diff --git a/integration_test/test_res/.gitignore b/integration_test/test_res/.gitignore
new file mode 100644
index 00000000..8fd64062
--- /dev/null
+++ b/integration_test/test_res/.gitignore
@@ -0,0 +1,3 @@
+/pubspec.lock
+/.dart_tool
+
diff --git a/integration_test/test_res/pubspec.yaml b/integration_test/test_res/pubspec.yaml
new file mode 100644
index 00000000..a5fc9916
--- /dev/null
+++ b/integration_test/test_res/pubspec.yaml
@@ -0,0 +1,6 @@
+name: test_res
+environment:
+  sdk: '>=3.0.0 <4.0.0'
+flutter:
+  assets:
+    - resources/
diff --git a/integration_test/test_res/resources/.gitignore b/integration_test/test_res/resources/.gitignore
new file mode 100644
index 00000000..1dc84162
--- /dev/null
+++ b/integration_test/test_res/resources/.gitignore
@@ -0,0 +1 @@
+approved_serial_numbers.csv
diff --git a/integration_test/utils/test_util.dart b/integration_test/utils/test_util.dart
index 449556b2..9641d189 100644
--- a/integration_test/utils/test_util.dart
+++ b/integration_test/utils/test_util.dart
@@ -15,6 +15,7 @@
  */
 
 import 'package:flutter/material.dart';
+import 'package:flutter/services.dart' show rootBundle;
 import 'package:flutter_test/flutter_test.dart';
 import 'package:freezed_annotation/freezed_annotation.dart';
 import 'package:yubico_authenticator/app/views/keys.dart' as app_keys;
@@ -113,28 +114,42 @@ extension AppWidgetTester on WidgetTester {
     expect(find.byKey(screenKey), findsOneWidget);
   }
 
-  Future<void> startUp([Map<dynamic, dynamic> startUpParams = const {}]) async {
-    // YA_TEST_APPROVED_KEY_SN should contain comma separated list of
-    // YubiKey serial numbers which are approved for tests
-    // To pass the variable to the test use:
-    // flutter --dart-define=YA_TEST_APPROVED_KEY_SN=SN1,SN2,...,SNn test t
-    const envVar = String.fromEnvironment('YA_TEST_APPROVED_KEY_SN');
-    final approvedSerialNumbers = envVar.split(',');
+  /// Retrieve a list of test approved serial numbers.
+  ///
+  /// To add testing keys add comma separated serial numbers to a file
+  /// `approved_serial_numbers.csv` in `integration_test/test_res/resources/`.
+  /// This file is bundled only during test runs and is explicitly ignored from
+  /// version control.
+  Future<List<String>> getApprovedSerialNumbers() async {
+    const approvedKeysResource = 'approved_serial_numbers.csv';
+    String approved = '';
 
+    try {
+      approved = await rootBundle.loadString(
+        'packages/test_res/resources/$approvedKeysResource',
+      );
+    } catch (_) {
+      testLog(false, 'Failed to read $approvedKeysResource');
+    }
+
+    return approved.split(',').map((e) => e.trim()).toList(growable: false);
+  }
+
+  Future<void> startUp([Map<dynamic, dynamic> startUpParams = const {}]) async {
     var result = isAndroid == true
         ? await android_test_util.startUp(this, startUpParams)
         : await desktop_test_util.startUp(this, startUpParams);
 
     await collectYubiKeyInformation();
 
-    if (!approvedSerialNumbers.contains(yubiKeySerialNumber)) {
+    final approved = await getApprovedSerialNumbers();
+
+    if (!approved.contains(yubiKeySerialNumber)) {
       if (yubiKeySerialNumber == null) {
-        expect(
-            approvedSerialNumbers.contains(yubiKeySerialNumber), equals(true),
+        expect(approved.contains(yubiKeySerialNumber), equals(true),
             reason: 'No YubiKey connected');
       } else {
-        expect(
-            approvedSerialNumbers.contains(yubiKeySerialNumber), equals(true),
+        expect(approved.contains(yubiKeySerialNumber), equals(true),
             reason:
                 'YubiKey with S/N $yubiKeySerialNumber is not approved for integration tests.');
       }
diff --git a/pubspec.lock b/pubspec.lock
index aa2e3685..0a6be582 100644
--- a/pubspec.lock
+++ b/pubspec.lock
@@ -792,6 +792,13 @@ packages:
       url: "https://pub.dev"
     source: hosted
     version: "0.6.0"
+  test_res:
+    dependency: "direct dev"
+    description:
+      path: "integration_test/test_res"
+      relative: true
+    source: path
+    version: "0.0.0"
   timing:
     dependency: transitive
     description:
diff --git a/pubspec.yaml b/pubspec.yaml
index 4aabb6fa..f4d7f0e6 100644
--- a/pubspec.yaml
+++ b/pubspec.yaml
@@ -73,6 +73,8 @@ dev_dependencies:
     sdk: flutter
   flutter_test:
     sdk: flutter
+  test_res:
+    path: integration_test/test_res
 
   # The "flutter_lints" package below contains a set of recommended lints to
   # encourage good coding practices. The lint set provided by the package is