diff --git a/src/components/views/right_panel/UserInfo.js b/src/components/views/right_panel/UserInfo.js
index 24c5489c4f..4219da690e 100644
--- a/src/components/views/right_panel/UserInfo.js
+++ b/src/components/views/right_panel/UserInfo.js
@@ -25,7 +25,7 @@ import dis from '../../../dispatcher';
 import Modal from '../../../Modal';
 import * as sdk from '../../../index';
 import { _t } from '../../../languageHandler';
-import createRoom, {findDMForUser} from '../../../createRoom';
+import createRoom from '../../../createRoom';
 import DMRoomMap from '../../../utils/DMRoomMap';
 import AccessibleButton from '../elements/AccessibleButton';
 import SdkConfig from '../../../SdkConfig';
@@ -43,6 +43,7 @@ import MatrixClientContext from "../../../contexts/MatrixClientContext";
 import {RIGHT_PANEL_PHASES} from "../../../stores/RightPanelStorePhases";
 import EncryptionPanel from "./EncryptionPanel";
 import { useAsyncMemo } from '../../../hooks/useAsyncMemo';
+import { verifyUser, legacyVerifyUser, verifyDevice } from '../../../verification';
 
 const _disambiguateDevices = (devices) => {
     const names = Object.create(null);
@@ -153,66 +154,6 @@ function useHasCrossSigningKeys(cli, member, canVerify, setUpdating) {
     }, [cli, member, canVerify], false);
 }
 
-async function verifyDevice(userId, device) {
-    const cli = MatrixClientPeg.get();
-    const member = cli.getUser(userId);
-    const QuestionDialog = sdk.getComponent("dialogs.QuestionDialog");
-    Modal.createTrackedDialog("Verification warning", "unverified session", QuestionDialog, {
-        headerImage: require("../../../../res/img/e2e/warning.svg"),
-        title: _t("Not Trusted"),
-        description: <div>
-            <p>{_t("%(name)s (%(userId)s) signed in to a new session without verifying it:", {name: member.displayName, userId})}</p>
-            <p>{device.getDisplayName()} ({device.deviceId})</p>
-            <p>{_t("Ask this user to verify their session, or manually verify it below.")}</p>
-        </div>,
-        onFinished: async (doneClicked) => {
-            const manuallyVerifyClicked = !doneClicked;
-            if (!manuallyVerifyClicked) {
-                return;
-            }
-            const cli = MatrixClientPeg.get();
-            const verificationRequestPromise = cli.requestVerification(
-                userId,
-                [device.deviceId],
-            );
-            dis.dispatch({
-                action: "set_right_panel_phase",
-                phase: RIGHT_PANEL_PHASES.EncryptionPanel,
-                refireParams: {member, verificationRequestPromise},
-            });
-        },
-        primaryButton: _t("Done"),
-        cancelButton: _t("Manually Verify"),
-    });
-}
-
-async function legacyVerifyUser(member) {
-    const cli = MatrixClientPeg.get();
-    const verificationRequestPromise = cli.requestVerification(member.userId);
-    dis.dispatch({
-        action: "set_right_panel_phase",
-        phase: RIGHT_PANEL_PHASES.EncryptionPanel,
-        refireParams: {member, verificationRequestPromise},
-    });
-}
-
-function verifyUser(user) {
-    const cli = MatrixClientPeg.get();
-    const dmRoom = findDMForUser(cli, user.userId);
-    let existingRequest;
-    if (dmRoom) {
-        existingRequest = cli.findVerificationRequestDMInProgress(dmRoom.roomId);
-    }
-    dis.dispatch({
-        action: "set_right_panel_phase",
-        phase: RIGHT_PANEL_PHASES.EncryptionPanel,
-        refireParams: {
-            member: user,
-            verificationRequest: existingRequest,
-        },
-    });
-}
-
 function DeviceItem({userId, device}) {
     const cli = useContext(MatrixClientContext);
     const isMe = userId === cli.getUserId();
@@ -239,7 +180,7 @@ function DeviceItem({userId, device}) {
 
     const onDeviceClick = () => {
         if (!isVerified) {
-            verifyDevice(userId, device);
+            verifyDevice(cli.getUser(userId), device);
         }
     };
 
diff --git a/src/components/views/toasts/VerificationRequestToast.js b/src/components/views/toasts/VerificationRequestToast.js
index c11cefc839..f590cecc3e 100644
--- a/src/components/views/toasts/VerificationRequestToast.js
+++ b/src/components/views/toasts/VerificationRequestToast.js
@@ -24,6 +24,7 @@ import {userLabelForEventRoom} from "../../../utils/KeyVerificationStateObserver
 import dis from "../../../dispatcher";
 import ToastStore from "../../../stores/ToastStore";
 import Modal from "../../../Modal";
+import {enable4SIfNeeded} from "../../../verification";
 
 export default class VerificationRequestToast extends React.PureComponent {
     constructor(props) {
@@ -73,6 +74,9 @@ export default class VerificationRequestToast extends React.PureComponent {
     }
 
