Merge pull request #1057 from vector-im/device-verification-ui

Implement UI for device verification

src/domain/navigation/index.ts

@@ -34,6 +34,8 @@ export type SegmentType = {
     "details": true;
     "members": true;
     "member": string;
+    "device-verification": string | boolean;
+    "join-room": true;
 };
 
 export function createNavigation(): Navigation<SegmentType> {
@@ -51,7 +53,7 @@ function allowsChild(parent: Segment<SegmentType> | undefined, child: Segment<Se
             // allowed root segments
             return type === "login" || type === "session" || type === "sso" || type === "logout";
         case "session":
-            return type === "room" || type === "rooms" || type === "settings" || type === "create-room" || type === "join-room";
+            return type === "room" || type === "rooms" || type === "settings" || type === "create-room" || type === "join-room" || type === "device-verification";
         case "rooms":
             // downside of the approach: both of these will control which tile is selected
             return type === "room" || type === "empty-grid-tile";

src/domain/session/SessionViewModel.js

@@ -26,6 +26,7 @@ import {RoomGridViewModel} from "./RoomGridViewModel.js";
 import {SettingsViewModel} from "./settings/SettingsViewModel.js";
 import {CreateRoomViewModel} from "./CreateRoomViewModel.js";
 import {JoinRoomViewModel} from "./JoinRoomViewModel";
+import {DeviceVerificationViewModel} from "./verification/DeviceVerificationViewModel";
 import {ViewModel} from "../ViewModel";
 import {RoomViewModelObservable} from "./RoomViewModelObservable.js";
 import {RightPanelViewModel} from "./rightpanel/RightPanelViewModel.js";
@@ -48,6 +49,7 @@ export class SessionViewModel extends ViewModel {
         this._gridViewModel = null;
         this._createRoomViewModel = null;
         this._joinRoomViewModel = null;
+        this._verificationViewModel = null;
         this._toastCollectionViewModel = this.track(new ToastCollectionViewModel(this.childOptions({
             session: this._client.session,
         })));
@@ -95,6 +97,14 @@ export class SessionViewModel extends ViewModel {
         }));
         this._updateJoinRoom(joinRoom.get());
 
+        if (this.features.crossSigning) {
+            const verification = this.navigation.observe("device-verification");
+                this.track(verification.subscribe((txnId) => {
+                    this._updateVerification(txnId);
+                }));
+                this._updateVerification(verification.get());
+        }
+
         const lightbox = this.navigation.observe("lightbox");
         this.track(lightbox.subscribe(eventId => {
             this._updateLightbox(eventId);
@@ -143,7 +153,8 @@ export class SessionViewModel extends ViewModel {
             this._gridViewModel ||
             this._settingsViewModel ||
             this._createRoomViewModel ||
-            this._joinRoomViewModel
+            this._joinRoomViewModel ||
+            this._verificationViewModel
         );
     }
 
@@ -179,6 +190,10 @@ export class SessionViewModel extends ViewModel {
         return this._joinRoomViewModel;
     }
 
+    get verificationViewModel() {
+        return this._verificationViewModel;
+    }
+
     get toastCollectionViewModel() {
         return this._toastCollectionViewModel;
     }
@@ -327,6 +342,17 @@ export class SessionViewModel extends ViewModel {
         this.emitChange("activeMiddleViewModel");
     }
 
+    _updateVerification(txnId) {
+        if (this._verificationViewModel) {
+            this._verificationViewModel = this.disposeTracked(this._verificationViewModel);
+        }
+        if (txnId) {
+            const request = this._client.session.crossSigning.get()?.receivedSASVerifications.get(txnId);
+            this._verificationViewModel = this.track(new DeviceVerificationViewModel(this.childOptions({ session: this._client.session, request })));
+        }
+        this.emitChange("activeMiddleViewModel");
+    }
+
     _updateLightbox(eventId) {
         if (this._lightboxViewModel) {
             this._lightboxViewModel = this.disposeTracked(this._lightboxViewModel);

src/domain/session/settings/KeyBackupViewModel.ts

@@ -157,6 +157,10 @@ export class KeyBackupViewModel extends ViewModel<SegmentType, Options> {
         }
     }
 
+    navigateToVerification(): void {
+        this.navigation.push("device-verification", true);
+    }
+
     get backupWriteStatus(): BackupWriteStatus {
         const keyBackup = this._keyBackup;
         if (!keyBackup || keyBackup.version === undefined) {

src/domain/session/toast/ToastCollectionViewModel.ts

@@ -17,9 +17,11 @@ limitations under the License.
 import {ConcatList} from "../../../observable";
 import {ViewModel, Options as BaseOptions} from "../../ViewModel";
 import {CallToastCollectionViewModel} from "./calls/CallsToastCollectionViewModel";
+import {VerificationToastCollectionViewModel} from "./verification/VerificationToastCollectionViewModel";
 import type {Session} from "../../../matrix/Session.js";
 import type {SegmentType} from "../../navigation";
 import type {BaseToastNotificationViewModel} from "./BaseToastNotificationViewModel";
+import type {IToastCollection} from "./IToastCollection";
 
 type Options = {
     session: Session;
@@ -31,9 +33,16 @@ export class ToastCollectionViewModel extends ViewModel<SegmentType, Options> {
     constructor(options: Options) {
         super(options);
         const session = this.getOption("session");
-        const vms = [
+        const collectionVms: IToastCollection[] = [];
-            this.track(new CallToastCollectionViewModel(this.childOptions({ session }))),
+        if (this.features.calls) {
-        ].map(vm => vm.toastViewModels);
+            collectionVms.push(this.track(new CallToastCollectionViewModel(this.childOptions({ session }))));
-        this.toastViewModels = new ConcatList(...vms);
+        }
+        if (this.features.crossSigning) {
+            collectionVms.push(this.track(new VerificationToastCollectionViewModel(this.childOptions({ session }))));
+        }
+        const vms: IToastCollection["toastViewModels"][] = collectionVms.map(vm => vm.toastViewModels);
+        if (vms.length !== 0) {
+            this.toastViewModels = new ConcatList(...vms);
+        }
     }
 }

