword password
  87     ) throws IOException, GroupLinkNotActiveException {
  88         var groupSecretParams = GroupSecretParams.deriveFromMasterKey(groupMasterKey);
  89
  90         return dependencies.getGroupsV2Api()
  91                 .getGroupJoinInfo(groupSecretParams,
  92                         Optional.ofNullable(password).map(GroupLinkPassword::serialize),
  93                         getGroupAuthForToday(groupSecretParams));
  94     }
  95
  96     Pair<GroupInfoV2, DecryptedGroup> createGroup(
  97             String name, Set<RecipientId> members, File avatarFile
  98     ) throws IOException {
  99         final var avatarBytes = readAvatarBytes(avatarFile);
 100         final var newGroup = buildNewGroup(name, members, avatarBytes);
 101         if (newGroup == null) {
 102             return null;
 103         }
 104
 105         final var groupSecretParams = newGroup.getGroupSecretParams();
 106
 107         final GroupsV2AuthorizationString groupAuthForToday;
 108         final DecryptedGroup decryptedGroup;
 109         try {
 110             groupAuthForToday = getGroupAuthForToday(groupSecretParams);
 111             dependencies.getGroupsV2Api().putNewGroup(newGroup, groupAuthForToday);
 112             decryptedGroup = dependencies.getGroupsV2Api().getGroup(groupSecretParams, groupAuthForToday);
 113         } catch (IOException | VerificationFailedException | InvalidGroupStateException e) {
 114             logger.warn("Failed to create V2 group: {}", e.getMessage());
 115             return null;
 116         }
 117         if (decryptedGroup == null) {
 118             logger.warn("Failed to create V2 group, unknown error!");
 119             return null;
 120         }
 121
 122         final var groupId = GroupUtils.getGroupIdV2(groupSecretParams);
 123         final var masterKey = groupSecretParams.getMasterKey();
 124         var g = new GroupInfoV2(groupId, masterKey);
 125
 126         return new Pair<>(g, decryptedGroup);
 127     }
 128
 129     private byte[] readAvatarBytes(final File avatarFile) throws IOException {
 130         final byte[] avatarBytes;
 131         try (InputStream avatar = avatarFile == null ? null : new FileInputStream(avatarFile)) {
 132             avatarBytes = avatar == null ? null : IOUtils.readFully(avatar);
 133         }
 134         return avatarBytes;
 135     }
 136
 137     private GroupsV2Operations.NewGroup buildNewGroup(
 138             String name, Set<RecipientId> members, byte[] avatar
 139     ) {
 140         final var profileKeyCredential = context.getProfileHelper()
 141                 .getRecipientProfileKeyCredential(context.getAccount().getSelfRecipientId());
 142         if (profileKeyCredential == null) {
 143             logger.warn("Cannot create a V2 group as self does not have a versioned profile");
 144             return null;
 145         }
 146
 147         final var self = new GroupCandidate(getSelfAci().uuid(), Optional.of(profileKeyCredential));
 148         final var memberList = new ArrayList<>(members);
 149         final var credentials = context.getProfileHelper().getRecipientProfileKeyCredential(memberList).stream();
 150         final var uuids = memberList.stream()
 151                 .map(member -> context.getRecipientHelper().resolveSignalServiceAddress(member).getServiceId().uuid());
 152         var candidates = Utils.zip(uuids,
 153                         credentials,
 154                         (uuid, credential) -> new GroupCandidate(uuid, Optional.ofNullable(credential)))
 155                 .collect(Collectors.toSet());
 156
 157         final var groupSecretParams = GroupSecretParams.generate();
 158         return dependencies.getGroupsV2Operations()
 159                 .createNewGroup(groupSecretParams,
 160                         name,
 161                         Optional.ofNullable(avatar),
 162                         self,
 163                         candidates,
 164                         Member.Role.DEFAULT,
 165                         0);
 166     }
 167
 168     Pair<DecryptedGroup, GroupChange> updateGroup(
 169             GroupInfoV2 groupInfoV2, String name, String description, File avatarFile
 170     ) throws IOException {
 171         final var groupSecretParams = GroupSecretParams.deriveFromMasterKey(groupInfoV2.getMasterKey());
 172         var groupOperations = dependencies.getGroupsV2Operations().forGroup(groupSecretParams);
