diff --git a/lib/types/tunnelbroker/peer-to-peer-message-types.js b/lib/types/tunnelbroker/peer-to-peer-message-types.js
index 6e63d3412..34195634a 100644
--- a/lib/types/tunnelbroker/peer-to-peer-message-types.js
+++ b/lib/types/tunnelbroker/peer-to-peer-message-types.js
@@ -1,81 +1,100 @@
 // @flow
 
 import type { TInterface, TUnion } from 'tcomb';
 import t from 'tcomb';
 
 import { tShape, tString } from '../../utils/validation-utils.js';
+import {
+  signedDeviceListValidator,
+  type SignedDeviceList,
+} from '../identity-service-types.js';
 
 export type SenderInfo = {
   +userID: string,
   +deviceID: string,
 };
 const senderInfoValidator: TInterface<SenderInfo> = tShape<SenderInfo>({
   userID: t.String,
   deviceID: t.String,
 });
 
 export const peerToPeerMessageTypes = Object.freeze({
   OUTBOUND_SESSION_CREATION: 'OutboundSessionCreation',
   ENCRYPTED_MESSAGE: 'EncryptedMessage',
   REFRESH_KEY_REQUEST: 'RefreshKeyRequest',
   QR_CODE_AUTH_MESSAGE: 'QRCodeAuthMessage',
+  DEVICE_LIST_UPDATED: 'DeviceListUpdated',
 });
 
 export type OutboundSessionCreation = {
   +type: 'OutboundSessionCreation',
   +senderInfo: SenderInfo,
   +encryptedContent: string,
 };
 export const outboundSessionCreationValidator: TInterface<OutboundSessionCreation> =
   tShape<OutboundSessionCreation>({
     type: tString(peerToPeerMessageTypes.OUTBOUND_SESSION_CREATION),
     senderInfo: senderInfoValidator,
     encryptedContent: t.String,
   });
 
 export type EncryptedMessage = {
   +type: 'EncryptedMessage',
   +senderInfo: SenderInfo,
   +encryptedContent: string,
 };
 export const encryptedMessageValidator: TInterface<EncryptedMessage> =
   tShape<EncryptedMessage>({
     type: tString(peerToPeerMessageTypes.ENCRYPTED_MESSAGE),
     senderInfo: senderInfoValidator,
     encryptedContent: t.String,
   });
 
 export type RefreshKeyRequest = {
   +type: 'RefreshKeyRequest',
   +deviceID: string,
   +numberOfKeys: number,
 };
 export const refreshKeysRequestValidator: TInterface<RefreshKeyRequest> =
   tShape<RefreshKeyRequest>({
     type: tString(peerToPeerMessageTypes.REFRESH_KEY_REQUEST),
     deviceID: t.String,
     numberOfKeys: t.Number,
   });
 
 export type QRCodeAuthMessage = {
   +type: 'QRCodeAuthMessage',
   +encryptedContent: string,
 };
 export const qrCodeAuthMessageValidator: TInterface<QRCodeAuthMessage> =
   tShape<QRCodeAuthMessage>({
     type: tString(peerToPeerMessageTypes.QR_CODE_AUTH_MESSAGE),
     encryptedContent: t.String,
   });
 
+export type DeviceListUpdated = {
+  +type: 'DeviceListUpdated',
+  +userID: string,
+  +signedDeviceList: SignedDeviceList,
+};
+export const deviceListUpdatedValidator: TInterface<DeviceListUpdated> =
+  tShape<DeviceListUpdated>({
+    type: tString(peerToPeerMessageTypes.DEVICE_LIST_UPDATED),
+    userID: t.String,
+    signedDeviceList: signedDeviceListValidator,
+  });
+
 export type PeerToPeerMessage =
   | OutboundSessionCreation
   | EncryptedMessage
   | RefreshKeyRequest
-  | QRCodeAuthMessage;
+  | QRCodeAuthMessage
+  | DeviceListUpdated;
 
 export const peerToPeerMessageValidator: TUnion<PeerToPeerMessage> = t.union([
   outboundSessionCreationValidator,
   encryptedMessageValidator,
   refreshKeysRequestValidator,
   qrCodeAuthMessageValidator,
+  deviceListUpdatedValidator,
 ]);
diff --git a/native/profile/secondary-device-qr-code-scanner.react.js b/native/profile/secondary-device-qr-code-scanner.react.js
index 058089aa1..fa13572a5 100644
--- a/native/profile/secondary-device-qr-code-scanner.react.js
+++ b/native/profile/secondary-device-qr-code-scanner.react.js
@@ -1,272 +1,316 @@
 // @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 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 {
   createQRAuthTunnelbrokerMessage,
   parseQRAuthTunnelbrokerMessage,
 } from 'lib/utils/qr-code-auth.js';
 
