Prompt user when inviting users with uncached identities (#5331)

If the user attempts to invite someone (to a room or creating a DM) whose identity is not cached, we prompt them to make sure this was their intention.

AccessibilityTests/Sources/GeneratedAccessibilityTests.swift

@@ -239,6 +239,10 @@ extension AccessibilityTests {
         try await performAccessibilityAudit(named: "ImageRoomTimelineView_Previews")
     }
 
+    func testInviteUsersConfirmationSheetView() async throws {
+        try await performAccessibilityAudit(named: "InviteUsersConfirmationSheetView_Previews")
+    }
+
     func testInviteUsersScreenSelectedItem() async throws {
         try await performAccessibilityAudit(named: "InviteUsersScreenSelectedItem_Previews")
     }

ElementX.xcodeproj/project.pbxproj

@@ -432,6 +432,7 @@
 		4949C8C12669D1B5E082366E /* QRCodeLoginScreen.swift in Sources */ = {isa = PBXBuildFile; fileRef = BFA9EA59D5C0DA1BFC7B3621 /* QRCodeLoginScreen.swift */; };
 		49500BBA1CD65A5AE252D970 /* RoomDirectorySearchScreenModels.swift in Sources */ = {isa = PBXBuildFile; fileRef = 41BB37D96C3EA18F3CE8675D /* RoomDirectorySearchScreenModels.swift */; };
 		49BBEC46D523BF6A41400048 /* URLTests.swift in Sources */ = {isa = PBXBuildFile; fileRef = 3AB34956C87731AB094DB33A /* URLTests.swift */; };
+		4A361E8BAFFA20B9719B47F5 /* InviteUsersConfirmationSheetView.swift in Sources */ = {isa = PBXBuildFile; fileRef = 8E97CF050B0168F3D605F0E9 /* InviteUsersConfirmationSheetView.swift */; };
 		4A4110369DBB79E4A314F415 /* ComposerToolbarViewModelProtocol.swift in Sources */ = {isa = PBXBuildFile; fileRef = B0618820D26F9871A4BBB40E /* ComposerToolbarViewModelProtocol.swift */; };
 		4A618590DEB72C4F186BFED4 /* UserSessionFlowCoordinator.swift in Sources */ = {isa = PBXBuildFile; fileRef = C99FDEEB71173C4C6FA2734C /* UserSessionFlowCoordinator.swift */; };
 		4A8287E5281B44A8754BE509 /* SessionVerificationScreenViewModel.swift in Sources */ = {isa = PBXBuildFile; fileRef = ED33988DA4FD4FC666800106 /* SessionVerificationScreenViewModel.swift */; };
@@ -897,6 +898,7 @@
 		964B9D2EC38C488C360CE0C9 /* HomeScreen.swift in Sources */ = {isa = PBXBuildFile; fileRef = B902EA6CD3296B0E10EE432B /* HomeScreen.swift */; };
 		9696ECAFB4F0C079C5C2A526 /* AppLockSetupPINScreenCoordinator.swift in Sources */ = {isa = PBXBuildFile; fileRef = 1FAF8C2226A57B9AB7446B31 /* AppLockSetupPINScreenCoordinator.swift */; };
 		96B3606E30F824095B1DD022 /* NetworkMonitorMock.swift in Sources */ = {isa = PBXBuildFile; fileRef = 8DA1E8F287680C8ED25EDBAC /* NetworkMonitorMock.swift */; };
+		9707AF8D41667FA9B35E8953 /* UserToInvite.swift in Sources */ = {isa = PBXBuildFile; fileRef = ED25719E19B205B668FDACFF /* UserToInvite.swift */; };
 		97189E495F0E47805D1868DB /* KeychainAccess in Frameworks */ = {isa = PBXBuildFile; productRef = 2B43F2AF7456567FE37270A7 /* KeychainAccess */; };
 		973C48F9E4EFB808F61BE401 /* LocationRoomTimelineView.swift in Sources */ = {isa = PBXBuildFile; fileRef = ED49073BB1C1FC649DAC2CCD /* LocationRoomTimelineView.swift */; };
 		978BB24F2A5D31EE59EEC249 /* UserSessionProtocol.swift in Sources */ = {isa = PBXBuildFile; fileRef = 5F4134FEFE4EB55759017408 /* UserSessionProtocol.swift */; };
@@ -2387,6 +2389,7 @@
 		8DA1E8F287680C8ED25EDBAC /* NetworkMonitorMock.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = NetworkMonitorMock.swift; sourceTree = "<group>"; };
 		8E088F2A1B9EC529D3221931 /* UITests.xctestplan */ = {isa = PBXFileReference; path = UITests.xctestplan; sourceTree = "<group>"; };
 		8E1584F8BCF407BB94F48F04 /* EncryptionResetPasswordScreen.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = EncryptionResetPasswordScreen.swift; sourceTree = "<group>"; };
+		8E97CF050B0168F3D605F0E9 /* InviteUsersConfirmationSheetView.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = InviteUsersConfirmationSheetView.swift; sourceTree = "<group>"; };
 		8EAF4A49F3ACD8BB8B0D2371 /* ClientSDKMock.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = ClientSDKMock.swift; sourceTree = "<group>"; };
 		8F062DD2CCD95DC33528A16F /* KnockRequestProxy.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = KnockRequestProxy.swift; sourceTree = "<group>"; };
 		8F21ED7205048668BEB44A38 /* AppActivityView.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = AppActivityView.swift; sourceTree = "<group>"; };
@@ -2921,6 +2924,7 @@
 		ED0AD0C652385F69FA90FAF5 /* TimelineMediaPreviewDataSourceTests.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = TimelineMediaPreviewDataSourceTests.swift; sourceTree = "<group>"; };
 		ED0CBEAB5F796BEFBAF7BB6A /* VideoRoomTimelineView.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = VideoRoomTimelineView.swift; sourceTree = "<group>"; };
 		ED1D792EB82506A19A72C8DE /* RoomTimelineItemProtocol.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = RoomTimelineItemProtocol.swift; sourceTree = "<group>"; };
+		ED25719E19B205B668FDACFF /* UserToInvite.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = UserToInvite.swift; sourceTree = "<group>"; };
 		ED33988DA4FD4FC666800106 /* SessionVerificationScreenViewModel.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = SessionVerificationScreenViewModel.swift; sourceTree = "<group>"; };
 		ED482057AE39D5C6D9C5F3D8 /* message.caf */ = {isa = PBXFileReference; path = message.caf; sourceTree = "<group>"; };
 		ED49073BB1C1FC649DAC2CCD /* LocationRoomTimelineView.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = LocationRoomTimelineView.swift; sourceTree = "<group>"; };
@@ -4134,6 +4138,7 @@
 				578AF9CE60816069536C0953 /* RoomRole.swift */,
 				CCE06F4A71FD46C9D8CD432E /* RoomThreadListServiceProxy.swift */,
 				04EB6035C1F33F25F1EBFB7D /* RoomThreadListServiceProxyProtocol.swift */,
+				ED25719E19B205B668FDACFF /* UserToInvite.swift */,
 				2C0F49BD446849654C0D24E0 /* RoomMember */,
 				4DC0344D2EBD0AE5D71754A9 /* RoomMembershipDetails */,
 				7FC3F8FA5EA765AC3B000F55 /* RoomPreview */,
@@ -4296,6 +4301,7 @@
 		493225D61FED2DA3D3B26104 /* View */ = {
 			isa = PBXGroup;
 			children = (
+				8E97CF050B0168F3D605F0E9 /* InviteUsersConfirmationSheetView.swift */,
 				C2E9B841EE4878283ECDB554 /* InviteUsersScreen.swift */,
 				10F32E0B4B83D2A11EE8D011 /* InviteUsersScreenSelectedItem.swift */,
 			);
@@ -7325,6 +7331,7 @@
 				};
 			};
 			buildConfigurationList = 7AE41FCCF9D1352E2770D1F9 /* Build configuration list for PBXProject "ElementX" */;
+			compatibilityVersion = "Xcode 14.0";
 			developmentRegion = en;
 			hasScannedForEncodings = 0;
 			knownRegions = (
@@ -7402,7 +7409,6 @@
 				C89CF7729E028671C5DC461E /* XCLocalSwiftPackageReference "compound-ios" */,
 			);
 			preferredProjectObjectVersion = 77;
-			productRefGroup = 681566846AF307E9BA4C72C6 /* Products */;
 			projectDirPath = "";
 			projectRoot = "";
 			targets = (
@@ -8328,6 +8334,7 @@
 				B6048166B4AA4CEFEA9B77A6 /* InfoPlistReader.swift in Sources */,
 				BFEB24336DFD5F196E6F3456 /* IntentionalMentions.swift in Sources */,
 				2AAB2A77F1762A2648078A30 /* InteractiveQuickLook.swift in Sources */,
+				4A361E8BAFFA20B9719B47F5 /* InviteUsersConfirmationSheetView.swift in Sources */,
 				C4D2BCAA54E2C62B94B24AF4 /* InviteUsersScreen.swift in Sources */,
 				E27C4D1A1F8BB77CA790B403 /* InviteUsersScreenCoordinator.swift in Sources */,
 				C26DB49C06C00B5DF1A991A5 /* InviteUsersScreenModels.swift in Sources */,
@@ -9022,6 +9029,7 @@
 				7E91BAC17963ED41208F489B /* UserSessionStore.swift in Sources */,
 				79D57E9AE03A2DC689D14EA2 /* UserSessionStoreMock.swift in Sources */,
 				AC69B6DF15FC451AB2945036 /* UserSessionStoreProtocol.swift in Sources */,
+				9707AF8D41667FA9B35E8953 /* UserToInvite.swift in Sources */,
 				2447FADEF13225BB6227B977 /* VerificationBadge.swift in Sources */,
 				5C33976A720B64094CBC56B1 /* VideoMediaEventsTimelineView.swift in Sources */,
 				F07D88421A9BC4D03D4A5055 /* VideoRoomTimelineItem.swift in Sources */,