 173
 174         var change = name != null ? groupOperations.createModifyGroupTitle(name) : GroupChange.Actions.newBuilder();
 175
 176         if (description != null) {
 177             change.setModifyDescription(groupOperations.createModifyGroupDescriptionAction(description));
 178         }
 179
 180         if (avatarFile != null) {
 181             final var avatarBytes = readAvatarBytes(avatarFile);
 182             var avatarCdnKey = dependencies.getGroupsV2Api()
 183                     .uploadAvatar(avatarBytes, groupSecretParams, getGroupAuthForToday(groupSecretParams));
 184             change.setModifyAvatar(GroupChange.Actions.ModifyAvatarAction.newBuilder().setAvatar(avatarCdnKey));
 185         }
 186
 187         change.setSourceUuid(getSelfAci().toByteString());
 188
 189         return commitChange(groupInfoV2, change);
 190     }
 191
 192     Pair<DecryptedGroup, GroupChange> addMembers(
 193             GroupInfoV2 groupInfoV2, Set<RecipientId> newMembers
 194     ) throws IOException {
 195         GroupsV2Operations.GroupOperations groupOperations = getGroupOperations(groupInfoV2);
 196
 197         final var memberList = new ArrayList<>(newMembers);
 198         final var credentials = context.getProfileHelper().getRecipientProfileKeyCredential(memberList).stream();
 199         final var uuids = memberList.stream()
 200                 .map(member -> context.getRecipientHelper().resolveSignalServiceAddress(member).getServiceId().uuid());
 201         var candidates = Utils.zip(uuids,
 202                         credentials,
 203                         (uuid, credential) -> new GroupCandidate(uuid, Optional.ofNullable(credential)))
 204                 .collect(Collectors.toSet());
 205
 206         final var aci = getSelfAci();
 207         final var change = groupOperations.createModifyGroupMembershipChange(candidates, Set.of(), aci.uuid());
 208
 209         change.setSourceUuid(getSelfAci().toByteString());
 210
 211         return commitChange(groupInfoV2, change);
 212     }
 213
 214     Pair<DecryptedGroup, GroupChange> leaveGroup(
 215             GroupInfoV2 groupInfoV2, Set<RecipientId> membersToMakeAdmin
 216     ) throws IOException {
 217         var pendingMembersList = groupInfoV2.getGroup().getPendingMembersList();
 218         final var selfAci = getSelfAci();
 219         var selfPendingMember = DecryptedGroupUtil.findPendingByUuid(pendingMembersList, selfAci.uuid());
 220
 221         if (selfPendingMember.isPresent()) {
 222             return revokeInvites(groupInfoV2, Set.of(selfPendingMember.get()));
 223         }
 224
 225         final var adminUuids = membersToMakeAdmin.stream()
 226                 .map(context.getRecipientHelper()::resolveSignalServiceAddress)
 227                 .map(SignalServiceAddress::getServiceId)
 228                 .map(ServiceId::uuid)
 229                 .toList();
 230         final GroupsV2Operations.GroupOperations groupOperations = getGroupOperations(groupInfoV2);
 231         return commitChange(groupInfoV2,
 232                 groupOperations.createLeaveAndPromoteMembersToAdmin(selfAci.uuid(), adminUuids));
 233     }
 234
 235     Pair<DecryptedGroup, GroupChange> removeMembers(
 236             GroupInfoV2 groupInfoV2, Set<RecipientId> members
 237     ) throws IOException {
 238         final var memberUuids = members.stream()
 239                 .map(context.getRecipientHelper()::resolveSignalServiceAddress)
 240                 .map(SignalServiceAddress::getServiceId)
 241                 .map(ServiceId::uuid)
 242                 .collect(Collectors.toSet());
 243         return ejectMembers(groupInfoV2, memberUuids);
 244     }
 245
 246     Pair<DecryptedGroup, GroupChange> revokeInvitedMembers(
 247             GroupInfoV2 groupInfoV2, Set<RecipientId> members
 248     ) throws IOException {
 249         var pendingMembersList = groupInfoV2.getGroup().getPendingMembersList();
 250         final var memberUuids = members.stream()
 251                 .map(context.getRecipientHelper()::resolveSignalServiceAddress)
 252                 .map(SignalServiceAddress::getServiceId)
 253                 .map(ServiceId::uuid)
 254                 .map(uuid -> DecryptedGroupUtil.findPendingByUuid(pendingMembersList, uuid))
 255                 .filter(Optional::isPresent)
 256                 .map(Optional::get)
 257                 .collect(Collectors.toSet());
