diff --git a/native/profile/secondary-device-qr-code-scanner.react.js b/native/profile/secondary-device-qr-code-scanner.react.js
index 6c32d9b00..0bc4be61a 100644
--- a/native/profile/secondary-device-qr-code-scanner.react.js
+++ b/native/profile/secondary-device-qr-code-scanner.react.js
@@ -1,332 +1,332 @@
 // @flow
 
 import { useNavigation } from '@react-navigation/native';
 import { BarCodeScanner, type BarCodeEvent } from 'expo-barcode-scanner';
 import invariant from 'invariant';
 import * as React from 'react';
 import { View } from 'react-native';
 
 import { parseDataFromDeepLink } from 'lib/facts/links.js';
 import { IdentityClientContext } from 'lib/shared/identity-client-context.js';
 import { useTunnelbroker } from 'lib/tunnelbroker/tunnelbroker-context.js';
 import {
   backupKeysValidator,
   type BackupKeys,
 } from 'lib/types/backup-types.js';
 import type { RawDeviceList } from 'lib/types/identity-service-types.js';
 import {
   tunnelbrokerMessageTypes,
   type TunnelbrokerMessage,
 } from 'lib/types/tunnelbroker/messages.js';
 import {
   peerToPeerMessageTypes,
   peerToPeerMessageValidator,
   type PeerToPeerMessage,
 } from 'lib/types/tunnelbroker/peer-to-peer-message-types.js';
 import { qrCodeAuthMessageTypes } from 'lib/types/tunnelbroker/qr-code-auth-message-types.js';
 import { assertWithValidator } from 'lib/utils/validation-utils.js';
 
 import type { ProfileNavigationProp } from './profile.react.js';
 import { getBackupSecret } from '../backup/use-client-backup.js';
 import { commCoreModule } from '../native-modules.js';
 import type { NavigationRoute } from '../navigation/route-names.js';
 import {
   composeTunnelbrokerQRAuthMessage,
   parseTunnelbrokerQRAuthMessage,
+  signDeviceListUpdate,
 } from '../qr-code/qr-code-utils.js';
 import { useStyles } from '../themes/colors.js';
 import Alert from '../utils/alert.js';
 
 const barCodeTypes = [BarCodeScanner.Constants.BarCodeType.qr];
 
 type Props = {
   +navigation: ProfileNavigationProp<'SecondaryDeviceQRCodeScanner'>,
   +route: NavigationRoute<'SecondaryDeviceQRCodeScanner'>,
 };
 // eslint-disable-next-line no-unused-vars
 function SecondaryDeviceQRCodeScanner(props: Props): React.Node {
   const [hasPermission, setHasPermission] = React.useState<?boolean>(null);
   const [scanned, setScanned] = React.useState(false);
 
   const styles = useStyles(unboundStyles);
   const navigation = useNavigation();
 
   const tunnelbrokerContext = useTunnelbroker();
   const identityContext = React.useContext(IdentityClientContext);
   invariant(identityContext, 'identity context not set');
 
   const aes256Key = React.useRef<?string>(null);
   const secondaryDeviceID = React.useRef<?string>(null);
 
   const broadcastDeviceListUpdate = React.useCallback(async () => {
     invariant(identityContext, 'identity context not set');
     const { getAuthMetadata, identityClient } = identityContext;
     const { userID } = await getAuthMetadata();
     if (!userID) {
       throw new Error('missing auth metadata');
     }
 
     const deviceLists =
       await identityClient.getDeviceListHistoryForUser(userID);
     invariant(deviceLists.length > 0, 'received empty device list history');
 
     const lastSignedDeviceList = deviceLists[deviceLists.length - 1];
     const deviceList: RawDeviceList = JSON.parse(
       lastSignedDeviceList.rawDeviceList,
     );
 
     const promises = deviceList.devices.map(recipient =>
       tunnelbrokerContext.sendMessage({
         deviceID: recipient,
         payload: JSON.stringify({
           type: peerToPeerMessageTypes.DEVICE_LIST_UPDATED,
           userID,
           signedDeviceList: lastSignedDeviceList,
         }),
       }),
     );
     await Promise.all(promises);
   }, [identityContext, tunnelbrokerContext]);
 
   const addDeviceToList = React.useCallback(
     async (newDeviceID: string) => {
       const { getDeviceListHistoryForUser, updateDeviceList } =
         identityContext.identityClient;
       invariant(
         updateDeviceList,
         'updateDeviceList() should be defined for primary device',
       );
 
       const authMetadata = await identityContext.getAuthMetadata();
       if (!authMetadata?.userID) {
         throw new Error('missing auth metadata');
       }
 
       const deviceLists = await getDeviceListHistoryForUser(
         authMetadata.userID,
       );
       invariant(deviceLists.length > 0, 'received empty device list history');
 
       const lastSignedDeviceList = deviceLists[deviceLists.length - 1];
       const deviceList: RawDeviceList = JSON.parse(
         lastSignedDeviceList.rawDeviceList,
       );
 