src/domain/session/toast/verification/VerificationToastCollectionViewModel.ts

@@ -0,0 +1,76 @@
+
+/*
+Copyright 2023 The Matrix.org Foundation C.I.C.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+import {VerificationToastNotificationViewModel} from "./VerificationToastNotificationViewModel";
+import {ObservableArray} from "../../../../observable";
+import {ViewModel, Options as BaseOptions} from "../../../ViewModel";
+import type {Session} from "../../../../matrix/Session.js";
+import type {SegmentType} from "../../../navigation";
+import type {IToastCollection} from "../IToastCollection";
+import type {SASRequest} from "../../../../matrix/verification/SAS/SASRequest";
+
+type Options = {
+    session: Session;
+} & BaseOptions;
+
+export class VerificationToastCollectionViewModel extends ViewModel<SegmentType, Options> implements IToastCollection {
+    public readonly toastViewModels: ObservableArray<VerificationToastNotificationViewModel> = new ObservableArray();
+
+    constructor(options: Options) {
+        super(options);
+        this.subscribeToSASRequests();
+    }
+
+    private async subscribeToSASRequests() {
+        await this.getOption("session").crossSigning.waitFor(v => !!v).promise; 
+        const crossSigning = this.getOption("session").crossSigning.get();
+        this.track(crossSigning.receivedSASVerifications.subscribe(this));
+    }
+
+
+    async onAdd(_, request: SASRequest) {
+        const dismiss = () => {
+            const idx = this.toastViewModels.array.findIndex(vm => vm.request.id === request.id);
+            if (idx !== -1) {
+                this.toastViewModels.remove(idx);
+            }
+        };
+        this.toastViewModels.append(
+            this.track(new VerificationToastNotificationViewModel(this.childOptions({ request, dismiss })))
+        );
+    }
+
+    onRemove(_, request: SASRequest) {
+        const idx = this.toastViewModels.array.findIndex(vm => vm.request.id === request.id);
+        if (idx !== -1) {
+            this.toastViewModels.remove(idx);
+        }
+    }
+
+    onUpdate(_, request: SASRequest) {
+        const idx = this.toastViewModels.array.findIndex(vm => vm.request.id === request.id);
+        if (idx !== -1) {
+            this.toastViewModels.update(idx, this.toastViewModels.at(idx)!);
+        }
+    }
+
+    onReset() {
+        for (let i = 0; i < this.toastViewModels.length; ++i) {
+            this.toastViewModels.remove(i);
+        }
+    }
+}

src/domain/session/toast/verification/VerificationToastNotificationViewModel.ts

@@ -0,0 +1,53 @@
+/*
+Copyright 2023 The Matrix.org Foundation C.I.C.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+import {BaseClassOptions, BaseToastNotificationViewModel} from ".././BaseToastNotificationViewModel";
+import {SegmentType} from "../../../navigation";
+import {SASRequest} from "../../../../matrix/verification/SAS/SASRequest";
+
+type Options<N extends MinimumNeededSegmentType = SegmentType> = {
+    request: SASRequest;
+} & BaseClassOptions<N>;
+
+type MinimumNeededSegmentType = {
+    "device-verification": string | boolean;
+};
+
+export class VerificationToastNotificationViewModel<N extends MinimumNeededSegmentType = SegmentType, O extends Options<N> = Options<N>> extends BaseToastNotificationViewModel<N, O> {
+    constructor(options: O) {
+        super(options);
+    }
+
+    get kind(): "verification" {
+        return "verification";
+    }
+
+    get request(): SASRequest {
+        return this.getOption("request");
+    }
+
+    get otherDeviceId(): string {
+        return this.request.deviceId;
+    }
+
+    accept() {
+        // @ts-ignore
+        this.navigation.push("device-verification", this.request.id);
+        this.dismiss();
+    }
+
+}
+
+

src/domain/session/verification/DeviceVerificationViewModel.ts

@@ -0,0 +1,96 @@
+/*
+Copyright 2023 The Matrix.org Foundation C.I.C.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+import {Options as BaseOptions} from "../../ViewModel";
+import {SegmentType} from "../../navigation/index";
+import {ErrorReportViewModel} from "../../ErrorReportViewModel";
+import {WaitingForOtherUserViewModel} from "./stages/WaitingForOtherUserViewModel";
+import {VerificationCancelledViewModel} from "./stages/VerificationCancelledViewModel";
+import {SelectMethodViewModel} from "./stages/SelectMethodViewModel";
+import {VerifyEmojisViewModel} from "./stages/VerifyEmojisViewModel";
+import {VerificationCompleteViewModel} from "./stages/VerificationCompleteViewModel";
+import type {Session} from "../../../matrix/Session.js";
+import type {SASVerification} from "../../../matrix/verification/SAS/SASVerification";
+import type {SASRequest} from "../../../matrix/verification/SAS/SASRequest";
+
+type Options = BaseOptions & {
+    session: Session;
+    request: SASRequest;
+};
+
+export class DeviceVerificationViewModel extends ErrorReportViewModel<SegmentType, Options> {
+    private sas: SASVerification;
+    private _currentStageViewModel: any;
+
+    constructor(options: Readonly<Options>) {
+        super(options);
+        const sasRequest = options.request;
+        if (options.request) {
+            this.start(sasRequest);
+        }
+        else {
+            // We are about to send the request
+            this.start(this.getOption("session").userId);
+        }
+    }
+
+    private async start(requestOrUserId: SASRequest | string) {
+        await this.logAndCatch("DeviceVerificationViewModel.start", (log) => {
+            const crossSigning = this.getOption("session").crossSigning.get();
+            this.sas = crossSigning.startVerification(requestOrUserId, log);
+            this.addEventListeners();
+            if (typeof requestOrUserId === "string") {
+                this.updateCurrentStageViewModel(new WaitingForOtherUserViewModel(this.childOptions({ sas: this.sas })));
+            }
+            return this.sas.start();
+        });
+    }
+    
+    private addEventListeners() {
+        this.track(this.sas.disposableOn("SelectVerificationStage", (stage) => {
+            this.updateCurrentStageViewModel(
+                new SelectMethodViewModel(this.childOptions({ sas: this.sas, stage: stage!, }))
+            );
+            }));
+        this.track(this.sas.disposableOn("EmojiGenerated", (stage) => {
+            this.updateCurrentStageViewModel(
+                new VerifyEmojisViewModel(this.childOptions({ stage: stage!, }))
+            );
+        }));
+        this.track(this.sas.disposableOn("VerificationCancelled", (cancellation) => {
+            this.updateCurrentStageViewModel(
+                new VerificationCancelledViewModel(
+                    this.childOptions({ cancellation: cancellation! })
+                )
+            );
+        }));
+        this.track(this.sas.disposableOn("VerificationCompleted", (deviceId) => {
+            this.updateCurrentStageViewModel(
+                new VerificationCompleteViewModel(this.childOptions({ deviceId: deviceId! }))
+            );
+        }));
+    }
+
+    private updateCurrentStageViewModel(vm) {
+        this._currentStageViewModel = this.disposeTracked(this._currentStageViewModel);
+        this._currentStageViewModel = this.track(vm);
+        this.emitChange("currentStageViewModel");
+    }
+
+    get currentStageViewModel() {
+        return this._currentStageViewModel;
+    }
+}