ElementX/Resources/Localizations/en.lproj/Untranslated.strings

@@ -1,3 +1,7 @@
+"crypto_history_sharing_confirm_invite_dialog_content" = "You currently don’t have any chats with these contacts. Confirm inviting them to this room before continuing.";
+"crypto_history_sharing_confirm_invite_dialog_title" = "Invite new contacts to this room?";
+"crypto_history_sharing_confirm_start_chat_dialog_content" = "You currently don’t have any chats with this person. Confirm inviting them before continuing.";
+"crypto_history_sharing_confirm_start_chat_dialog_title" = "Start a chat with this new contact?";
 "soft_logout_clear_data_dialog_content" = "Clear all data currently stored on this device?\nSign in again to access your account data and messages.";
 "soft_logout_clear_data_dialog_title" = "Clear data";
 "soft_logout_clear_data_notice" = "Warning: Your personal data (including encryption keys) is still stored on this device.\n\nClear it if you’re finished using this device, or want to sign in to another account.";

ElementX/Sources/FlowCoordinators/ChatsTabFlowCoordinator.swift

@@ -791,7 +791,8 @@ class ChatsTabFlowCoordinator: FlowCoordinatorProtocol {
                                                                 isPresentedModally: true,
                                                                 userSession: userSession,
                                                                 userIndicatorController: flowParameters.userIndicatorController,
-                                                                analytics: flowParameters.analytics)
+                                                                analytics: flowParameters.analytics,
+                                                                appSettings: flowParameters.appSettings)
         let coordinator = UserProfileScreenCoordinator(parameters: parameters)
         coordinator.actionsPublisher.sink { [weak self] action in
             guard let self else { return }

ElementX/Sources/FlowCoordinators/RoomMembersFlowCoordinator.swift

@@ -225,7 +225,8 @@ final class RoomMembersFlowCoordinator: FlowCoordinatorProtocol {
                                                                   roomProxy: roomProxy,
                                                                   userSession: flowParameters.userSession,
                                                                   userIndicatorController: flowParameters.userIndicatorController,
-                                                                  analytics: flowParameters.analytics)
+                                                                  analytics: flowParameters.analytics,
+                                                                  appSettings: flowParameters.appSettings)
         let coordinator = RoomMemberDetailsScreenCoordinator(parameters: params)
         
         coordinator.actions.sink { [weak self] action in
@@ -286,7 +287,8 @@ final class RoomMembersFlowCoordinator: FlowCoordinatorProtocol {
                                                                 isPresentedModally: false,
                                                                 userSession: flowParameters.userSession,
                                                                 userIndicatorController: flowParameters.userIndicatorController,
-                                                                analytics: flowParameters.analytics)
+                                                                analytics: flowParameters.analytics,
+                                                                appSettings: flowParameters.appSettings)
         let coordinator = UserProfileScreenCoordinator(parameters: parameters)
         coordinator.actionsPublisher.sink { [weak self] action in
             guard let self else { return }

ElementX/Sources/Generated/Strings+Untranslated.swift

@@ -10,6 +10,14 @@ import Foundation
 // swiftlint:disable explicit_type_interface function_parameter_count identifier_name line_length
 // swiftlint:disable nesting type_body_length type_name vertical_whitespace_opening_braces
 internal enum UntranslatedL10n {
+  /// You currently don’t have any chats with these contacts. Confirm inviting them to this room before continuing.
+  internal static var cryptoHistorySharingConfirmInviteDialogContent: String { return UntranslatedL10n.tr("Untranslated", "crypto_history_sharing_confirm_invite_dialog_content") }
+  /// Invite new contacts to this room?
+  internal static var cryptoHistorySharingConfirmInviteDialogTitle: String { return UntranslatedL10n.tr("Untranslated", "crypto_history_sharing_confirm_invite_dialog_title") }
+  /// You currently don’t have any chats with this person. Confirm inviting them before continuing.
+  internal static var cryptoHistorySharingConfirmStartChatDialogContent: String { return UntranslatedL10n.tr("Untranslated", "crypto_history_sharing_confirm_start_chat_dialog_content") }
+  /// Start a chat with this new contact?
+  internal static var cryptoHistorySharingConfirmStartChatDialogTitle: String { return UntranslatedL10n.tr("Untranslated", "crypto_history_sharing_confirm_start_chat_dialog_title") }
   /// Clear all data currently stored on this device?
   /// Sign in again to access your account data and messages.
   internal static var softLogoutClearDataDialogContent: String { return UntranslatedL10n.tr("Untranslated", "soft_logout_clear_data_dialog_content") }

ElementX/Sources/Other/TestablePreview/TestablePreviewsDictionary.swift

@@ -67,6 +67,7 @@ enum TestablePreviewsDictionary {
         "IdentityConfirmedScreen_Previews" : IdentityConfirmedScreen_Previews.self,
         "ImageMediaEventsTimelineView_Previews" : ImageMediaEventsTimelineView_Previews.self,
         "ImageRoomTimelineView_Previews" : ImageRoomTimelineView_Previews.self,
+        "InviteUsersConfirmationSheetView_Previews" : InviteUsersConfirmationSheetView_Previews.self,
         "InviteUsersScreenSelectedItem_Previews" : InviteUsersScreenSelectedItem_Previews.self,
         "InviteUsersScreen_Previews" : InviteUsersScreen_Previews.self,
         "JoinRoomByAddressView_Previews" : JoinRoomByAddressView_Previews.self,

ElementX/Sources/Screens/InviteUsersScreen/InviteUsersScreenModels.swift

@@ -30,6 +30,7 @@ struct InviteUsersScreenViewState: BindableState {
     
     var selectedUsers: [UserProfileProxy] = []
     var membershipState: [String: MembershipState] = .init()
+    var usersToConfirm: [UserProfileProxy] = []
     
     var isSearching = false
     
@@ -69,6 +70,9 @@ struct InviteUsersScreenViewStateBindings {
     var searchQuery = ""
     var selectedUsersPosition: String?
     