       const { devices } = deviceList;
       if (devices.includes(newDeviceID)) {
         return;
       }
 
       const newDeviceList: RawDeviceList = {
         devices: [...devices, newDeviceID],
         timestamp: Date.now(),
       };
-      await updateDeviceList({
-        rawDeviceList: JSON.stringify(newDeviceList),
-      });
+      const signedDeviceList = await signDeviceListUpdate(newDeviceList);
+      await updateDeviceList(signedDeviceList);
     },
     [identityContext],
   );
 
   const tunnelbrokerMessageListener = React.useCallback(
     async (message: TunnelbrokerMessage) => {
       const encryptionKey = aes256Key.current;
       const targetDeviceID = secondaryDeviceID.current;
       if (!encryptionKey || !targetDeviceID) {
         return;
       }
       if (message.type !== tunnelbrokerMessageTypes.MESSAGE_TO_DEVICE) {
         return;
       }
 
       let innerMessage: PeerToPeerMessage;
       try {
         innerMessage = JSON.parse(message.payload);
       } catch {
         return;
       }
       if (
         !peerToPeerMessageValidator.is(innerMessage) ||
         innerMessage.type !== peerToPeerMessageTypes.QR_CODE_AUTH_MESSAGE
       ) {
         return;
       }
 
       const payload = await parseTunnelbrokerQRAuthMessage(
         encryptionKey,
         innerMessage,
       );
       if (
         payload?.type !==
         qrCodeAuthMessageTypes.SECONDARY_DEVICE_REGISTRATION_SUCCESS
       ) {
         return;
       }
 
       void broadcastDeviceListUpdate();
 
       const backupSecret = await getBackupSecret();
       const backupKeysResponse =
         await commCoreModule.retrieveBackupKeys(backupSecret);
       const backupKeys = assertWithValidator<BackupKeys>(
         JSON.parse(backupKeysResponse),
         backupKeysValidator,
       );
 
       const backupKeyMessage = await composeTunnelbrokerQRAuthMessage(
         encryptionKey,
         {
           type: qrCodeAuthMessageTypes.BACKUP_DATA_KEY_MESSAGE,
           ...backupKeys,
         },
       );
       await tunnelbrokerContext.sendMessage({
         deviceID: targetDeviceID,
         payload: JSON.stringify(backupKeyMessage),
       });
 
       Alert.alert('Device added', 'Device registered successfully', [
         { text: 'OK' },
       ]);
     },
     [tunnelbrokerContext, broadcastDeviceListUpdate],
   );
 
   React.useEffect(() => {
     tunnelbrokerContext.addListener(tunnelbrokerMessageListener);
 
     return () => {
       tunnelbrokerContext.removeListener(tunnelbrokerMessageListener);
     };
   }, [tunnelbrokerMessageListener, tunnelbrokerContext]);
 
   React.useEffect(() => {
     void (async () => {
       const { status } = await BarCodeScanner.requestPermissionsAsync();
       setHasPermission(status === 'granted');
 
       if (status !== 'granted') {
         Alert.alert(
           'No access to camera',
           'Please allow Comm to access your camera in order to scan the QR code.',
           [{ text: 'OK' }],
         );
 
         navigation.goBack();
       }
     })();
   }, [navigation]);
 
   const onConnect = React.useCallback(
     async (barCodeEvent: BarCodeEvent) => {
       const { data } = barCodeEvent;
       const parsedData = parseDataFromDeepLink(data);
       const keysMatch = parsedData?.data?.keys;
 
       if (!parsedData || !keysMatch) {
         Alert.alert(
           'Scan failed',
           'QR code does not contain a valid pair of keys.',
           [{ text: 'OK' }],
         );
         return;
       }
 
       const keys = JSON.parse(decodeURIComponent(keysMatch));
       const { aes256, ed25519 } = keys;
       aes256Key.current = aes256;
       secondaryDeviceID.current = ed25519;
 
       try {
         const { deviceID: primaryDeviceID, userID } =
           await identityContext.getAuthMetadata();
         if (!primaryDeviceID || !userID) {
           throw new Error('missing auth metadata');
         }
         await addDeviceToList(ed25519);
         const message = await composeTunnelbrokerQRAuthMessage(aes256, {
           type: qrCodeAuthMessageTypes.DEVICE_LIST_UPDATE_SUCCESS,
           userID,
           primaryDeviceID,
         });
         await tunnelbrokerContext.sendMessage({
           deviceID: ed25519,
           payload: JSON.stringify(message),
         });
       } catch (err) {
         console.log('Primary device error:', err);
         Alert.alert(
           'Adding device failed',
           'Failed to update the device list',
           [{ text: 'OK' }],
         );
         navigation.goBack();
       }
     },
     [tunnelbrokerContext, addDeviceToList, identityContext, navigation],
   );
 
   const onCancelScan = React.useCallback(() => setScanned(false), []);
 