src/domain/session/verification/stages/SelectMethodViewModel.ts

@@ -0,0 +1,54 @@
+/*
+Copyright 2023 The Matrix.org Foundation C.I.C.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+import {SegmentType} from "../../../navigation/index";
+import {ErrorReportViewModel} from "../../../ErrorReportViewModel";
+import type {Options as BaseOptions} from "../../../ViewModel";
+import type {Session} from "../../../../matrix/Session.js";
+import type {SASVerification} from "../../../../matrix/verification/SAS/SASVerification";
+import type {SelectVerificationMethodStage} from "../../../../matrix/verification/SAS/stages/SelectVerificationMethodStage";
+
+type Options = BaseOptions & {
+    sas: SASVerification;
+    stage: SelectVerificationMethodStage;
+    session: Session;
+};
+
+export class SelectMethodViewModel extends ErrorReportViewModel<SegmentType, Options> {
+    public hasProceeded: boolean = false;
+
+    async proceed() {
+        await this.logAndCatch("SelectMethodViewModel.proceed", async (log) => {
+            await this.options.stage.selectEmojiMethod(log);
+            this.hasProceeded = true;
+            this.emitChange("hasProceeded");
+        });
+    }
+
+    async cancel() {
+        await this.logAndCatch("SelectMethodViewModel.cancel", async () => {
+            await this.options.sas.abort();
+        });
+    }
+
+    get deviceName() {
+        return this.options.stage.otherDeviceName;
+    }
+
+    get kind(): string {
+        return "select-method";
+    }
+}

src/domain/session/verification/stages/VerificationCancelledViewModel.ts

@@ -0,0 +1,42 @@
+/*
+Copyright 2023 The Matrix.org Foundation C.I.C.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+import {ViewModel, Options as BaseOptions} from "../../../ViewModel";
+import {SegmentType} from "../../../navigation/index";
+import type {CancelReason} from "../../../../matrix/verification/SAS/channel/types";
+import type {IChannel} from "../../../../matrix/verification/SAS/channel/Channel";
+
+type Options = BaseOptions & {
+    cancellation: IChannel["cancellation"];
+};
+
+export class VerificationCancelledViewModel extends ViewModel<SegmentType, Options> {
+    get cancelCode(): CancelReason {
+        return this.options.cancellation!.code;
+    }
+
+    get isCancelledByUs(): boolean {
+        return this.options.cancellation!.cancelledByUs;
+    }
+
+    gotoSettings() {
+        this.navigation.push("settings", true);
+    }
+
+    get kind(): string {
+        return "verification-cancelled";
+    }
+}

src/domain/session/verification/stages/VerificationCompleteViewModel.ts

@@ -0,0 +1,39 @@
+/*
+Copyright 2023 The Matrix.org Foundation C.I.C.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+import {SegmentType} from "../../../navigation/index";
+import {ErrorReportViewModel} from "../../../ErrorReportViewModel";
+import type {Options as BaseOptions} from "../../../ViewModel";
+import type {Session} from "../../../../matrix/Session.js";
+
+type Options = BaseOptions & {
+    deviceId: string;
+    session: Session;
+};
+
+export class VerificationCompleteViewModel extends ErrorReportViewModel<SegmentType, Options> {
+    get otherDeviceId(): string {
+        return this.options.deviceId;
+    }
+
+    gotoSettings() {
+        this.navigation.push("settings", true);
+    }
+
+    get kind(): string {
+        return "verification-completed";
+    }
+}

src/domain/session/verification/stages/VerifyEmojisViewModel.ts

@@ -0,0 +1,50 @@
+/*
+Copyright 2023 The Matrix.org Foundation C.I.C.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+import {SegmentType} from "../../../navigation/index";
+import {ErrorReportViewModel} from "../../../ErrorReportViewModel";
+import type {Options as BaseOptions} from "../../../ViewModel";
+import type {Session} from "../../../../matrix/Session.js";
+import type {CalculateSASStage} from "../../../../matrix/verification/SAS/stages/CalculateSASStage";
+
+type Options = BaseOptions & {
+    stage: CalculateSASStage;
+    session: Session;
+};
+
+export class VerifyEmojisViewModel extends ErrorReportViewModel<SegmentType, Options> {
+    private _isWaiting: boolean = false;
+
+    async setEmojiMatch(match: boolean) {
+        await this.logAndCatch("VerifyEmojisViewModel.setEmojiMatch", async () => {
+            await this.options.stage.setEmojiMatch(match);
+            this._isWaiting = true;
+            this.emitChange("isWaiting");
+        });
+    }
+
+    get emojis() {
+        return this.options.stage.emoji;
+    }
+
+    get kind(): string {
+        return "verify-emojis";
+    }
+
+    get isWaiting(): boolean {
+        return this._isWaiting;
+    }
+}

src/domain/session/verification/stages/WaitingForOtherUserViewModel.ts

@@ -0,0 +1,33 @@
+/*
+Copyright 2023 The Matrix.org Foundation C.I.C.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+import {ViewModel, Options as BaseOptions} from "../../../ViewModel";
+import {SegmentType} from "../../../navigation/index";
+import type {SASVerification} from "../../../../matrix/verification/SAS/SASVerification";
+
+type Options = BaseOptions & {
+    sas: SASVerification;
+};
+
+export class WaitingForOtherUserViewModel extends ViewModel<SegmentType, Options> {
+    async cancel() {
+        await this.options.sas.abort();
+    }
+
+    get kind(): string {
+        return "waiting-for-user";
+    }
+}

src/matrix/Session.js

@@ -365,9 +365,11 @@ export class Session {
                         olm: this._olm,
                         olmUtil: this._olmUtil,
                         deviceTracker: this._deviceTracker,
+                        deviceMessageHandler: this._deviceMessageHandler,
                         hsApi: this._hsApi,
                         ownUserId: this.userId,
-                        e2eeAccount: this._e2eeAccount
+                        e2eeAccount: this._e2eeAccount,
+                        deviceId: this.deviceId,
                     });
                     if (await crossSigning.load(log)) {
                         this._crossSigning.set(crossSigning);

src/matrix/verification/CrossSigning.ts

@@ -19,6 +19,8 @@ import {pkSign} from "./common";
 import {SASVerification} from "./SAS/SASVerification";
 import {ToDeviceChannel} from "./SAS/channel/Channel";
 import {VerificationEventType} from "./SAS/channel/types";
+import {ObservableMap} from "../../observable/map";
+import {SASRequest} from "./SAS/SASRequest";
 import type {SecretStorage} from "../ssss/SecretStorage";
 import type {Storage} from "../storage/idb/Storage";
 import type {Platform} from "../../platform/web/Platform";
@@ -29,6 +31,7 @@ import type {ILogItem} from "../../logging/types";
 import type {DeviceMessageHandler} from "../DeviceMessageHandler.js";
 import type {SignedValue, DeviceKey} from "../e2ee/common";
 import type * as OlmNamespace from "@matrix-org/olm";
+
 type Olm = typeof OlmNamespace;
 
 // we store cross-signing (and device) keys in the format we get them from the server
@@ -88,6 +91,7 @@ export class CrossSigning {
     private _isMasterKeyTrusted: boolean = false;
     private readonly deviceId: string;
     private sasVerificationInProgress?: SASVerification;
+    public receivedSASVerifications: ObservableMap<string, SASRequest> = new ObservableMap();
 
     constructor(options: {
         storage: Storage,
@@ -115,21 +119,7 @@ export class CrossSigning {
         this.deviceMessageHandler = options.deviceMessageHandler;
 
         this.deviceMessageHandler.on("message", async ({ unencrypted: unencryptedEvent }) => {
-            if (this.sasVerificationInProgress &&
+            this._handleSASDeviceMessage(unencryptedEvent);
-                (
-                    !this.sasVerificationInProgress.finished ||
-                    // If the start message is for the previous sasverification, ignore it.
-                    this.sasVerificationInProgress.channel.id === unencryptedEvent.content.transaction_id
-                )) {
-                return;
-            }
-            if (unencryptedEvent.type === VerificationEventType.Request ||
-                unencryptedEvent.type === VerificationEventType.Start) {
-                await this.platform.logger.run("Start verification from request", async (log) => {
-                    const sas = this.startVerification(unencryptedEvent.sender, unencryptedEvent, log);
-                    await sas?.start();
-                });
-            }
         })
     }
 