 import type { ProfileNavigationProp } from './profile.react.js';
 import type { NavigationRoute } from '../navigation/route-names.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),
       });
     },
     [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 = parseQRAuthTunnelbrokerMessage(
         encryptionKey,
         innerMessage,
       );
       if (
         payload?.type !==
         qrCodeAuthMessageTypes.SECONDARY_DEVICE_REGISTRATION_SUCCESS
       ) {
         return;
       }
+
+      void broadcastDeviceListUpdate();
+
+      const backupKeyMessage = createQRAuthTunnelbrokerMessage(encryptionKey, {
+        type: qrCodeAuthMessageTypes.BACKUP_DATA_KEY_MESSAGE,
+        backupID: 'stub',
+        backupDataKey: 'stub',
+        backupLogDataKey: 'stub',
+      });
+      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 = createQRAuthTunnelbrokerMessage(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-screen.react.js b/native/qr-code/qr-code-screen.react.js
index f8c59b5ac..8c70acafc 100644
--- a/native/qr-code/qr-code-screen.react.js
+++ b/native/qr-code/qr-code-screen.react.js
@@ -1,253 +1,262 @@
 // @flow
 
 import invariant from 'invariant';
 import * as React from 'react';
 import { View, Text } from 'react-native';
 import QRCode from 'react-native-qrcode-svg';
 
 import { qrCodeLinkURL } from 'lib/facts/links.js';
 import { uintArrayToHexString } from 'lib/media/data-utils.js';
 import { IdentityClientContext } from 'lib/shared/identity-client-context.js';
 import { useTunnelbroker } from 'lib/tunnelbroker/tunnelbroker-context.js';
 import type {
   NonceChallenge,
   SignedMessage,
 } from 'lib/types/identity-service-types.js';
 import {
   tunnelbrokerMessageTypes,
   type TunnelbrokerMessage,
 } from 'lib/types/tunnelbroker/messages.js';
 import {
   peerToPeerMessageTypes,
   peerToPeerMessageValidator,
 } from 'lib/types/tunnelbroker/peer-to-peer-message-types.js';
 import { qrCodeAuthMessageTypes } from 'lib/types/tunnelbroker/qr-code-auth-message-types.js';
 import {
   createQRAuthTunnelbrokerMessage,
   parseQRAuthTunnelbrokerMessage,
 } from 'lib/utils/qr-code-auth.js';
 
 import type { QRCodeSignInNavigationProp } from './qr-code-sign-in-navigator.react.js';
 import { commCoreModule } from '../native-modules.js';
 import type { NavigationRoute } from '../navigation/route-names.js';
 import { useStyles } from '../themes/colors.js';
 import * as AES from '../utils/aes-crypto-module.js';
 import Alert from '../utils/alert.js';
 import { getContentSigningKey } from '../utils/crypto-utils.js';
 
 type QRCodeScreenProps = {
   +navigation: QRCodeSignInNavigationProp<'QRCodeScreen'>,
   +route: NavigationRoute<'QRCodeScreen'>,
 };
 
 // eslint-disable-next-line no-unused-vars
 function QRCodeScreen(props: QRCodeScreenProps): React.Node {
   const [qrCodeValue, setQrCodeValue] = React.useState<?string>();
   const [qrData, setQRData] =
     React.useState<?{ +deviceID: string, +aesKey: string }>();
   const [primaryDeviceID, setPrimaryDeviceID] = React.useState<?string>();
   const {
     setUnauthorizedDeviceID,
     addListener,
     removeListener,
     connected: tunnelbrokerConnected,
     isAuthorized,
     sendMessage,
   } = useTunnelbroker();
   const identityContext = React.useContext(IdentityClientContext);
   const identityClient = identityContext?.identityClient;
 
   React.useEffect(() => {
     if (
       !tunnelbrokerConnected ||
       !isAuthorized ||
       !primaryDeviceID ||
       !qrData
     ) {
       return;
     }
 
     const message = createQRAuthTunnelbrokerMessage(qrData.aesKey, {
       type: qrCodeAuthMessageTypes.SECONDARY_DEVICE_REGISTRATION_SUCCESS,
     });
     void sendMessage({
       deviceID: primaryDeviceID,
       payload: JSON.stringify(message),
     });
   }, [
     tunnelbrokerConnected,
     isAuthorized,
     sendMessage,
     primaryDeviceID,
     qrData,
   ]);
 
   const tunnelbrokerMessageListener = React.useCallback(
     async (message: TunnelbrokerMessage) => {
       invariant(identityClient, 'identity context not set');
       if (
         !qrData ||
         message.type !== tunnelbrokerMessageTypes.MESSAGE_TO_DEVICE
       ) {
         return;
       }
 