   const handleBarCodeScanned = React.useCallback(
     (barCodeEvent: BarCodeEvent) => {
       setScanned(true);
       Alert.alert(
         'Connect with this device?',
         'Are you sure you want to allow this device to log in to your account?',
         [
           {
             text: 'Cancel',
             style: 'cancel',
             onPress: onCancelScan,
           },
           {
             text: 'Connect',
             onPress: () => onConnect(barCodeEvent),
           },
         ],
         { cancelable: false },
       );
     },
     [onCancelScan, onConnect],
   );
 
   if (hasPermission === null) {
     return <View />;
   }
 
   // Note: According to the BarCodeScanner Expo docs, we should adhere to two
   // guidances when using the BarCodeScanner:
   // 1. We should specify the potential barCodeTypes we want to scan for to
   //    minimize battery usage.
   // 2. We should set the onBarCodeScanned callback to undefined if it scanned
   //    in order to 'pause' the scanner from continuing to scan while we
   //    process the data from the scan.
   // See: https://docs.expo.io/versions/latest/sdk/bar-code-scanner
   return (
     <View style={styles.container}>
       <BarCodeScanner
         onBarCodeScanned={scanned ? undefined : handleBarCodeScanned}
         barCodeTypes={barCodeTypes}
         style={styles.scanner}
       />
     </View>
   );
 }
 
 const unboundStyles = {
   container: {
     flex: 1,
     flexDirection: 'column',
     justifyContent: 'center',
   },
   scanner: {
     position: 'absolute',
     top: 0,
     left: 0,
     right: 0,
     bottom: 0,
   },
 };
 
 export default SecondaryDeviceQRCodeScanner;
diff --git a/native/qr-code/qr-code-utils.js b/native/qr-code/qr-code-utils.js
index c3833e6cc..1c0cc5f41 100644
--- a/native/qr-code/qr-code-utils.js
+++ b/native/qr-code/qr-code-utils.js
@@ -1,55 +1,86 @@
 // @flow
 
 import { hexToUintArray } from 'lib/media/data-utils.js';
+import type {
+  RawDeviceList,
+  SignedDeviceList,
+} from 'lib/types/identity-service-types.js';
 import {
   peerToPeerMessageTypes,
   type QRCodeAuthMessage,
 } from 'lib/types/tunnelbroker/peer-to-peer-message-types.js';
 import {
   qrCodeAuthMessagePayloadValidator,
   type QRCodeAuthMessagePayload,
 } from 'lib/types/tunnelbroker/qr-code-auth-message-types.js';
+import { getConfig } from 'lib/utils/config.js';
+import { getContentSigningKey } from 'lib/utils/crypto-utils.js';
 
 import {
   convertBytesToObj,
   convertObjToBytes,
 } from '../backup/conversion-utils.js';
 import { commUtilsModule } from '../native-modules.js';
 import * as AES from '../utils/aes-crypto-module.js';
 
 function composeTunnelbrokerQRAuthMessage(
   encryptionKey: string,
   obj: QRCodeAuthMessagePayload,
 ): Promise<QRCodeAuthMessage> {
   const objBytes = convertObjToBytes(obj);
   const keyBytes = hexToUintArray(encryptionKey);
   const encryptedBytes = AES.encrypt(keyBytes, objBytes);
   const encryptedContent = commUtilsModule.base64EncodeBuffer(
     encryptedBytes.buffer,
   );
   return Promise.resolve({
     type: peerToPeerMessageTypes.QR_CODE_AUTH_MESSAGE,
     encryptedContent,
   });
 }
 
 function parseTunnelbrokerQRAuthMessage(
   encryptionKey: string,
   message: QRCodeAuthMessage,
 ): Promise<?QRCodeAuthMessagePayload> {
   const encryptedData = commUtilsModule.base64DecodeBuffer(
     message.encryptedContent,
   );
   const decryptedData = AES.decrypt(
     hexToUintArray(encryptionKey),
     new Uint8Array(encryptedData),
   );
   const payload = convertBytesToObj<QRCodeAuthMessagePayload>(decryptedData);
   if (!qrCodeAuthMessagePayloadValidator.is(payload)) {
     return Promise.resolve(null);
   }
 
   return Promise.resolve(payload);
 }
 
-export { composeTunnelbrokerQRAuthMessage, parseTunnelbrokerQRAuthMessage };
+async function signDeviceListUpdate(
+  deviceListPayload: RawDeviceList,
+): Promise<SignedDeviceList> {
+  const deviceID = await getContentSigningKey();
+  const rawDeviceList = JSON.stringify(deviceListPayload);
+
+  // don't sign device list if current device is not a primary one
+  if (deviceListPayload.devices[0] !== deviceID) {
+    return {
+      rawDeviceList,
+    };
+  }
+
+  const { olmAPI } = getConfig();
+  const curPrimarySignature = await olmAPI.signMessage(rawDeviceList);
+  return {
+    rawDeviceList,
+    curPrimarySignature,
+  };
+}
+
+export {
+  composeTunnelbrokerQRAuthMessage,
+  parseTunnelbrokerQRAuthMessage,
+  signDeviceListUpdate,
+};