@@ -182,14 +172,18 @@ export class CrossSigning {
         return this._isMasterKeyTrusted;
     }
 
-    startVerification(userId: string, startingMessage: any, log: ILogItem): SASVerification | undefined {
+    startVerification(requestOrUserId: SASRequest, log: ILogItem): SASVerification | undefined;
+    startVerification(requestOrUserId: string, log: ILogItem): SASVerification | undefined;
+    startVerification(requestOrUserId: string | SASRequest, log: ILogItem): SASVerification | undefined {
         if (this.sasVerificationInProgress && !this.sasVerificationInProgress.finished) {
             return;
         }
+        const otherUserId = requestOrUserId instanceof SASRequest ? requestOrUserId.sender : requestOrUserId;
+        const startingMessage = requestOrUserId instanceof SASRequest ? requestOrUserId.startingMessage : undefined;
         const channel = new ToDeviceChannel({
             deviceTracker: this.deviceTracker,
             hsApi: this.hsApi,
-            otherUserId: userId,
+            otherUserId,
             clock: this.platform.clock,
             deviceMessageHandler: this.deviceMessageHandler,
             ourUserDeviceId: this.deviceId,
@@ -201,7 +195,7 @@ export class CrossSigning {
             olmUtil: this.olmUtil,
             ourUserId: this.ownUserId,
             ourUserDeviceId: this.deviceId,
-            otherUserId: userId,
+            otherUserId,
             log,
             channel,
             e2eeAccount: this.e2eeAccount,
@@ -212,6 +206,35 @@ export class CrossSigning {
         return this.sasVerificationInProgress;
     }
 
+    private _handleSASDeviceMessage(event: any) {
+        const txnId = event.content.transaction_id;
+        /**
+         * If we receive an event for the current/previously finished 
+         * SAS verification, we should ignore it because the device channel
+         * object (who also listens for to_device messages) will take care of it (if needed).
+         */
+        const shouldIgnoreEvent = this.sasVerificationInProgress?.channel.id === txnId;
+        if (shouldIgnoreEvent) { return; }
+        /**
+         * 1. If we receive the cancel message, we need to update the requests map.
+         * 2. If we receive an starting message (viz request/start), we need to create the SASRequest from it.
+         */
+        switch (event.type) {
+            case VerificationEventType.Cancel: 
+                this.receivedSASVerifications.remove(txnId);
+                return;
+            case VerificationEventType.Request:
+            case VerificationEventType.Start:
+                this.platform.logger.run("Create SASRequest", () => {
+                    this.receivedSASVerifications.set(txnId, new SASRequest(event));
+                });
+                return;
+            default:
+                // we don't care about this event!
+                return;
+        }
+    }
+
     /** returns our own device key signed by our self-signing key. Other signatures will be missing. */
     async signOwnDevice(log: ILogItem): Promise<DeviceKey | undefined> {
         return log.wrap("CrossSigning.signOwnDevice", async log => {

src/matrix/verification/SAS/SASRequest.ts

@@ -0,0 +1,31 @@
+/*
+Copyright 2023 The Matrix.org Foundation C.I.C.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+export class SASRequest {
+    constructor(public readonly startingMessage: any) {}
+
+    get deviceId(): string {
+        return this.startingMessage.content.from_device;
+    }
+
+    get sender(): string {
+        return this.startingMessage.sender;
+    }
+
+    get id(): string {
+        return this.startingMessage.content.transaction_id;
+    }
+}

src/matrix/verification/SAS/SASVerification.ts

@@ -19,14 +19,14 @@ import type {BaseSASVerificationStage} from "./stages/BaseSASVerificationStage";
 import type {Account} from "../../e2ee/Account.js";
 import type {DeviceTracker} from "../../e2ee/DeviceTracker.js";
 import type * as OlmNamespace from "@matrix-org/olm";
-import {IChannel} from "./channel/Channel";
+import type {IChannel} from "./channel/Channel";
-import {HomeServerApi} from "../../net/HomeServerApi";
+import type {HomeServerApi} from "../../net/HomeServerApi";
+import type {Timeout} from "../../../platform/types/types";
+import type {Clock} from "../../../platform/web/dom/Clock.js";
 import {CancelReason, VerificationEventType} from "./channel/types";
 import {SendReadyStage} from "./stages/SendReadyStage";
 import {SelectVerificationMethodStage} from "./stages/SelectVerificationMethodStage";
 import {VerificationCancelledError} from "./VerificationCancelledError";
-import {Timeout} from "../../../platform/types/types";
-import {Clock} from "../../../platform/web/dom/Clock.js";
 import {EventEmitter} from "../../../utils/EventEmitter";
 import {SASProgressEvents} from "./types";
 
@@ -84,6 +84,10 @@ export class SASVerification extends EventEmitter<SASProgressEvents> {
         }
     }
 
+    async abort() {
+        await this.channel.cancelVerification(CancelReason.UserCancelled);
+    }
+
     async start() {
         try {
             let stage = this.startStage;
@@ -98,6 +102,9 @@ export class SASVerification extends EventEmitter<SASProgressEvents> {
             }
         }
         finally {
+            if (this.channel.isCancelled) {
+                this.emit("VerificationCancelled", this.channel.cancellation);
+            }
             this.olmSas.free();
             this.timeout.abort();
             this.finished = true;
@@ -163,6 +170,9 @@ export function tests() {
                     device_id: deviceId,
                     keys: {
                         [`ed25519:${deviceId}`]: "D8w9mrokGdEZPdPgrU0kQkYi4vZyzKEBfvGyZsGK7+Q",
+                    },
+                    unsigned: {
+                        device_display_name: "lala10",
                     }
                 };
             },

src/matrix/verification/SAS/channel/Channel.ts

@@ -49,6 +49,8 @@ export interface IChannel {
     acceptMessage: any;
     startMessage: any;
     initiatedByUs: boolean;
+    isCancelled: boolean;
+    cancellation?: { code: CancelReason, cancelledByUs: boolean };
     id: string;
     otherUserDeviceId: string;
 } 
@@ -78,7 +80,7 @@ export class ToDeviceChannel extends Disposables implements IChannel {
     public startMessage: any;
     public id: string;
     private _initiatedByUs: boolean;
-    private _isCancelled = false;
+    private _cancellation?: { code: CancelReason, cancelledByUs: boolean };
 