+    /// Whether we are showing the confirmation dialog.
+    var presentConfirmationDialog = false
+    
     /// Information describing the currently displayed alert.
     var alertInfo: AlertInfo<InviteUsersScreenErrorType>?
 }
@@ -76,5 +80,7 @@ struct InviteUsersScreenViewStateBindings {
 enum InviteUsersScreenViewAction {
     case cancel
     case proceed
+    case removeUnknownUsers
+    case confirmUnknownUsers
     case toggleUser(UserProfileProxy)
 }

ElementX/Sources/Screens/InviteUsersScreen/InviteUsersScreenViewModel.swift

@@ -13,6 +13,7 @@ import SwiftUI
 typealias InviteUsersScreenViewModelType = StateStoreViewModel<InviteUsersScreenViewState, InviteUsersScreenViewAction>
 
 class InviteUsersScreenViewModel: InviteUsersScreenViewModelType, InviteUsersScreenViewModelProtocol {
+    private let clientProxy: ClientProxyProtocol
     private let roomProxy: JoinedRoomProxyProtocol
     private let userDiscoveryService: UserDiscoveryServiceProtocol
     private let userIndicatorController: UserIndicatorControllerProtocol
@@ -31,6 +32,7 @@ class InviteUsersScreenViewModel: InviteUsersScreenViewModelType, InviteUsersScr
          userDiscoveryService: UserDiscoveryServiceProtocol,
          userIndicatorController: UserIndicatorControllerProtocol,
          appSettings: AppSettings) {
+        clientProxy = userSession.clientProxy
         self.roomProxy = roomProxy
         self.userDiscoveryService = userDiscoveryService
         self.userIndicatorController = userIndicatorController
@@ -59,6 +61,23 @@ class InviteUsersScreenViewModel: InviteUsersScreenViewModelType, InviteUsersScr
         case .cancel:
             actionsSubject.send(.dismiss)
         case .proceed:
+            guard appSettings.enableKeyShareOnInvite,
+                  roomProxy.details.historySharingState != RoomHistorySharingState.hidden,
+                  !state.usersToConfirm.isEmpty,
+                  !state.isSkippable else {
+                inviteUsers(state.selectedUsers.map(\.userID), roomProxy: roomProxy)
+                return
+            }
+            state.bindings.presentConfirmationDialog = true
+        case .removeUnknownUsers:
+            state.bindings.presentConfirmationDialog = false
+            state.selectedUsers.removeAll { user in
+                state.usersToConfirm.contains { $0.userID == user.userID }
+            }
+            state.usersToConfirm = []
+        case .confirmUnknownUsers:
+            state.bindings.presentConfirmationDialog = false
+            state.usersToConfirm = []
             inviteUsers(state.selectedUsers.map(\.userID), roomProxy: roomProxy)
         case .toggleUser(let user):
             toggleUser(user)
@@ -73,6 +92,17 @@ class InviteUsersScreenViewModel: InviteUsersScreenViewModelType, InviteUsersScr
         } else {
             state.selectedUsers.append(user)
             withElementAnimation(.easeInOut) { state.bindings.selectedUsersPosition = user.userID }
+            Task {
+                let identityUnknown = if case .success(let identity) = await self.clientProxy.userIdentity(for: user.userID, fallBackToServer: false) {
+                    identity == nil
+                } else {
+                    true
+                }
+                if identityUnknown {
+                    // If we do not have the identity cached, we will prompt the user to confirm they meant to invite them.
+                    self.state.usersToConfirm.append(user)
+                }
+            }
         }
     }
     

ElementX/Sources/Screens/InviteUsersScreen/View/InviteUsersConfirmationSheetView.swift

@@ -0,0 +1,74 @@
+//
+// Copyright 2026 Element Creations Ltd.
+//
+// SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-Element-Commercial.
+// Please see LICENSE files in the repository root for full details.
+//
+
+import Compound
+import SwiftUI
+
+struct InviteUsersConfirmationSheetView: View {
+    @ObservedObject var context: InviteUsersScreenViewModel.Context
+    
+    /// The users whose identities we wish the user to confirm.
+    var users: [UserProfileProxy]
+    
+    var body: some View {
+        FullscreenDialog(topPadding: 24, horizontalPadding: 24) {
+            VStack(spacing: 32) {
+                TitleAndIcon(title: L10n.screenInviteUsersConfirmDialogTitle(users.count),
+                             subtitle: L10n.screenInviteUsersConfirmDialogSubtitle(users.count),
+                             icon: \.userAddSolid,
+                             iconStyle: .defaultSolid)
+                VStack(spacing: 0) {
+                    ForEach(users, id: \.userID) { user in
+                        UserProfileListRow(user: user,
+                                           membership: nil,
+                                           mediaProvider: context.mediaProvider,
+                                           kind: .label)
+                            .rowDivider(alignment: .top)
+                            .accessibilityIdentifier(A11yIdentifiers.inviteUsersScreen.userProfile)
+                    }
+                }
+            }
+        } bottomContent: {
+            HStack(spacing: 32) {
+                Button(L10n.actionRemove, role: .cancel) {
+                    context.send(viewAction: .removeUnknownUsers)
+                }
+                .buttonStyle(.compound(.secondary))
+                
+                Button(L10n.actionInvite) {
+                    context.send(viewAction: .confirmUnknownUsers)
+                }
+                .buttonStyle(.compound(.primary))
+            }
+        }
+        .background()
+        .backgroundStyle(.compound.bgCanvasDefault)
+        .interactiveDismissDisabled()
+    }
+}
+
+struct InviteUsersConfirmationSheetView_Previews: PreviewProvider, TestablePreview {
+    static var viewModel = makeViewModel()
+    
+    static var previews: some View {
+        InviteUsersConfirmationSheetView(context: viewModel.context, users: [.mockAlice, .mockCharlie, .mockBob, .mockDan])
+            .previewDisplayName("Default")
+    }
+    
+    static func makeViewModel() -> InviteUsersScreenViewModel {
+        let viewModel = InviteUsersScreenViewModel(userSession: UserSessionMock(.init(clientProxy: ClientProxyMock(.init()))),
+                                                   roomProxy: JoinedRoomProxyMock(.init(members: [])),
+                                                   isSkippable: true,
+                                                   userDiscoveryService: UserDiscoveryServiceMock(),
+                                                   userIndicatorController: UserIndicatorControllerMock(),
+                                                   appSettings: ServiceLocator.shared.settings)
+        
+        viewModel.state.usersToConfirm = [.mockAlice, .mockCharlie, .mockBob, .mockDan]
+        
+        return viewModel
+    }
+}