 258         return revokeInvites(groupInfoV2, memberUuids);
 259     }
 260
 261     Pair<DecryptedGroup, GroupChange> resetGroupLinkPassword(GroupInfoV2 groupInfoV2) throws IOException {
 262         final GroupsV2Operations.GroupOperations groupOperations = getGroupOperations(groupInfoV2);
 263         final var newGroupLinkPassword = GroupLinkPassword.createNew().serialize();
 264         final var change = groupOperations.createModifyGroupLinkPasswordChange(newGroupLinkPassword);
 265         return commitChange(groupInfoV2, change);
 266     }
 267
 268     Pair<DecryptedGroup, GroupChange> setGroupLinkState(
 269             GroupInfoV2 groupInfoV2, GroupLinkState state
 270     ) throws IOException {
 271         final GroupsV2Operations.GroupOperations groupOperations = getGroupOperations(groupInfoV2);
 272
 273         final var accessRequired = toAccessControl(state);
 274         final var requiresNewPassword = state != GroupLinkState.DISABLED && groupInfoV2.getGroup()
 275                 .getInviteLinkPassword()
 276                 .isEmpty();
 277
 278         final var change = requiresNewPassword ? groupOperations.createModifyGroupLinkPasswordAndRightsChange(
 279                 GroupLinkPassword.createNew().serialize(),
 280                 accessRequired) : groupOperations.createChangeJoinByLinkRights(accessRequired);
 281         return commitChange(groupInfoV2, change);
 282     }
 283
 284     Pair<DecryptedGroup, GroupChange> setEditDetailsPermission(
 285             GroupInfoV2 groupInfoV2, GroupPermission permission
 286     ) throws IOException {
 287         final GroupsV2Operations.GroupOperations groupOperations = getGroupOperations(groupInfoV2);
 288
 289         final var accessRequired = toAccessControl(permission);
 290         final var change = groupOperations.createChangeAttributesRights(accessRequired);
 291         return commitChange(groupInfoV2, change);
 292     }
 293
 294     Pair<DecryptedGroup, GroupChange> setAddMemberPermission(
 295             GroupInfoV2 groupInfoV2, GroupPermission permission
 296     ) throws IOException {
 297         final GroupsV2Operations.GroupOperations groupOperations = getGroupOperations(groupInfoV2);
 298
 299         final var accessRequired = toAccessControl(permission);
 300         final var change = groupOperations.createChangeMembershipRights(accessRequired);
 301         return commitChange(groupInfoV2, change);
 302     }
 303
 304     GroupChange joinGroup(
 305             GroupMasterKey groupMasterKey,
 306             GroupLinkPassword groupLinkPassword,
 307             DecryptedGroupJoinInfo decryptedGroupJoinInfo
 308     ) throws IOException {
 309         final var groupSecretParams = GroupSecretParams.deriveFromMasterKey(groupMasterKey);
 310         final var groupOperations = dependencies.getGroupsV2Operations().forGroup(groupSecretParams);
 311
 312         final var selfRecipientId = context.getAccount().getSelfRecipientId();
 313         final var profileKeyCredential = context.getProfileHelper().getRecipientProfileKeyCredential(selfRecipientId);
 314         if (profileKeyCredential == null) {
 315             throw new IOException("Cannot join a V2 group as self does not have a versioned profile");
 316         }
 317
 318         var requestToJoin = decryptedGroupJoinInfo.getAddFromInviteLink() == AccessControl.AccessRequired.ADMINISTRATOR;
 319         var change = requestToJoin
 320                 ? groupOperations.createGroupJoinRequest(profileKeyCredential)
 321                 : groupOperations.createGroupJoinDirect(profileKeyCredential);
 322
 323         change.setSourceUuid(context.getRecipientHelper()
 324                 .resolveSignalServiceAddress(selfRecipientId)
 325                 .getServiceId()
 326                 .toByteString());
 327
 328         return commitChange(groupSecretParams, decryptedGroupJoinInfo.getRevision(), change, groupLinkPassword);
 329     }
 330
 331     Pair<DecryptedGroup, GroupChange> acceptInvite(GroupInfoV2 groupInfoV2) throws IOException {
 332         final GroupsV2Operations.GroupOperations groupOperations = getGroupOperations(groupInfoV2);
 333
 334         final var selfRecipientId = context.getAccount().getSelfRecipientId();
 335         final var profileKeyCredential = context.getProfileHelper().getRecipientProfileKeyCredential(selfRecipientId);
 336         if (profileKeyCredential == null) {