     /**
      * 
@@ -116,8 +118,12 @@ export class ToDeviceChannel extends Disposables implements IChannel {
         }
     }
 
+    get cancellation(): IChannel["cancellation"] {
+        return this._cancellation;
+    };
+
     get isCancelled(): boolean {
-        return this._isCancelled;
+        return !!this._cancellation;
     }
 
     async send(eventType: VerificationEventType, content: any, log: ILogItem): Promise<void> {
@@ -199,7 +205,7 @@ export class ToDeviceChannel extends Disposables implements IChannel {
                 return;
             }
             if (event.type === VerificationEventType.Cancel) {
-                this._isCancelled = true;
+                this._cancellation = { code: event.content.code, cancelledByUs: false };
                 this.dispose();
                 return;
             }
@@ -234,7 +240,7 @@ export class ToDeviceChannel extends Disposables implements IChannel {
             const payload = {
                 messages: {
                     [this.otherUserId]: {
-                        [this.otherUserDeviceId]: {
+                        [this.otherUserDeviceId ?? "*"]: {
                             code: cancellationType,
                             reason: messageFromErrorType[cancellationType],
                             transaction_id: this.id,
@@ -243,7 +249,7 @@ export class ToDeviceChannel extends Disposables implements IChannel {
                 }
             }
             await this.hsApi.sendToDevice(VerificationEventType.Cancel, payload, makeTxnId(), { log }).response();
-            this._isCancelled = true;
+            this._cancellation = { code: cancellationType, cancelledByUs: true };
             this.dispose();
         });
     }
@@ -258,7 +264,7 @@ export class ToDeviceChannel extends Disposables implements IChannel {
     }
 
     waitForEvent(eventType: VerificationEventType): Promise<any> {
-        if (this._isCancelled) {
+        if (this.isCancelled) {
             throw new VerificationCancelledError();
         }
         // Check if we already received the message

src/matrix/verification/SAS/channel/MockChannel.ts

@@ -17,6 +17,7 @@ export class MockChannel implements ITestChannel {
     public initiatedByUs: boolean;
     public startMessage: any;
     public isCancelled: boolean = false;
+    public cancellation: { code: CancelReason; cancelledByUs: boolean; };
     private olmSas: any;
 
     constructor(

src/matrix/verification/SAS/stages/SelectVerificationMethodStage.ts

@@ -23,9 +23,11 @@ import type {ILogItem} from "../../../../logging/types";
 export class SelectVerificationMethodStage extends BaseSASVerificationStage {
     private hasSentStartMessage = false;
     private allowSelection = true;
+    public otherDeviceName: string;
 
     async completeStage() {
         await this.log.wrap("SelectVerificationMethodStage.completeStage", async (log) => {
+            await this.findDeviceName(log);
             this.eventEmitter.emit("SelectVerificationStage", this);
             const startMessage = this.channel.waitForEvent(VerificationEventType.Start);
             const acceptMessage = this.channel.waitForEvent(VerificationEventType.Accept);
@@ -81,6 +83,17 @@ export class SelectVerificationMethodStage extends BaseSASVerificationStage {
         });
     }
 
+    private async findDeviceName(log: ILogItem) {
+        await log.wrap("SelectVerificationMethodStage.findDeviceName", async () => {
+            const device = await this.options.deviceTracker.deviceForId(this.otherUserId, this.otherUserDeviceId, this.options.hsApi, log);
+            if (!device) {
+                log.log({ l: "Cannot find device", userId: this.otherUserId, deviceId: this.otherUserDeviceId });
+                throw new Error("Cannot find device");
+            }
+            this.otherDeviceName = device.unsigned.device_display_name ?? device.device_id;
+        })
+    }
+
     async selectEmojiMethod(log: ILogItem) {
         if (!this.allowSelection) { return; } 
         const content = {

src/matrix/verification/SAS/stages/SendDoneStage.ts

@@ -19,6 +19,7 @@ import {VerificationEventType} from "../channel/types";
 export class SendDoneStage extends BaseSASVerificationStage {
     async completeStage() {
         await this.log.wrap("SendDoneStage.completeStage", async (log) => {
+            this.eventEmitter.emit("VerificationCompleted", this.otherUserDeviceId);
             await this.channel.send(VerificationEventType.Done, {}, log);
         });
     }

src/matrix/verification/SAS/stages/SendMacStage.ts

@@ -44,7 +44,7 @@ export class SendMacStage extends BaseSASVerificationStage {
             this.channel.id;
 
         const deviceKeyId = `ed25519:${this.ourUserDeviceId}`;
-        const deviceKeys = this.e2eeAccount.getDeviceKeysToSignWithCrossSigning();
+        const deviceKeys = this.e2eeAccount.getUnsignedDeviceKey();
         mac[deviceKeyId] = calculateMAC(deviceKeys.keys[deviceKeyId], baseInfo + deviceKeyId);
         keyList.push(deviceKeyId);
 

src/matrix/verification/SAS/types.ts

@@ -13,10 +13,13 @@ WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 See the License for the specific language governing permissions and
 limitations under the License.
 */
-import {CalculateSASStage} from "./stages/CalculateSASStage";
+import type {IChannel} from "./channel/Channel";
-import {SelectVerificationMethodStage} from "./stages/SelectVerificationMethodStage";
+import type {CalculateSASStage} from "./stages/CalculateSASStage";
+import type {SelectVerificationMethodStage} from "./stages/SelectVerificationMethodStage";
 
 export type SASProgressEvents = {
     SelectVerificationStage: SelectVerificationMethodStage;
     EmojiGenerated: CalculateSASStage;
+    VerificationCompleted: string;
+    VerificationCancelled: IChannel["cancellation"];
 }

src/platform/web/ui/css/themes/element/theme.css

@@ -1264,27 +1264,52 @@ button.RoomDetailsView_row::after {
     padding: 0;
 }
 
+.VerificationToastNotificationView:not(:first-child),
 .CallToastNotificationView:not(:first-child) {
     margin-top: 12px;
 }
 
+.VerificationToastNotificationView {
+    display: flex;
+    flex-direction: column;
+}
+
 .CallToastNotificationView {
     display: grid;
     grid-template-rows: 40px 1fr 1fr 48px;
     row-gap: 4px;
-    width: 260px;
+}
+
+
+.VerificationToastNotificationView,
+.CallToastNotificationView {
     background-color: var(--background-color-secondary);
     border-radius: 8px;
     color: var(--text-color);
     box-shadow: 2px 2px 10px rgba(0, 0, 0, 0.5);
 }
 
+.CallToastNotificationView {
+    width: 260px;
+}
+
+.VerificationToastNotificationView {
+    width: 248px;
+}
+
+.VerificationToastNotificationView__top {
+    padding: 8px;
+    display: flex;
+}
+
 .CallToastNotificationView__top {
     display: grid;
     grid-template-columns: auto 176px auto;
     align-items: center;
     justify-items: center;
 }
+
+.VerificationToastNotificationView__dismiss-btn,
 .CallToastNotificationView__dismiss-btn {
     background: center var(--background-color-secondary--darker-5) url("./icons/dismiss.svg?primary=text-color") no-repeat;
     border-radius: 100%;
@@ -1292,11 +1317,16 @@ button.RoomDetailsView_row::after {
     width: 15px;
 }
 