ElementX/Sources/Screens/InviteUsersScreen/View/InviteUsersScreen.swift

@@ -31,6 +31,9 @@ struct InviteUsersScreen: View {
                               disablesInteractiveDismiss: true,
                               accessibilityFocusOnStart: true)
             .compoundSearchField()
+            .sheet(isPresented: $context.presentConfirmationDialog) {
+                InviteUsersConfirmationSheetView(context: context, users: context.viewState.usersToConfirm)
+            }
             .alert(item: $context.alertInfo)
             .navigationBarBackButtonHidden(context.viewState.isSkippable)
     }
@@ -149,6 +152,7 @@ struct InviteUsersScreen_Previews: PreviewProvider, TestablePreview {
     static let viewModel = makeViewModel()
     static let searchingViewModel = makeViewModel(searchQuery: "Alice")
     static let selectedViewModel = makeViewModel(hasSelection: true)
+    static let confirmSelectedViewModel = makeViewModel(shouldConfirm: true)
     
     static var previews: some View {
         ElementNavigationStack {
@@ -170,9 +174,14 @@ struct InviteUsersScreen_Previews: PreviewProvider, TestablePreview {
         }
         .previewDisplayName("Selected")
         .snapshotPreferences(expect: selectedViewModel.context.$viewState.map { !$0.selectedUsers.isEmpty })
+        
+        ElementNavigationStack {
+            InviteUsersScreen(context: confirmSelectedViewModel.context)
+        }
+        .previewDisplayName("Confirm Selected")
     }
     
-    static func makeViewModel(searchQuery: String? = nil, hasSelection: Bool = false) -> InviteUsersScreenViewModel {
+    static func makeViewModel(searchQuery: String? = nil, hasSelection: Bool = false, shouldConfirm: Bool = false) -> InviteUsersScreenViewModel {
         let clientProxy = ClientProxyMock(.init())
         clientProxy.recentConversationCounterpartsReturnValue = [.mockAlice, .mockBob, .mockCharlie, .mockDan, .mockVerbose]
         
@@ -194,6 +203,11 @@ struct InviteUsersScreen_Previews: PreviewProvider, TestablePreview {
             viewModel.state.selectedUsers = [.mockAlice]
         }
         
+        if shouldConfirm {
+            viewModel.state.usersToConfirm = [.mockAlice, .mockAlice, .mockAlice, .mockAlice, .mockAlice, .mockAlice, .mockAlice, .mockAlice, .mockAlice]
+            viewModel.state.bindings.presentConfirmationDialog = true
+        }
+        
         return viewModel
     }
 }

ElementX/Sources/Screens/RoomMemberDetailsScreen/RoomMemberDetailsScreenCoordinator.swift

@@ -15,6 +15,7 @@ struct RoomMemberDetailsScreenCoordinatorParameters {
     let userSession: UserSessionProtocol
     let userIndicatorController: UserIndicatorControllerProtocol
     let analytics: AnalyticsService
+    let appSettings: AppSettings
 }
 
 enum RoomMemberDetailsScreenCoordinatorAction {
@@ -39,7 +40,8 @@ final class RoomMemberDetailsScreenCoordinator: CoordinatorProtocol {
                                                      roomProxy: parameters.roomProxy,
                                                      userSession: parameters.userSession,
                                                      userIndicatorController: parameters.userIndicatorController,
-                                                     analytics: parameters.analytics)
+                                                     analytics: parameters.analytics,
+                                                     appSettings: parameters.appSettings)
     }
     
     func start() {

ElementX/Sources/Screens/RoomMemberDetailsScreen/RoomMemberDetailsScreenModels.swift

@@ -79,7 +79,7 @@ struct RoomMemberDetailsScreenViewStateBindings {
     
     var ignoreUserAlert: IgnoreUserAlertItem?
     var alertInfo: AlertInfo<RoomMemberDetailsScreenAlertType>?
-    var inviteConfirmationUser: UserProfileProxy?
+    var inviteConfirmationUser: UserToInvite?
     
     /// A media item that will be previewed with QuickLook.
     var mediaPreviewItem: MediaPreviewItem?

ElementX/Sources/Screens/RoomMemberDetailsScreen/RoomMemberDetailsScreenViewModel.swift

@@ -16,6 +16,7 @@ class RoomMemberDetailsScreenViewModel: RoomMemberDetailsScreenViewModelType, Ro
     private let userSession: UserSessionProtocol
     private let userIndicatorController: UserIndicatorControllerProtocol
     private let analytics: AnalyticsService
+    private let appSettings: AppSettings
     
     private var actionsSubject: PassthroughSubject<RoomMemberDetailsScreenViewModelAction, Never> = .init()
     
@@ -29,11 +30,13 @@ class RoomMemberDetailsScreenViewModel: RoomMemberDetailsScreenViewModelType, Ro
          roomProxy: JoinedRoomProxyProtocol,
          userSession: UserSessionProtocol,
          userIndicatorController: UserIndicatorControllerProtocol,
-         analytics: AnalyticsService) {
+         analytics: AnalyticsService,
+         appSettings: AppSettings) {
         self.roomProxy = roomProxy
         self.userSession = userSession
         self.userIndicatorController = userIndicatorController
         self.analytics = analytics
+        self.appSettings = appSettings
         
         let initialViewState = RoomMemberDetailsScreenViewState(userID: userID, bindings: .init())
         
@@ -197,8 +200,19 @@ class RoomMemberDetailsScreenViewModel: RoomMemberDetailsScreenViewModelType, Ro
         case .success(let roomID):
             if let roomID {
                 actionsSubject.send(.openDirectChat(roomID: roomID))
+            } else if appSettings.enableKeyShareOnInvite, roomProxy.details.historySharingState != RoomHistorySharingState.hidden {
+                Task {
+                    let identity = await self.userSession.clientProxy.userIdentity(for: roomMemberProxy.userID, fallBackToServer: false)
+                    let user: UserProfileProxy = .init(userID: roomMemberProxy.userID, displayName: roomMemberProxy.displayName, avatarURL: roomMemberProxy.avatarURL)
+                    let isUnknown = if case .success(let identity) = identity {
+                        identity == nil
+                    } else {
+                        true
+                    }
+                    self.state.bindings.inviteConfirmationUser = .init(user: user, isUnknown: isUnknown)
+                }
             } else {
-                state.bindings.inviteConfirmationUser = .init(userID: roomMemberProxy.userID, displayName: roomMemberProxy.displayName, avatarURL: roomMemberProxy.avatarURL)
+                state.bindings.inviteConfirmationUser = .init(user: .init(userID: roomMemberProxy.userID, displayName: roomMemberProxy.displayName, avatarURL: roomMemberProxy.avatarURL), isUnknown: false)
             }
         case .failure:
             state.bindings.alertInfo = .init(id: .failedOpeningDirectChat)

ElementX/Sources/Screens/RoomMemberDetailsScreen/View/RoomMemberDetailsScreen.swift

@@ -240,6 +240,7 @@ struct RoomMemberDetailsScreen_Previews: PreviewProvider, TestablePreview {
                                                 roomProxy: roomProxyMock,
                                                 userSession: UserSessionMock(.init(clientProxy: clientProxyMock)),
                                                 userIndicatorController: ServiceLocator.shared.userIndicatorController,
-                                                analytics: ServiceLocator.shared.analytics)
+                                                analytics: ServiceLocator.shared.analytics,
+                                                appSettings: ServiceLocator.shared.settings)
     }
 }

ElementX/Sources/Screens/StartChatScreen/StartChatScreenModels.swift

@@ -44,7 +44,7 @@ struct StartChatScreenViewStateBindings {
     /// Information describing the currently displayed alert.
     var alertInfo: AlertInfo<StartChatScreenErrorType>?
     