       let innerMessage;
       try {
         innerMessage = JSON.parse(message.payload);
       } catch {
         return;
       }
       if (
         !peerToPeerMessageValidator.is(innerMessage) ||
         innerMessage.type !== peerToPeerMessageTypes.QR_CODE_AUTH_MESSAGE
       ) {
         return;
       }
       const qrCodeAuthMessage = parseQRAuthTunnelbrokerMessage(
         qrData.aesKey,
         innerMessage,
       );
+
+      if (
+        qrCodeAuthMessage?.type ===
+        qrCodeAuthMessageTypes.BACKUP_DATA_KEY_MESSAGE
+      ) {
+        console.log('Received backup data key:', qrCodeAuthMessage);
+        return;
+      }
+
       if (
         !qrCodeAuthMessage ||
         qrCodeAuthMessage.type !==
           qrCodeAuthMessageTypes.DEVICE_LIST_UPDATE_SUCCESS
       ) {
         return;
       }
       const { primaryDeviceID: receivedPrimaryDeviceID, userID } =
         qrCodeAuthMessage;
       setPrimaryDeviceID(receivedPrimaryDeviceID);
 
       try {
         const nonce = await identityClient.generateNonce();
         const nonceChallenge: NonceChallenge = { nonce };
         const nonceMessage = JSON.stringify(nonceChallenge);
         const signature = await commCoreModule.signMessage(nonceMessage);
         const challengeResponse: SignedMessage = {
           message: nonceMessage,
           signature,
         };
 
         await identityClient.uploadKeysForRegisteredDeviceAndLogIn(
           userID,
           challengeResponse,
         );
         setUnauthorizedDeviceID(null);
       } catch (err) {
         console.error('Secondary device registration error:', err);
         Alert.alert('Registration failed', 'Failed to upload device keys', [
           { text: 'OK' },
         ]);
       }
     },
     [setUnauthorizedDeviceID, identityClient, qrData],
   );
 
   React.useEffect(() => {
     if (!qrData) {
       return undefined;
     }
     addListener(tunnelbrokerMessageListener);
     setUnauthorizedDeviceID(qrData.deviceID);
 
     return () => {
       removeListener(tunnelbrokerMessageListener);
       setUnauthorizedDeviceID(null);
     };
   }, [
     setUnauthorizedDeviceID,
     qrData,
     addListener,
     removeListener,
     tunnelbrokerMessageListener,
   ]);
 
   const generateQRCode = React.useCallback(async () => {
     try {
       const rawAESKey: Uint8Array = await AES.generateKey();
       const aesKeyAsHexString: string = uintArrayToHexString(rawAESKey);
 
       const ed25519Key: string = await getContentSigningKey();
 
       const url = qrCodeLinkURL(aesKeyAsHexString, ed25519Key);
       setQrCodeValue(url);
       setQRData({ deviceID: ed25519Key, aesKey: aesKeyAsHexString });
     } catch (err) {
       console.error('Failed to generate QR Code:', err);
     }
   }, []);
 
   React.useEffect(() => {
     void generateQRCode();
   }, [generateQRCode]);
 
   const styles = useStyles(unboundStyles);
   return (
     <View style={styles.container}>
       <Text style={styles.heading}>Log in to Comm</Text>
       <Text style={styles.headingSubtext}>
         Open the Comm app on your phone and scan the QR code below
       </Text>
       <QRCode value={qrCodeValue} size={200} />
       <View style={styles.instructionsBox}>
         <Text style={styles.instructionsTitle}>How to find the scanner:</Text>
         <Text style={styles.instructionsStep}>
           <Text>Go to </Text>
           <Text style={styles.instructionsBold}>Profile</Text>
         </Text>
         <Text style={styles.instructionsStep}>
           <Text>Select </Text>
           <Text style={styles.instructionsBold}>Linked devices </Text>
         </Text>
         <Text style={styles.instructionsStep}>
           <Text>Click </Text>
           <Text style={styles.instructionsBold}>Add </Text>
           <Text>on the top right</Text>
         </Text>
       </View>
     </View>
   );
 }
 
 const unboundStyles = {
   container: {
     flex: 1,
     alignItems: 'center',
     marginTop: 125,
   },
   heading: {
     fontSize: 24,
     color: 'panelForegroundLabel',
     paddingBottom: 12,
   },
   headingSubtext: {
     fontSize: 12,
     color: 'panelForegroundLabel',
     paddingBottom: 30,
   },
   instructionsBox: {
     alignItems: 'center',
     width: 300,
     marginTop: 40,
     padding: 15,
     borderColor: 'panelForegroundLabel',
     borderWidth: 2,
     borderRadius: 8,
   },
   instructionsTitle: {
     fontSize: 12,
     color: 'panelForegroundLabel',
     paddingBottom: 15,
   },
   instructionsStep: {
     fontSize: 12,
     padding: 1,
     color: 'panelForegroundLabel',
   },
   instructionsBold: {
     fontWeight: 'bold',
   },
 };
 
 export default QRCodeScreen;