+.VerificationToastNotificationView__title,
 .CallToastNotificationView__name {
     font-weight: 600;
     width: 100%;
 }
 
+.VerificationToastNotificationView__description {
+    padding: 8px;
+}
+
 .CallToastNotificationView__description {
     margin-left: 42px;
 }
@@ -1350,7 +1380,105 @@ button.RoomDetailsView_row::after {
     margin-right: 10px;
 }
 
+.VerificationToastNotificationView__action {
+    display: flex;
+    justify-content: space-between;
+    padding: 8px;
+}
+
 .CallToastNotificationView__action .button-action {
     width: 100px;
     height: 40px;
 }
+
+.VerificationToastNotificationView__action .button-action {
+    width: 100px;
+    height: 32px;
+    display: flex;
+    align-items: center;
+    justify-content: center;
+}
+
+.VerificationCompleteView,
+.DeviceVerificationView,
+.SelectMethodView {
+    display: flex;
+    align-items: center;
+    justify-content: center;
+    flex-direction: column;
+}
+
+.VerificationCompleteView__heading,
+.VerifyEmojisView__heading,
+.SelectMethodView__heading,
+.WaitingForOtherUserView__heading {
+    display: flex;
+    align-items: center;
+    gap: 16px;
+    flex-wrap: wrap;
+    justify-content: center;
+    padding: 8px;
+}
+
+.VerificationCompleteView>*,
+.SelectMethodView>*,
+.VerifyEmojisView>*,
+.WaitingForOtherUserView>* {
+    padding: 16px;
+}
+
+.VerificationCompleteView__title,
+.VerifyEmojisView__title,
+.SelectMethodView__title,
+.WaitingForOtherUserView__title,
+.VerificationCancelledView__description,
+.VerificationCompleteView__description,
+.VerifyEmojisView__description,
+.SelectMethodView__description,
+.WaitingForOtherUserView__description {
+    text-align: center;
+    margin: 0;
+}
+
+.VerificationCancelledView__actions,
+.SelectMethodView__actions,
+.VerifyEmojisView__actions,
+.WaitingForOtherUserView__actions {
+    display: flex;
+    justify-content: center;
+    gap: 12px;
+    padding: 16px;
+}
+
+.EmojiCollection {
+    display: flex;
+    justify-content: center;
+    gap: 16px;
+}
+
+.EmojiContainer__emoji {
+    font-size: 3.2rem;
+}
+
+.VerifyEmojisView__waiting,
+.EmojiContainer__name,
+.EmojiContainer__emoji {
+    display: flex;
+    justify-content: center;
+    align-items: center;
+}
+
+.EmojiContainer__name {
+    font-weight: bold;
+}
+
+.VerifyEmojisView__waiting {
+    gap: 12px;
+}
+
+.VerificationCompleteView__icon {
+    background: url("./icons/verified.svg?primary=accent-color") no-repeat;
+    background-size: contain;
+    width: 128px;
+    height: 128px;
+}

src/platform/web/ui/session/SessionView.js

@@ -30,6 +30,7 @@ import {CreateRoomView} from "./CreateRoomView.js";
 import {RightPanelView} from "./rightpanel/RightPanelView.js";
 import {viewClassForTile} from "./room/common";
 import {JoinRoomView} from "./JoinRoomView";
+import {DeviceVerificationView} from "./verification/DeviceVerificationView";
 import {ToastCollectionView} from "./toast/ToastCollectionView";
 
 export class SessionView extends TemplateView {
@@ -53,6 +54,8 @@ export class SessionView extends TemplateView {
                     return new CreateRoomView(vm.createRoomViewModel);
                 } else if (vm.joinRoomViewModel) {
                     return new JoinRoomView(vm.joinRoomViewModel);
+                } else if (vm.verificationViewModel) {
+                    return new DeviceVerificationView(vm.verificationViewModel);
                 } else if (vm.currentRoomViewModel) {
                     if (vm.currentRoomViewModel.kind === "invite") {
                         return new InviteView(vm.currentRoomViewModel);

src/platform/web/ui/session/settings/KeyBackupSettingsView.ts

@@ -62,11 +62,24 @@ export class KeyBackupSettingsView extends TemplateView<KeyBackupViewModel> {
                 return t.p("Cross-signing master key found and trusted.")
             }),
             t.if(vm => vm.canSignOwnDevice, t => {
-                return t.button({
+                return t.div([
-                    onClick: disableTargetCallback(async () => {
+                    t.button(
-                        await vm.signOwnDevice();
+                        {
-                    })
+                            onClick: disableTargetCallback(async (evt) => {
-                }, "Sign own device");
+                                await vm.signOwnDevice();
+                            }),
+                        },
+                        "Sign own device"
+                    ),
+                    t.button(
+                        {
+                            onClick: disableTargetCallback(async () => {
+                                vm.navigateToVerification();
+                            }),
+                        },
+                        "Verify by emoji"
+                    ),
+                ]);
             }),
 
         ]);

src/platform/web/ui/session/toast/ToastCollectionView.ts

@@ -15,17 +15,21 @@ limitations under the License.
 */
 
 import {CallToastNotificationView} from "./CallToastNotificationView";
+import {VerificationToastNotificationView} from "./VerificationToastNotificationView";
 import {ListView} from "../../general/ListView";
 import {TemplateView, Builder} from "../../general/TemplateView";
 import type {IView} from "../../general/types";
 import type {CallToastNotificationViewModel} from "../../../../../domain/session/toast/calls/CallToastNotificationViewModel";
 import type {ToastCollectionViewModel} from "../../../../../domain/session/toast/ToastCollectionViewModel";
 import type {BaseToastNotificationViewModel} from "../../../../../domain/session/toast/BaseToastNotificationViewModel";
+import type {VerificationToastNotificationViewModel} from "../../../../../domain/session/toast/verification/VerificationToastNotificationViewModel";
 
 function toastViewModelToView(vm: BaseToastNotificationViewModel): IView {
     switch (vm.kind) {
         case "calls":
             return new CallToastNotificationView(vm as CallToastNotificationViewModel); 
+        case "verification":
+            return new VerificationToastNotificationView(vm as VerificationToastNotificationViewModel);
         default:
             throw new Error(`Cannot find view class for notification kind ${vm.kind}`);
     }
@@ -33,12 +37,13 @@ function toastViewModelToView(vm: BaseToastNotificationViewModel): IView {
 
 export class ToastCollectionView extends TemplateView<ToastCollectionViewModel> {
     render(t: Builder<ToastCollectionViewModel>, vm: ToastCollectionViewModel) {
-        const view = new ListView({
-            list: vm.toastViewModels,
-            parentProvidesUpdates: false,
-        }, (vm: CallToastNotificationViewModel) => toastViewModelToView(vm));
         return t.div({ className: "ToastCollectionView" }, [
-            t.view(view),
+            t.ifView(vm => !!vm.toastViewModels, t => {
+                return new ListView({
+                    list: vm.toastViewModels,
+                    parentProvidesUpdates: false,
+                }, (vm: CallToastNotificationViewModel) => toastViewModelToView(vm));
+            }),
         ]);
     }
 }