-    var selectedUserToInvite: UserProfileProxy?
+    var selectedUserToInvite: UserToInvite?
     var isJoinRoomByAddressSheetPresented = false
 }
 

ElementX/Sources/Screens/StartChatScreen/StartChatScreenViewModel.swift

@@ -67,8 +67,21 @@ class StartChatScreenViewModel: StartChatScreenViewModelType, StartChatScreenVie
                 hideLoadingIndicator()
                 actionsSubject.send(.showRoom(roomID: roomId))
             case .success:
-                hideLoadingIndicator()
+                if appSettings.enableKeyShareOnInvite {
-                state.bindings.selectedUserToInvite = user
+                    Task {
+                        // If an error occured while fetching the identity, assume they are unknown.
+                        let isUnknown = if case .success(let identity) = await self.userSession.clientProxy.userIdentity(for: user.userID, fallBackToServer: false) {
+                            identity == nil
+                        } else {
+                            true
+                        }
+                        self.state.bindings.selectedUserToInvite = UserToInvite(user: user, isUnknown: isUnknown)
+                        hideLoadingIndicator()
+                    }
+                } else {
+                    hideLoadingIndicator()
+                    state.bindings.selectedUserToInvite = UserToInvite(user: user, isUnknown: false)
+                }
             case .failure:
                 hideLoadingIndicator()
                 displayError()

ElementX/Sources/Screens/StartChatScreen/View/SendInviteConfirmationView.swift

@@ -10,7 +10,7 @@ import Compound
 import SwiftUI
 
 struct SendInviteConfirmationView: View {
-    let userToInvite: UserProfileProxy
+    let userToInvite: UserToInvite
     let mediaProvider: MediaProviderProtocol?
     let onInvite: () -> Void
     
@@ -19,14 +19,26 @@ struct SendInviteConfirmationView: View {
     @State private var sheetHeight: CGFloat = .zero
     private let topPadding: CGFloat = 24
     
+    private var title: String {
+        if userToInvite.isUnknown {
+            L10n.screenBottomSheetCreateDmUnknownUserTitle
+        } else {
+            L10n.screenBottomSheetCreateDmTitle
+        }
+    }
+    
     private var subtitle: String {
         let string: String
         if let displayName = userToInvite.displayName {
-            string = L10n.commonNameAndId(displayName, userToInvite.userID)
+            string = L10n.commonNameAndId(displayName, userToInvite.id)
         } else {
-            string = userToInvite.userID
+            string = userToInvite.id
+        }
+        return if userToInvite.isUnknown {
+            L10n.screenBottomSheetCreateDmUnknownUserContent
+        } else {
+            L10n.screenBottomSheetCreateDmMessage(string)
         }
-        return L10n.screenBottomSheetCreateDmMessage(string)
     }
     
     var body: some View {
@@ -48,11 +60,11 @@ struct SendInviteConfirmationView: View {
         VStack(spacing: 16) {
             LoadableAvatarImage(url: userToInvite.avatarURL,
                                 name: userToInvite.displayName,
-                                contentID: userToInvite.userID,
+                                contentID: userToInvite.id,
                                 avatarSize: .user(on: .sendInviteConfirmation),
                                 mediaProvider: mediaProvider)
             VStack(spacing: 8) {
-                Text(L10n.screenBottomSheetCreateDmTitle)
+                Text(title)
                     .multilineTextAlignment(.center)
                     .font(.compound.headingMDBold)
                     .foregroundStyle(.compound.textPrimary)
@@ -91,7 +103,22 @@ struct SendInviteConfirmationView: View {
 
 struct SendInviteConfirmationView_Previews: PreviewProvider, TestablePreview {
     static var previews: some View {
-        SendInviteConfirmationView(userToInvite: .mockBob,
+        SendInviteConfirmationView(userToInvite: .mockKnownBob,
                                    mediaProvider: nil) { }
+            .previewDisplayName("With Known Identity")
+        
+        SendInviteConfirmationView(userToInvite: .mockUnknownBob,
+                                   mediaProvider: nil) { }
+            .previewDisplayName("With Unknown Identity")
+    }
+}
+
+private extension UserToInvite {
+    static var mockKnownBob: Self {
+        .init(user: .mockBob, isUnknown: false)
+    }
+    
+    static var mockUnknownBob: Self {
+        .init(user: .mockBob, isUnknown: true)
     }
 }

ElementX/Sources/Screens/StartChatScreen/View/StartChatScreen.swift

@@ -32,9 +32,10 @@ struct StartChatScreen: View {
                           disablesInteractiveDismiss: true)
         .compoundSearchField()
         .alert(item: $context.alertInfo)
-        .sheet(item: $context.selectedUserToInvite) { user in
+        .sheet(item: $context.selectedUserToInvite) { userToInvite in
-            SendInviteConfirmationView(userToInvite: user, mediaProvider: context.mediaProvider) {
+            SendInviteConfirmationView(userToInvite: userToInvite,
-                context.send(viewAction: .createDM(user: user))
+                                       mediaProvider: context.mediaProvider) {
+                context.send(viewAction: .createDM(user: userToInvite.user))
             }
         }
         .sheet(isPresented: $context.isJoinRoomByAddressSheetPresented) {

ElementX/Sources/Screens/UserProfileScreen/UserProfileScreenCoordinator.swift

@@ -15,6 +15,7 @@ struct UserProfileScreenCoordinatorParameters {
     let userSession: UserSessionProtocol
     let userIndicatorController: UserIndicatorControllerProtocol
     let analytics: AnalyticsService
+    let appSettings: AppSettings
 }
 
 enum UserProfileScreenCoordinatorAction {
@@ -38,7 +39,8 @@ final class UserProfileScreenCoordinator: CoordinatorProtocol {
                                                isPresentedModally: parameters.isPresentedModally,
                                                userSession: parameters.userSession,
                                                userIndicatorController: parameters.userIndicatorController,
-                                               analytics: parameters.analytics)
+                                               analytics: parameters.analytics,
+                                               appSettings: parameters.appSettings)
     }
     
     func start() {

ElementX/Sources/Screens/UserProfileScreen/UserProfileScreenModels.swift

@@ -20,6 +20,7 @@ struct UserProfileScreenViewState: BindableState {
     let isPresentedModally: Bool
     
     var userProfile: UserProfileProxy?
+    var isIdentityKnown = false
     var isVerified: Bool?
     var permalink: URL?
     var dmRoomID: String?
@@ -33,7 +34,7 @@ struct UserProfileScreenViewState: BindableState {
 
 struct UserProfileScreenViewStateBindings {
     var alertInfo: AlertInfo<UserProfileScreenAlertType>?
-    var inviteConfirmationUser: UserProfileProxy?
+    var inviteConfirmationUser: UserToInvite?
     
     /// A media item that will be previewed with QuickLook.
     var mediaPreviewItem: MediaPreviewItem?