     accept = async () => {
+        if (!await enable4SIfNeeded()) {
+            return;
+        }
         ToastStore.sharedInstance().dismissToast(this.props.toastKey);
         const {request} = this.props;
         // no room id for to_device requests
diff --git a/src/i18n/strings/en_EN.json b/src/i18n/strings/en_EN.json
index 15a050d783..2f8f5c48ad 100644
--- a/src/i18n/strings/en_EN.json
+++ b/src/i18n/strings/en_EN.json
@@ -291,6 +291,11 @@
     "%(senderName)s updated a ban rule that was matching %(oldGlob)s to matching %(newGlob)s for %(reason)s": "%(senderName)s updated a ban rule that was matching %(oldGlob)s to matching %(newGlob)s for %(reason)s",
     "Light theme": "Light theme",
     "Dark theme": "Dark theme",
+    "Not Trusted": "Not Trusted",
+    "%(name)s (%(userId)s) signed in to a new session without verifying it:": "%(name)s (%(userId)s) signed in to a new session without verifying it:",
+    "Ask this user to verify their session, or manually verify it below.": "Ask this user to verify their session, or manually verify it below.",
+    "Done": "Done",
+    "Manually Verify": "Manually Verify",
     "%(displayName)s is typing …": "%(displayName)s is typing …",
     "%(names)s and %(count)s others are typing …|other": "%(names)s and %(count)s others are typing …",
     "%(names)s and %(count)s others are typing …|one": "%(names)s and one other is typing …",
@@ -1185,11 +1190,6 @@
     "Yours, or the other users’ session": "Yours, or the other users’ session",
     "Members": "Members",
     "Files": "Files",
-    "Not Trusted": "Not Trusted",
-    "%(name)s (%(userId)s) signed in to a new session without verifying it:": "%(name)s (%(userId)s) signed in to a new session without verifying it:",
-    "Ask this user to verify their session, or manually verify it below.": "Ask this user to verify their session, or manually verify it below.",
-    "Done": "Done",
-    "Manually Verify": "Manually Verify",
     "Trusted": "Trusted",
     "Not trusted": "Not trusted",
     "%(count)s verified sessions|other": "%(count)s verified sessions",
diff --git a/src/verification.js b/src/verification.js
new file mode 100644
index 0000000000..235828dc92
--- /dev/null
+++ b/src/verification.js
@@ -0,0 +1,106 @@
+/*
+Copyright 2019, 2020 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 {MatrixClientPeg} from './MatrixClientPeg';
+import dis from "./dispatcher";
+import Modal from './Modal';
+import * as sdk from './index';
+import { _t } from './languageHandler';
+import {RIGHT_PANEL_PHASES} from "./stores/RightPanelStorePhases";
+import {findDMForUser} from './createRoom';
+import {accessSecretStorage} from './CrossSigningManager';
+import SettingsStore from './settings/SettingsStore';
+
+export async function enable4SIfNeeded() {
+    const cli = MatrixClientPeg.get();
+    if (!cli.isCryptoEnabled() || !SettingsStore.isFeatureEnabled("feature_cross_signing")) {
+        return false;
+    }
+    const usk = cli.getCrossSigningId("user_signing");
+    if (!usk) {
+        await accessSecretStorage();
+        return false;
+    }
+
+    return true;
+}
+
+export async function verifyDevice(user, device) {
+    if (!await enable4SIfNeeded()) {
+        return;
+    }
+    const QuestionDialog = sdk.getComponent("dialogs.QuestionDialog");
+    Modal.createTrackedDialog("Verification warning", "unverified session", QuestionDialog, {
+        headerImage: require("../res/img/e2e/warning.svg"),
+        title: _t("Not Trusted"),
+        description: <div>
+            <p>{_t("%(name)s (%(userId)s) signed in to a new session without verifying it:", {name: user.displayName, userId: user.userId})}</p>
+            <p>{device.getDisplayName()} ({device.deviceId})</p>
+            <p>{_t("Ask this user to verify their session, or manually verify it below.")}</p>
+        </div>,
+        onFinished: async (doneClicked) => {
+            const manuallyVerifyClicked = !doneClicked;
+            if (!manuallyVerifyClicked) {
+                return;
+            }
+            const cli = MatrixClientPeg.get();
+            const verificationRequestPromise = cli.requestVerification(
+                user.userId,
+                [device.deviceId],
+            );
+            dis.dispatch({
+                action: "set_right_panel_phase",
+                phase: RIGHT_PANEL_PHASES.EncryptionPanel,
+                refireParams: {member: user, verificationRequestPromise},
+            });
+        },
+        primaryButton: _t("Done"),
+        cancelButton: _t("Manually Verify"),
+    });
+}
+
+export async function legacyVerifyUser(user) {
+    if (!await enable4SIfNeeded()) {
+        return;
+    }
+    const cli = MatrixClientPeg.get();
+    const verificationRequestPromise = cli.requestVerification(user.userId);
+    dis.dispatch({
+        action: "set_right_panel_phase",
+        phase: RIGHT_PANEL_PHASES.EncryptionPanel,
+        refireParams: {member: user, verificationRequestPromise},
+    });
+}
+
+export async function verifyUser(user) {
+    if (!await enable4SIfNeeded()) {
+        return;
+    }
+    const cli = MatrixClientPeg.get();
+    const dmRoom = findDMForUser(cli, user.userId);
+    let existingRequest;
+    if (dmRoom) {
+        existingRequest = cli.findVerificationRequestDMInProgress(dmRoom.roomId);
+    }
+    dis.dispatch({
+        action: "set_right_panel_phase",
+        phase: RIGHT_PANEL_PHASES.EncryptionPanel,
+        refireParams: {
+            member: user,
+            verificationRequest: existingRequest,
+        },
+    });
+}