src/platform/web/ui/session/toast/VerificationToastNotificationView.ts

@@ -0,0 +1,45 @@
+/*
+Copyright 2023 The Matrix.org Foundation C.I.C.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+import {TemplateView, Builder} from "../../general/TemplateView";
+import type {VerificationToastNotificationViewModel} from "../../../../../domain/session/toast/verification/VerificationToastNotificationViewModel";
+
+export class VerificationToastNotificationView extends TemplateView<VerificationToastNotificationViewModel> {
+    render(t: Builder<VerificationToastNotificationViewModel>, vm: VerificationToastNotificationViewModel) {
+        return t.div({ className: "VerificationToastNotificationView" }, [
+            t.div({ className: "VerificationToastNotificationView__top" }, [
+                t.span({ className: "VerificationToastNotificationView__title" },
+                    vm.i18n`Device Verification`),
+                t.button({
+                    className: "button-action VerificationToastNotificationView__dismiss-btn",
+                    onClick: () => vm.dismiss(),
+                }),
+            ]),
+            t.div({ className: "VerificationToastNotificationView__description" }, [
+                t.span(vm.i18n`Do you want to verify device ${vm.otherDeviceId}?`),
+            ]),
+            t.div({ className: "VerificationToastNotificationView__action" }, [
+                t.button({
+                    className: "button-action primary destructive",
+                    onClick: () => vm.dismiss(),
+                }, vm.i18n`Ignore`),
+                t.button({
+                    className: "button-action primary",
+                    onClick: () => vm.accept(),
+                }, vm.i18n`Accept`),
+            ]),
+        ]);
+    }
+}

src/platform/web/ui/session/verification/DeviceVerificationView.ts

@@ -0,0 +1,45 @@
+/*
+Copyright 2022 The Matrix.org Foundation C.I.C.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+import {Builder, TemplateView} from "../../general/TemplateView";
+import {DeviceVerificationViewModel} from "../../../../../domain/session/verification/DeviceVerificationViewModel";
+import {WaitingForOtherUserView} from "./stages/WaitingForOtherUserView";
+import {VerificationCancelledView} from "./stages/VerificationCancelledView";
+import {SelectMethodView} from "./stages/SelectMethodView";
+import {VerifyEmojisView} from "./stages/VerifyEmojisView";
+import {VerificationCompleteView} from "./stages/VerificationCompleteView";
+
+export class DeviceVerificationView extends TemplateView<DeviceVerificationViewModel> {
+    render(t: Builder<DeviceVerificationViewModel>) {
+        return t.div({
+            className: {
+                "middle": true,
+                "DeviceVerificationView": true,
+            }
+        }, [
+            t.mapView(vm => vm.currentStageViewModel, (vm) => {
+                switch (vm?.kind) {
+                    case "waiting-for-user": return new WaitingForOtherUserView(vm);
+                    case "verification-cancelled": return new VerificationCancelledView(vm);
+                    case "select-method": return new SelectMethodView(vm);
+                    case "verify-emojis": return new VerifyEmojisView(vm);
+                    case "verification-completed": return new VerificationCompleteView(vm);
+                    default: return null;
+                }
+            })
+        ])
+    }
+}

src/platform/web/ui/session/verification/stages/SelectMethodView.ts

@@ -0,0 +1,62 @@
+/*
+Copyright 2023 The Matrix.org Foundation C.I.C.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+import {Builder, TemplateView} from "../../../general/TemplateView";
+import {spinner} from "../../../common.js"
+import type {SelectMethodViewModel} from "../../../../../../domain/session/verification/stages/SelectMethodViewModel";
+
+export class SelectMethodView extends TemplateView<SelectMethodViewModel> {
+    render(t: Builder<SelectMethodViewModel>) {
+        return t.div({ className: "SelectMethodView" }, [
+            t.map(vm => vm.hasProceeded, (hasProceeded, t, vm) => {
+                if (hasProceeded) {
+                    return spinner(t);
+                }
+                else return t.div([
+                    t.div({ className: "SelectMethodView__heading" }, [
+                        t.h2( { className: "SelectMethodView__title" }, vm.i18n`Verify device '${vm.deviceName}' by comparing emojis?`),
+                    ]),
+                    t.p({ className: "SelectMethodView__description" },
+                        vm.i18n`You are about to verify your other device by comparing emojis.`
+                    ),
+                    t.div({ className: "SelectMethodView__actions" }, [
+                        t.button(
+                            {
+                                className: {
+                                    "button-action": true,
+                                    primary: true,
+                                    destructive: true,
+                                },
+                                onclick: () => vm.cancel(),
+                            },
+                            "Cancel"
+                        ),
+                        t.button(
+                            {
+                                className: {
+                                    "button-action": true,
+                                    primary: true,
+                                },
+                                onclick: () => vm.proceed(),
+                            },
+                            "Proceed"
+                        ),
+                    ]),
+                ]);
+            }),
+        ]);
+    }
+}

src/platform/web/ui/session/verification/stages/VerificationCancelledView.ts

@@ -0,0 +1,78 @@
+/*
+Copyright 2023 The Matrix.org Foundation C.I.C.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+import {Builder, TemplateView} from "../../../general/TemplateView";
+import {VerificationCancelledViewModel} from "../../../../../../domain/session/verification/stages/VerificationCancelledViewModel";
+import {CancelReason} from "../../../../../../matrix/verification/SAS/channel/types";
+
+export class VerificationCancelledView extends TemplateView<VerificationCancelledViewModel> {
+    render(t: Builder<VerificationCancelledViewModel>, vm: VerificationCancelledViewModel) {
+        const headerTextStart = vm.isCancelledByUs ? "You" : "The other device";
+
+        return t.div(
+            {
+                className: "VerificationCancelledView",
+            },
+            [
+                t.h2(
+                    { className: "VerificationCancelledView__title" },
+                    vm.i18n`${headerTextStart} cancelled the verification!`
+                ),
+                t.p(
+                    { className: "VerificationCancelledView__description" },
+                   vm.i18n`${this.getDescriptionFromCancellationCode(vm.cancelCode, vm.isCancelledByUs)}` 
+                ),
+                t.div({ className: "VerificationCancelledView__actions" }, [
+                    t.button({
+                        className: {
+                            "button-action": true,
+                            "primary": true,
+                        },
+                        onclick: () => vm.gotoSettings(),
+                    }, "Got it")
+                ]),
+            ]
+        );
+    }
+
+    getDescriptionFromCancellationCode(code: CancelReason, isCancelledByUs: boolean): string {
+        const descriptionsWhenWeCancelled = {
+            [CancelReason.InvalidMessage]: "You other device sent an invalid message.",
+            [CancelReason.KeyMismatch]: "The key could not be verified.",
+            [CancelReason.TimedOut]: "The verification process timed out.",
+            [CancelReason.UnexpectedMessage]: "Your other device sent an unexpected message.",
+            [CancelReason.UnknownMethod]: "Your other device is using an unknown method for verification.",
+            [CancelReason.UnknownTransaction]: "Your other device sent a message with an unknown transaction id.",
+            [CancelReason.UserMismatch]: "The expected user did not match the user verified.",
+            [CancelReason.MismatchedCommitment]: "The hash commitment does not match.",
+            [CancelReason.MismatchedSAS]: "The emoji/decimal did not match.",
+        }
+        const descriptionsWhenTheyCancelled = {
+            [CancelReason.UserCancelled]: "Your other device cancelled the verification!",
+            [CancelReason.InvalidMessage]: "Invalid message sent to the other device.",
+            [CancelReason.KeyMismatch]: "The other device could not verify our keys",
+            [CancelReason.TimedOut]: "The verification process timed out.",
+            [CancelReason.UnexpectedMessage]: "Unexpected message sent to the other device.",
+            [CancelReason.UnknownMethod]: "Your other device does not understand the method you chose",
+            [CancelReason.UnknownTransaction]: "Your other device rejected our message.",
+            [CancelReason.UserMismatch]: "The expected user did not match the user verified.",
+            [CancelReason.MismatchedCommitment]: "Your other device was not able to verify the hash commitment",
+            [CancelReason.MismatchedSAS]: "The emoji/decimal did not match.",
+        }
+        const map = isCancelledByUs ? descriptionsWhenWeCancelled : descriptionsWhenTheyCancelled;
+        return map[code] ?? "";
+    }
+}