ElementX/Sources/Screens/UserProfileScreen/UserProfileScreenViewModel.swift

@@ -16,6 +16,7 @@ class UserProfileScreenViewModel: UserProfileScreenViewModelType, UserProfileScr
     private let userSession: UserSessionProtocol
     private let userIndicatorController: UserIndicatorControllerProtocol
     private let analytics: AnalyticsService
+    private let appSettings: AppSettings
     
     private var actionsSubject: PassthroughSubject<UserProfileScreenViewModelAction, Never> = .init()
     var actionsPublisher: AnyPublisher<UserProfileScreenViewModelAction, Never> {
@@ -26,10 +27,12 @@ class UserProfileScreenViewModel: UserProfileScreenViewModelType, UserProfileScr
          isPresentedModally: Bool,
          userSession: UserSessionProtocol,
          userIndicatorController: UserIndicatorControllerProtocol,
-         analytics: AnalyticsService) {
+         analytics: AnalyticsService,
+         appSettings: AppSettings) {
         self.userSession = userSession
         self.userIndicatorController = userIndicatorController
         self.analytics = analytics
+        self.appSettings = appSettings
         
         let initialViewState = UserProfileScreenViewState(userID: userID,
                                                           isOwnUser: userID == userSession.clientProxy.userID,
@@ -92,8 +95,10 @@ class UserProfileScreenViewModel: UserProfileScreenViewModelType, UserProfileScr
         }
         
         if case let .success(.some(identity)) = await identityResult {
+            state.isIdentityKnown = true
             state.isVerified = identity.verificationState == .verified
         } else {
+            state.isIdentityKnown = false
             MXLog.error("Failed to find the user's identity.")
         }
     }
@@ -122,7 +127,18 @@ class UserProfileScreenViewModel: UserProfileScreenViewModelType, UserProfileScr
             if let roomID {
                 actionsSubject.send(.openDirectChat(roomID: roomID))
             } else {
-                state.bindings.inviteConfirmationUser = userProfile
+                if appSettings.enableKeyShareOnInvite {
+                    Task {
+                        let isUnknown = if case let .success(identity) = await userSession.clientProxy.userIdentity(for: userProfile.userID, fallBackToServer: false) {
+                            identity == nil
+                        } else {
+                            true
+                        }
+                        state.bindings.inviteConfirmationUser = .init(user: userProfile, isUnknown: isUnknown)
+                    }
+                } else {
+                    state.bindings.inviteConfirmationUser = .init(user: userProfile, isUnknown: false)
+                }
             }
         case .failure:
             state.bindings.alertInfo = .init(id: .failedOpeningDirectChat)

ElementX/Sources/Screens/UserProfileScreen/View/UserProfileScreen.swift

@@ -21,8 +21,8 @@ struct UserProfileScreen: View {
         .navigationBarTitleDisplayMode(.inline)
         .toolbar { toolbar }
         .alert(item: $context.alertInfo)
-        .sheet(item: $context.inviteConfirmationUser) { user in
+        .sheet(item: $context.inviteConfirmationUser) { userToInvite in
-            SendInviteConfirmationView(userToInvite: user,
+            SendInviteConfirmationView(userToInvite: userToInvite,
                                        mediaProvider: context.mediaProvider) {
                 context.send(viewAction: .createDirectChat)
             }
@@ -147,6 +147,7 @@ struct UserProfileScreen_Previews: PreviewProvider, TestablePreview {
                                           isPresentedModally: false,
                                           userSession: UserSessionMock(.init(clientProxy: clientProxyMock)),
                                           userIndicatorController: ServiceLocator.shared.userIndicatorController,
-                                          analytics: ServiceLocator.shared.analytics)
+                                          analytics: ServiceLocator.shared.analytics,
+                                          appSettings: ServiceLocator.shared.settings)
     }
 }

ElementX/Sources/Services/Room/UserToInvite.swift

@@ -0,0 +1,31 @@
+//
+// Copyright 2026 Element Creations Ltd.
+//
+// SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-Element-Commercial.
+// Please see LICENSE files in the repository root for full details.
+//
+
+import Foundation
+
+struct UserToInvite: Identifiable {
+    /// The profile of the user being invited.
+    var user: UserProfileProxy
+    
+    /// The ID of the user being invited.
+    var id: String {
+        user.id
+    }
+    
+    /// Whether we have the cryptographic identity of this user cached locally.
+    var isUnknown: Bool
+    
+    /// The display name of the user being invited
+    var displayName: String? {
+        user.displayName
+    }
+    
+    /// The avatar URL of the user's profile, if available.
+    var avatarURL: URL? {
+        user.avatarURL
+    }
+}

PreviewTests/Sources/GeneratedPreviewTests.swift

@@ -475,6 +475,14 @@ extension PreviewTests {
         }
     }
 
+    @Test
+    func inviteUsersConfirmationSheetView() async throws {
+        AppSettings.resetAllSettings() // Ensure this test's previews start with fresh settings.
+        for (index, preview) in InviteUsersConfirmationSheetView_Previews._allPreviews.enumerated() {
+            try await assertSnapshots(matching: preview, step: index)
+        }
+    }
+
     @Test
     func inviteUsersScreenSelectedItem() async throws {
         AppSettings.resetAllSettings() // Ensure this test's previews start with fresh settings.

PreviewTests/Sources/__Snapshots__/PreviewTests/inviteUsersConfirmationSheetView.Default-iPad-en-GB.png

@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:b1f7bbc91732d5bc2846a22b9c992705ba023ace7c89f038e69211010bf2830f
+size 155722

PreviewTests/Sources/__Snapshots__/PreviewTests/inviteUsersConfirmationSheetView.Default-iPad-pseudo.png

@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:1d873a384efccce301a79b01f5d549c39724a2b7798315ab0334eeaf2d73f947
+size 144978

PreviewTests/Sources/__Snapshots__/PreviewTests/inviteUsersConfirmationSheetView.Default-iPhone-en-GB.png

@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:58cfabb92619e5d5f716d5299975ca4f2a5a38ba578a241c1fa29ef226e36a42
+size 103461

PreviewTests/Sources/__Snapshots__/PreviewTests/inviteUsersConfirmationSheetView.Default-iPhone-pseudo.png

@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:0f219f191ab96ba0dc142114ea796a0fb0f9af30cc2ce8f29b99b0bb6718d7c3
+size 96500

PreviewTests/Sources/__Snapshots__/PreviewTests/inviteUsersScreen.Confirm-Selected-iPad-en-GB.png

@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:2b96b85d9a091da9515212b02ecdac23b23f2f4c9e5a1ee8e9bc68378a796cb3
+size 152293

PreviewTests/Sources/__Snapshots__/PreviewTests/inviteUsersScreen.Confirm-Selected-iPad-pseudo.png

@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:117598d6b54d6bd68492fd14f091ff3a436ec920d4e8ac62f83ebb899a66a334
+size 156696

PreviewTests/Sources/__Snapshots__/PreviewTests/inviteUsersScreen.Confirm-Selected-iPhone-en-GB.png

@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:62680a39445805013d14963a26abfd65d192b96fedb321f5052c53e771575e0e
+size 96073

PreviewTests/Sources/__Snapshots__/PreviewTests/inviteUsersScreen.Confirm-Selected-iPhone-pseudo.png

@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:507a257e16587137397a716f62f466d934416f1349b1f39de213c5e59b947beb
+size 98954

PreviewTests/Sources/__Snapshots__/PreviewTests/sendInviteConfirmationView.With-Unknown-Identity-iPad-en-GB.png

@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:1fa0aca5dc6c594440ac0992afb83cad577f002abc84b63aa753d0b5e0e4f78d
+size 103351

PreviewTests/Sources/__Snapshots__/PreviewTests/sendInviteConfirmationView.With-Unknown-Identity-iPad-pseudo.png

@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:26fac79b2439a30f6f4a3850e2105a7b396c82b63bac87c7147e0de85210844e
+size 116096

