diff --git a/lib/facts/links.js b/lib/facts/links.js
--- a/lib/facts/links.js
+++ b/lib/facts/links.js
@@ -6,7 +6,7 @@
 }
 
 /* QR Code */
-function qrCodeLinkUrl(aes256Param: string, ed25519Param: string): string {
+function qrCodeLinkUrl(aes256Param: Uint8Array, ed25519Param: string): string {
   const keys = {
     aes256: aes256Param,
     ed25519: ed25519Param,
diff --git a/native/qr-code/qr-code-screen.react.js b/native/qr-code/qr-code-screen.react.js
--- a/native/qr-code/qr-code-screen.react.js
+++ b/native/qr-code/qr-code-screen.react.js
@@ -9,16 +9,27 @@
 import type { QRCodeSignInNavigationProp } from './qr-code-sign-in-navigator.react.js';
 import type { NavigationRoute } from '../navigation/route-names.js';
 import { useStyles } from '../themes/colors.js';
+import * as AES from '../utils/aes-crypto-module.js';
 
 type QRCodeScreenProps = {
   +navigation: QRCodeSignInNavigationProp<'QRCodeScreen'>,
   +route: NavigationRoute<'QRCodeScreen'>,
 };
 
-const qrCodeValue = qrCodeLinkUrl('random_aes256_key', 'device_ed25519_key');
+const defaultDeviceEd25519Key = 'device_ed25519_key';
 
 // eslint-disable-next-line no-unused-vars
 function QRCodeScreen(props: QRCodeScreenProps): React.Node {
+  const [qrCodeValue, setQrCodeValue] = React.useState<?string>();
+
+  React.useEffect(() => {
+    (async () => {
+      const aes256Key: Uint8Array = await AES.generateKey();
+      const url = qrCodeLinkUrl(aes256Key, defaultDeviceEd25519Key);
+      setQrCodeValue(url);
+    })();
+  }, []);
+
   const styles = useStyles(unboundStyles);
   return (
     <View style={styles.container}>
diff --git a/web/account/qr-code-login.react.js b/web/account/qr-code-login.react.js
--- a/web/account/qr-code-login.react.js
+++ b/web/account/qr-code-login.react.js
@@ -6,10 +6,21 @@
 import { qrCodeLinkUrl } from 'lib/facts/links.js';
 
 import css from './qr-code-login.css';
+import { generateKey } from '../media/aes-crypto-utils.js';
 
-const qrCodeValue = qrCodeLinkUrl('random_aes256_key', 'device_ed25519_key');
+const defaultDeviceEd25519Key = 'device_ed25519_key';
 
 function QrCodeLogin(): React.Node {
+  const [qrCodeValue, setQrCodeValue] = React.useState<?string>();
+
+  React.useEffect(() => {
+    (async () => {
+      const aes256Key: Uint8Array = await generateKey();
+      const url = qrCodeLinkUrl(aes256Key, defaultDeviceEd25519Key);
+      setQrCodeValue(url);
+    })();
+  }, []);
+
   return (
     <div className={css.qrContainer}>
       <div className={css.title}>Log in to Comm</div>