 337             throw new IOException("Cannot join a V2 group as self does not have a versioned profile");
 338         }
 339
 340         final var change = groupOperations.createAcceptInviteChange(profileKeyCredential);
 341
 342         final var aci = context.getRecipientHelper().resolveSignalServiceAddress(selfRecipientId).getServiceId();
 343         change.setSourceUuid(aci.toByteString());
 344
 345         return commitChange(groupInfoV2, change);
 346     }
 347
 348     Pair<DecryptedGroup, GroupChange> setMemberAdmin(
 349             GroupInfoV2 groupInfoV2, RecipientId recipientId, boolean admin
 350     ) throws IOException {
 351         final GroupsV2Operations.GroupOperations groupOperations = getGroupOperations(groupInfoV2);
 352         final var address = context.getRecipientHelper().resolveSignalServiceAddress(recipientId);
 353         final var newRole = admin ? Member.Role.ADMINISTRATOR : Member.Role.DEFAULT;
 354         final var change = groupOperations.createChangeMemberRole(address.getServiceId().uuid(), newRole);
 355         return commitChange(groupInfoV2, change);
 356     }
 357
 358     Pair<DecryptedGroup, GroupChange> setMessageExpirationTimer(
 359             GroupInfoV2 groupInfoV2, int messageExpirationTimer
 360     ) throws IOException {
 361         final GroupsV2Operations.GroupOperations groupOperations = getGroupOperations(groupInfoV2);
 362         final var change = groupOperations.createModifyGroupTimerChange(messageExpirationTimer);
 363         return commitChange(groupInfoV2, change);
 364     }
 365
 366     Pair<DecryptedGroup, GroupChange> setIsAnnouncementGroup(
 367             GroupInfoV2 groupInfoV2, boolean isAnnouncementGroup
 368     ) throws IOException {
 369         final GroupsV2Operations.GroupOperations groupOperations = getGroupOperations(groupInfoV2);
 370         final var change = groupOperations.createAnnouncementGroupChange(isAnnouncementGroup);
 371         return commitChange(groupInfoV2, change);
 372     }
 373
 374     private AccessControl.AccessRequired toAccessControl(final GroupLinkState state) {
 375         return switch (state) {
 376             case DISABLED -> AccessControl.AccessRequired.UNSATISFIABLE;
 377             case ENABLED -> AccessControl.AccessRequired.ANY;
 378             case ENABLED_WITH_APPROVAL -> AccessControl.AccessRequired.ADMINISTRATOR;
 379         };
 380     }
 381
 382     private AccessControl.AccessRequired toAccessControl(final GroupPermission permission) {
 383         return switch (permission) {
 384             case EVERY_MEMBER -> AccessControl.AccessRequired.MEMBER;
 385             case ONLY_ADMINS -> AccessControl.AccessRequired.ADMINISTRATOR;
 386         };
 387     }
 388
 389     private GroupsV2Operations.GroupOperations getGroupOperations(final GroupInfoV2 groupInfoV2) {
 390         final var groupSecretParams = GroupSecretParams.deriveFromMasterKey(groupInfoV2.getMasterKey());
 391         return dependencies.getGroupsV2Operations().forGroup(groupSecretParams);
 392     }
 393
 394     private Pair<DecryptedGroup, GroupChange> revokeInvites(
 395             GroupInfoV2 groupInfoV2, Set<DecryptedPendingMember> pendingMembers
 396     ) throws IOException {
 397         final GroupsV2Operations.GroupOperations groupOperations = getGroupOperations(groupInfoV2);
 398         final var uuidCipherTexts = pendingMembers.stream().map(member -> {
 399             try {
 400                 return new UuidCiphertext(member.getUuidCipherText().toByteArray());
 401             } catch (InvalidInputException e) {
 402                 throw new AssertionError(e);
 403             }
 404         }).collect(Collectors.toSet());
 405         return commitChange(groupInfoV2, groupOperations.createRemoveInvitationChange(uuidCipherTexts));
 406     }
 407
 408     private Pair<DecryptedGroup, GroupChange> ejectMembers(
 409             GroupInfoV2 groupInfoV2, Set<UUID> uuids
 410     ) throws IOException {
 411         final GroupsV2Operations.GroupOperations groupOperations = getGroupOperations(groupInfoV2);
 412         return commitChange(groupInfoV2, groupOperations.createRemoveMembersChange(uuids, false));
 413     }
 414
 415     private Pair<DecryptedGroup, GroupChange> commitChange(
 416             GroupInfoV2 groupInfoV2, GroupChange.Actions.Builder change
 417     ) throws IOException {