PreviewTests/Sources/__Snapshots__/PreviewTests/sendInviteConfirmationView.With-Unknown-Identity-iPhone-en-GB.png

@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:b8235d8f2ce0f4f1187534209d3ab6ff7a21dcbd49f62b6ac2b8e6d19984c9af
+size 61539

PreviewTests/Sources/__Snapshots__/PreviewTests/sendInviteConfirmationView.With-Unknown-Identity-iPhone-pseudo.png

@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:9deea49513c330d3605f484f16b87e525dc49ec9892980be73740ca14d69305f
+size 84901

UnitTests/Sources/InviteUsersViewModelTests.swift

@@ -11,16 +11,28 @@ import Combine
 import Testing
 
 @MainActor
-struct InviteUsersScreenViewModelTests {
+final class InviteUsersScreenViewModelTests {
     var viewModel: InviteUsersScreenViewModelProtocol!
     var userDiscoveryService: UserDiscoveryServiceMock!
+    var clientProxy: ClientProxyMock!
+    var appSettings: AppSettings!
+
+    init() {
+        AppSettings.resetAllSettings()
+        appSettings = AppSettings()
+        ServiceLocator.shared.register(appSettings: appSettings)
+    }
+    
+    deinit {
+        AppSettings.resetAllSettings()
+    }
     
     var context: InviteUsersScreenViewModel.Context {
         viewModel.context
     }
     
     @Test
-    mutating func selectUser() {
+    func selectUser() {
         let roomProxy = JoinedRoomProxyMock(.init(name: "newroom", members: []))
         roomProxy.inviteUserIDReturnValue = .success(())
         setupViewModel(roomProxy: roomProxy, isSkippable: true)
@@ -32,7 +44,7 @@ struct InviteUsersScreenViewModelTests {
     }
     
     @Test
-    mutating func reselectUser() {
+    func reselectUser() {
         let roomProxy = JoinedRoomProxyMock(.init(name: "newroom", members: []))
         roomProxy.inviteUserIDReturnValue = .success(())
         setupViewModel(roomProxy: roomProxy, isSkippable: true)
@@ -46,7 +58,7 @@ struct InviteUsersScreenViewModelTests {
     }
     
     @Test
-    mutating func deselectUser() {
+    func deselectUser() {
         let roomProxy = JoinedRoomProxyMock(.init(name: "newroom", members: []))
         roomProxy.inviteUserIDReturnValue = .success(())
         setupViewModel(roomProxy: roomProxy, isSkippable: true)
@@ -60,7 +72,7 @@ struct InviteUsersScreenViewModelTests {
     }
     
     @Test
-    mutating func inviteButton() async throws {
+    func inviteButton() async throws {
         let mockedMembers: [RoomMemberProxyMock] = [.mockAlice, .mockBob]
         let roomProxy = JoinedRoomProxyMock(.init(name: "test", members: mockedMembers))
         roomProxy.inviteUserIDReturnValue = .success(())
@@ -87,10 +99,82 @@ struct InviteUsersScreenViewModelTests {
         #expect(roomProxy.inviteUserIDReceivedInvocations == [RoomMemberProxyMock.mockAlice.userID])
     }
     
-    private mutating func setupViewModel(roomProxy: JoinedRoomProxyProtocol, isSkippable: Bool) {
+    // MARK: - History Sharing
+    
+    @Test
+    func invitingUnknownUsersOpensConfirmationDialog() async throws {
+        appSettings.enableKeyShareOnInvite = true
+        
+        let mockedMembers: [RoomMemberProxyMock] = [.mockAlice, .mockBob]
+        let roomProxy = JoinedRoomProxyMock(.init(name: "test", members: mockedMembers))
+        roomProxy.inviteUserIDReturnValue = .success(())
+        setupViewModel(roomProxy: roomProxy, isSkippable: false)
+        
+        // Mock the lack of cached user identity
+        clientProxy.userIdentityForFallBackToServerReturnValue = .success(nil)
+        
+        let deferredState = deferFulfillment(viewModel.context.$viewState) { state in
+            state.isUserSelected(.mockAlice) && state.usersToConfirm.contains(.mockAlice)
+        }
+        
+        context.send(viewAction: .toggleUser(.mockAlice))
+        try await deferredState.fulfill()
+
+        context.send(viewAction: .proceed)
+        #expect(context.presentConfirmationDialog)
+        
+        let deferredAction = deferFulfillment(viewModel.actions) { action in
+            switch action {
+            case .dismiss:
+                return true
+            }
+        }
+        
+        context.send(viewAction: .confirmUnknownUsers)
+        
+        try await deferredAction.fulfill()
+        #expect(roomProxy.inviteUserIDReceivedInvocations == [RoomMemberProxyMock.mockAlice.userID])
+    }
+    
+    @Test
+    func removeButtonRemovesUnknownUsers() async throws {
+        appSettings.enableKeyShareOnInvite = true
+        
+        let mockedMembers: [RoomMemberProxyMock] = [.mockAlice, .mockBob]
+        let roomProxy = JoinedRoomProxyMock(.init(name: "test", members: mockedMembers))
+        roomProxy.inviteUserIDReturnValue = .success(())
+        setupViewModel(roomProxy: roomProxy, isSkippable: false)
+        
+        // Mock the lack of cached user identity
+        clientProxy.userIdentityForFallBackToServerReturnValue = .success(nil)
+        
+        var deferredState = deferFulfillment(viewModel.context.$viewState) { state in
+            state.isUserSelected(.mockAlice) && state.usersToConfirm.contains(.mockAlice)
+        }
+        
+        context.send(viewAction: .toggleUser(.mockAlice))
+        try await deferredState.fulfill()
+        
+        context.send(viewAction: .proceed)
+        #expect(context.presentConfirmationDialog)
+        
+        deferredState = deferFulfillment(viewModel.context.$viewState) { state in
+            !state.usersToConfirm.contains(.mockAlice) && !state.selectedUsers.contains(.mockAlice)
+        }
+        
+        context.send(viewAction: .removeUnknownUsers)
+        try await deferredState.fulfill()
+    }
+    
+    // MARK: - Helpers
+    
+    private func setupViewModel(roomProxy: JoinedRoomProxyProtocol, isSkippable: Bool) {
         userDiscoveryService = UserDiscoveryServiceMock()
         userDiscoveryService.searchProfilesWithReturnValue = .success([])
-        let viewModel = InviteUsersScreenViewModel(userSession: UserSessionMock(.init()),
+        
+        clientProxy = ClientProxyMock(.init(userID: "@mock:client.com"))
+        
+        let viewModel = InviteUsersScreenViewModel(userSession: UserSessionMock(.init(clientProxy: clientProxy)),
                                                    roomProxy: roomProxy,
                                                    isSkippable: isSkippable,
                                                    userDiscoveryService: userDiscoveryService,