src/platform/web/ui/session/verification/stages/VerificationCompleteView.ts

@@ -0,0 +1,45 @@
+/*
+Copyright 2023 The Matrix.org Foundation C.I.C.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+import {Builder, TemplateView} from "../../../general/TemplateView";
+import type {VerificationCompleteViewModel} from "../../../../../../domain/session/verification/stages/VerificationCompleteViewModel";
+
+export class VerificationCompleteView extends TemplateView<VerificationCompleteViewModel> {
+    render(t: Builder<VerificationCompleteViewModel>, vm: VerificationCompleteViewModel) {
+        return t.div({ className: "VerificationCompleteView" }, [
+            t.div({className: "VerificationCompleteView__icon"}),
+            t.div({ className: "VerificationCompleteView__heading" }, [
+                t.h2(
+                    { className: "VerificationCompleteView__title" },
+                    vm.i18n`Verification completed successfully!`
+                ),
+            ]),
+            t.p(
+                { className: "VerificationCompleteView__description" },
+                vm.i18n`You successfully verified device ${vm.otherDeviceId}`
+            ),
+            t.div({ className: "VerificationCompleteView__actions" }, [
+                t.button({
+                    className: {
+                        "button-action": true,
+                        "primary": true,
+                    },
+                    onclick: () => vm.gotoSettings(),
+                }, "Got it")
+            ]),
+        ]);
+    }
+}

src/platform/web/ui/session/verification/stages/VerifyEmojisView.ts

@@ -0,0 +1,79 @@
+/*
+Copyright 2023 The Matrix.org Foundation C.I.C.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+import {Builder, TemplateView} from "../../../general/TemplateView";
+import {spinner} from "../../../common.js"
+import type {VerifyEmojisViewModel} from "../../../../../../domain/session/verification/stages/VerifyEmojisViewModel";
+
+export class VerifyEmojisView extends TemplateView<VerifyEmojisViewModel> {
+    render(t: Builder<VerifyEmojisViewModel>, vm: VerifyEmojisViewModel) {
+        const emojiList = vm.emojis.reduce((acc, [emoji, name]) => {
+            const e = t.div({ className: "EmojiContainer" }, [
+                t.div({ className: "EmojiContainer__emoji" }, emoji),
+                t.div({ className: "EmojiContainer__name" }, name),
+            ]);
+            acc.push(e);
+            return acc;
+        }, [] as any);
+        const emojiCollection = t.div({ className: "EmojiCollection" }, emojiList);
+        return t.div({ className: "VerifyEmojisView" }, [
+            t.div({ className: "VerifyEmojisView__heading" }, [
+                t.h2(
+                    { className: "VerifyEmojisView__title" },
+                    vm.i18n`Do the emojis match?`
+                ),
+            ]),
+            t.p(
+                { className: "VerifyEmojisView__description" },
+                vm.i18n`Confirm the emoji below are displayed on both devices, in the same order:`
+            ),
+            t.div({ className: "VerifyEmojisView__emojis" }, emojiCollection),
+            t.map(vm => vm.isWaiting, (isWaiting, t, vm) => {
+                if (isWaiting) {
+                    return t.div({ className: "VerifyEmojisView__waiting" }, [
+                        spinner(t),
+                        t.span(vm.i18n`Waiting for you to verify on your other device`),
+                    ]);
+                }
+                else {
+                    return t.div({ className: "VerifyEmojisView__actions" }, [
+                        t.button(
+                            {
+                                className: {
+                                    "button-action": true,
+                                    primary: true,
+                                    destructive: true,
+                                },
+                                onclick: () => vm.setEmojiMatch(false),
+                            },
+                            vm.i18n`They don't match`
+                        ),
+                        t.button(
+                            {
+                                className: {
+                                    "button-action": true,
+                                    primary: true,
+                                },
+                                onclick: () => vm.setEmojiMatch(true),
+                            },
+                            vm.i18n`They match`
+                        ),
+                    ]);
+                }
+            })
+        ]);
+    }
+}

src/platform/web/ui/session/verification/stages/WaitingForOtherUserView.ts

@@ -0,0 +1,46 @@
+/*
+Copyright 2023 The Matrix.org Foundation C.I.C.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+import {Builder, TemplateView} from "../../../general/TemplateView";
+import {spinner} from "../../../common.js";
+import {WaitingForOtherUserViewModel} from "../../../../../../domain/session/verification/stages/WaitingForOtherUserViewModel";
+
+export class WaitingForOtherUserView extends TemplateView<WaitingForOtherUserViewModel> {
+    render(t: Builder<WaitingForOtherUserViewModel>, vm: WaitingForOtherUserViewModel) {
+        return t.div({ className: "WaitingForOtherUserView" }, [
+            t.div({ className: "WaitingForOtherUserView__heading" }, [
+                spinner(t),
+                t.h2(
+                    { className: "WaitingForOtherUserView__title" },
+                    vm.i18n`Waiting for any of your device to accept the verification request`
+                ),
+            ]),
+            t.p({ className: "WaitingForOtherUserView__description" },
+                vm.i18n`Accept the request from the device you wish to verify!`
+            ),
+            t.div({ className: "WaitingForOtherUserView__actions" },
+                t.button({
+                    className: {
+                        "button-action": true,
+                        "primary": true,
+                        "destructive": true,
+                    },
+                    onclick: () => vm.cancel(),
+                }, "Cancel")
+            ),
+        ]);
+    }
+}