 418         final var groupSecretParams = GroupSecretParams.deriveFromMasterKey(groupInfoV2.getMasterKey());
 419         final var groupOperations = dependencies.getGroupsV2Operations().forGroup(groupSecretParams);
 420         final var previousGroupState = groupInfoV2.getGroup();
 421         final var nextRevision = previousGroupState.getRevision() + 1;
 422         final var changeActions = change.setRevision(nextRevision).build();
 423         final DecryptedGroupChange decryptedChange;
 424         final DecryptedGroup decryptedGroupState;
 425
 426         try {
 427             decryptedChange = groupOperations.decryptChange(changeActions, getSelfAci().uuid());
 428             decryptedGroupState = DecryptedGroupUtil.apply(previousGroupState, decryptedChange);
 429         } catch (VerificationFailedException | InvalidGroupStateException | NotAbleToApplyGroupV2ChangeException e) {
 430             throw new IOException(e);
 431         }
 432
 433         var signedGroupChange = dependencies.getGroupsV2Api()
 434                 .patchGroup(changeActions, getGroupAuthForToday(groupSecretParams), Optional.empty());
 435
 436         return new Pair<>(decryptedGroupState, signedGroupChange);
 437     }
 438
 439     private GroupChange commitChange(
 440             GroupSecretParams groupSecretParams,
 441             int currentRevision,
 442             GroupChange.Actions.Builder change,
 443             GroupLinkPassword password
 444     ) throws IOException {
 445         final var nextRevision = currentRevision + 1;
 446         final var changeActions = change.setRevision(nextRevision).build();
 447
 448         return dependencies.getGroupsV2Api()
 449                 .patchGroup(changeActions,
 450                         getGroupAuthForToday(groupSecretParams),
 451                         Optional.ofNullable(password).map(GroupLinkPassword::serialize));
 452     }
 453
 454     DecryptedGroup getUpdatedDecryptedGroup(
 455             DecryptedGroup group, byte[] signedGroupChange, GroupMasterKey groupMasterKey
 456     ) {
 457         try {
 458             final var decryptedGroupChange = getDecryptedGroupChange(signedGroupChange, groupMasterKey);
 459             if (decryptedGroupChange == null) {
 460                 return null;
 461             }
 462             return DecryptedGroupUtil.apply(group, decryptedGroupChange);
 463         } catch (NotAbleToApplyGroupV2ChangeException e) {
 464             return null;
 465         }
 466     }
 467
 468     private DecryptedGroupChange getDecryptedGroupChange(byte[] signedGroupChange, GroupMasterKey groupMasterKey) {
 469         if (signedGroupChange != null) {
 470             var groupOperations = dependencies.getGroupsV2Operations()
 471                     .forGroup(GroupSecretParams.deriveFromMasterKey(groupMasterKey));
 472
 473             try {
 474                 return groupOperations.decryptChange(GroupChange.parseFrom(signedGroupChange), true).orElse(null);
 475             } catch (VerificationFailedException | InvalidGroupStateException | InvalidProtocolBufferException e) {
 476                 return null;
 477             }
 478         }
 479
 480         return null;
 481     }
 482
 483     private static int currentTimeDays() {
 484         return (int) TimeUnit.MILLISECONDS.toDays(System.currentTimeMillis());
 485     }
 486
 487     private GroupsV2AuthorizationString getGroupAuthForToday(
 488             final GroupSecretParams groupSecretParams
 489     ) throws IOException {
 490         final var today = currentTimeDays();
 491         if (groupApiCredentials == null || !groupApiCredentials.containsKey(today)) {
 492             // Returns credentials for the next 7 days
 493             groupApiCredentials = dependencies.getGroupsV2Api().getCredentials(today);
 494             // TODO cache credentials on disk until they expire
 495         }
 496         var authCredentialResponse = groupApiCredentials.get(today);
 497         final var aci = getSelfAci();
 498         try {
 499             return dependencies.getGroupsV2Api()
 500                     .getGroupsV2AuthorizationString(aci, today, groupSecretParams, authCredentialResponse);
 501         } catch (VerificationFailedException e) {
 502             throw new IOException(e);
 503         }
 504     }
 505
 506     private ACI getSelfAci() {
 507         return context.getAccount().getAci();
 508     }
 509 }