UnitTests/Sources/RoomMemberDetailsViewModelTests.swift

@@ -11,6 +11,7 @@ import Testing
 
 @MainActor
 struct RoomMemberDetailsViewModelTests {
+    var clientProxy: ClientProxy!
     var viewModel: RoomMemberDetailsScreenViewModelProtocol!
     var roomProxyMock: JoinedRoomProxyMock!
     var roomMemberProxyMock: RoomMemberProxyMock!
@@ -151,6 +152,52 @@ struct RoomMemberDetailsViewModelTests {
         #expect(context.ignoreUserAlert == nil)
         #expect(context.alertInfo == nil)
     }
+    
+    // MARK: - History Sharing
+
+    @Test
+    mutating func inviteConfirmationFetchesIdentity() async throws {
+        let clientProxy = ClientProxyMock(.init())
+        setup(roomMemberProxyMock: .mockBob, clientProxy: clientProxy)
+        
+        let waitForMemberToLoad = deferFulfillment(context.$viewState) { $0.memberDetails != nil }
+        try await waitForMemberToLoad.fulfill()
+        
+        ServiceLocator.shared.settings.enableKeyShareOnInvite = true
+        clientProxy.directRoomForUserIDReturnValue = .success(nil)
+        clientProxy.userIdentityForFallBackToServerReturnValue = .success(UserIdentityProxyMock(configuration: .init(verificationState: .notVerified)))
+        
+        // The user identity becomes known, i.e. not unknown.
+        let deferred = deferFulfillment(viewModel.context.$viewState.compactMap(\.bindings.inviteConfirmationUser)) {
+            !$0.isUnknown
+        }
+        context.send(viewAction: .openDirectChat)
+        try await deferred.fulfill()
+        
+        #expect(clientProxy.userIdentityForFallBackToServerCalled)
+    }
+    
+    @Test
+    mutating func inviteConfirmationFallsBackToUnknownIdentityOnFailure() async throws {
+        let clientProxy = ClientProxyMock(.init())
+        setup(roomMemberProxyMock: .mockBob, clientProxy: clientProxy)
+        
+        let waitForMemberToLoad = deferFulfillment(context.$viewState) { $0.memberDetails != nil }
+        try await waitForMemberToLoad.fulfill()
+        
+        ServiceLocator.shared.settings.enableKeyShareOnInvite = true
+        clientProxy.directRoomForUserIDReturnValue = .success(nil)
+        clientProxy.userIdentityForFallBackToServerReturnValue = .failure(.forbiddenAccess)
+        
+        // The user identity is always unknown, i.e. never not unknown.
+        let deferred = deferFailure(viewModel.context.$viewState.compactMap(\.bindings.inviteConfirmationUser), timeout: .seconds(5)) {
+            !$0.isUnknown
+        }
+        context.send(viewAction: .openDirectChat)
+        try await deferred.fulfill()
+        
+        #expect(clientProxy.userIdentityForFallBackToServerCalled)
+    }
 
     // MARK: - Helpers
 
@@ -166,6 +213,7 @@ struct RoomMemberDetailsViewModelTests {
                                                      roomProxy: roomProxyMock,
                                                      userSession: userSession,
                                                      userIndicatorController: ServiceLocator.shared.userIndicatorController,
-                                                     analytics: ServiceLocator.shared.analytics)
+                                                     analytics: ServiceLocator.shared.analytics,
+                                                     appSettings: ServiceLocator.shared.settings)
     }
 }

UnitTests/Sources/StartChatViewModelTests.swift

@@ -85,6 +85,40 @@ struct StartChatScreenViewModelTests {
         try await deferred.fulfill()
     }
     
+    // MARK: - History Sharing
+    
+    @Test
+    func inviteConfirmationFetchesIdentity() async throws {
+        ServiceLocator.shared.settings.enableKeyShareOnInvite = true
+        clientProxy.directRoomForUserIDReturnValue = .success(nil)
+        clientProxy.userIdentityForFallBackToServerReturnValue = .success(UserIdentityProxyMock(configuration: .init(verificationState: .notVerified)))
+        
+        // User identity becomes known, i.e. not unknown
+        let deferred = deferFulfillment(viewModel.context.$viewState.compactMap(\.bindings.selectedUserToInvite)) {
+            !$0.isUnknown
+        }
+        context.send(viewAction: .selectUser(.mockBob))
+        try await deferred.fulfill()
+        
+        #expect(clientProxy.userIdentityForFallBackToServerCalled)
+    }
+    
+    @Test
+    func inviteConfirmationFallsBackToUnknownIdentityOnFailure() async throws {
+        ServiceLocator.shared.settings.enableKeyShareOnInvite = true
+        clientProxy.directRoomForUserIDReturnValue = .success(nil)
+        clientProxy.userIdentityForFallBackToServerReturnValue = .failure(.forbiddenAccess)
+        
+        // User identity never becomes known, i.e. is never not unknown
+        let deferred = deferFailure(viewModel.context.$viewState.compactMap(\.bindings.selectedUserToInvite), timeout: .seconds(5)) {
+            !$0.isUnknown
+        }
+        context.send(viewAction: .selectUser(.mockBob))
+        try await deferred.fulfill()
+        
+        #expect(clientProxy.userIdentityForFallBackToServerCalled)
+    }
+    
     // MARK: - Private
     
     private func assertSearchResults(toBe count: Int) {

UnitTests/Sources/UserProfileScreenViewModelTests.swift

@@ -21,7 +21,8 @@ struct UserProfileScreenViewModelTests {
                                                    isPresentedModally: false,
                                                    userSession: UserSessionMock(.init(clientProxy: clientProxy)),
                                                    userIndicatorController: ServiceLocator.shared.userIndicatorController,
-                                                   analytics: ServiceLocator.shared.analytics)
+                                                   analytics: ServiceLocator.shared.analytics,
+                                                   appSettings: ServiceLocator.shared.settings)
         let context = viewModel.context
         
         let waitForMemberToLoad = deferFulfillment(context.observe(\.viewState.userProfile)) { $0 != nil }
@@ -42,7 +43,8 @@ struct UserProfileScreenViewModelTests {
                                                    isPresentedModally: false,
                                                    userSession: UserSessionMock(.init(clientProxy: clientProxy)),
                                                    userIndicatorController: ServiceLocator.shared.userIndicatorController,
-                                                   analytics: ServiceLocator.shared.analytics)
+                                                   analytics: ServiceLocator.shared.analytics,
+                                                   appSettings: ServiceLocator.shared.settings)
         let context = viewModel.context
         
         let waitForMemberToLoad = deferFulfillment(context.observe(\.viewState.userProfile)) { $0 != nil }
@@ -52,4 +54,32 @@ struct UserProfileScreenViewModelTests {
         #expect(context.viewState.userProfile == profile)
         #expect(context.viewState.permalink != nil)
     }
+    
+    @Test
+    func startingDmWithUnknownUserFetchesIdentity() async throws {
+        ServiceLocator.shared.settings.enableKeyShareOnInvite = true
+        
+        let profile = UserProfileProxy.mockAlice
+        
+        let clientProxy = ClientProxyMock(.init())
+        clientProxy.directRoomForUserIDReturnValue = .success(nil)
+        clientProxy.userIdentityForFallBackToServerReturnValue = .success(nil)
+        
+        let viewModel = UserProfileScreenViewModel(userID: profile.userID,
+                                                   isPresentedModally: false,
+                                                   userSession: UserSessionMock(.init(clientProxy: clientProxy)),
+                                                   userIndicatorController: ServiceLocator.shared.userIndicatorController,
+                                                   analytics: ServiceLocator.shared.analytics,
+                                                   appSettings: ServiceLocator.shared.settings)
+        
+        let context = viewModel.context
+        
+        let waitForMemberToLoad = deferFulfillment(context.observe(\.viewState.userProfile)) { $0 != nil }
+        try await waitForMemberToLoad.fulfill()
+        
+        let deferred = deferFulfillment(context.observe(\.viewState.bindings).compactMap(\.inviteConfirmationUser), timeout: .seconds(5)) { $0.isUnknown }
+
+        context.send(viewAction: .openDirectChat)
+        try await deferred.fulfill()
+    }
 }