diff --git a/services/core/java/com/android/server/notification/NotificationManagerService.java b/services/core/java/com/android/server/notification/NotificationManagerService.java
index 33e9af9..fd717cc 100755
--- a/services/core/java/com/android/server/notification/NotificationManagerService.java
+++ b/services/core/java/com/android/server/notification/NotificationManagerService.java
@@ -245,6 +245,7 @@
 import android.util.Pair;
 import android.util.Slog;
 import android.util.SparseArray;
+import android.util.SparseBooleanArray;
 import android.util.StatsEvent;
 import android.util.TypedXmlPullParser;
 import android.util.TypedXmlSerializer;
@@ -277,6 +278,7 @@
 import com.android.internal.util.Preconditions;
 import com.android.internal.util.XmlUtils;
 import com.android.internal.util.function.TriPredicate;
+import com.android.internal.widget.LockPatternUtils;
 import com.android.server.DeviceIdleInternal;
 import com.android.server.EventLogTags;
 import com.android.server.IoThread;
@@ -1998,6 +2000,54 @@
     private SettingsObserver mSettingsObserver;
     protected ZenModeHelper mZenModeHelper;
 
+    protected class StrongAuthTracker extends LockPatternUtils.StrongAuthTracker {
+
+        SparseBooleanArray mUserInLockDownMode = new SparseBooleanArray();
+        boolean mIsInLockDownMode = false;
+
+        StrongAuthTracker(Context context) {
+            super(context);
+        }
+
+        private boolean containsFlag(int haystack, int needle) {
+            return (haystack & needle) != 0;
+        }
+
+        public boolean isInLockDownMode() {
+            return mIsInLockDownMode;
+        }
+
+        @Override
+        public synchronized void onStrongAuthRequiredChanged(int userId) {
+            boolean userInLockDownModeNext = containsFlag(getStrongAuthForUser(userId),
+                    STRONG_AUTH_REQUIRED_AFTER_USER_LOCKDOWN);
+            mUserInLockDownMode.put(userId, userInLockDownModeNext);
+            boolean isInLockDownModeNext = mUserInLockDownMode.indexOfValue(true) != -1;
+
+            if (mIsInLockDownMode == isInLockDownModeNext) {
+                return;
+            }
+
+            if (isInLockDownModeNext) {
+                cancelNotificationsWhenEnterLockDownMode();
+            }
+
+            // When the mIsInLockDownMode is true, both notifyPostedLocked and
+            // notifyRemovedLocked will be dismissed. So we shall call
+            // cancelNotificationsWhenEnterLockDownMode before we set mIsInLockDownMode
+            // as true and call postNotificationsWhenExitLockDownMode after we set
+            // mIsInLockDownMode as false.
+            mIsInLockDownMode = isInLockDownModeNext;
+
+            if (!isInLockDownModeNext) {
+                postNotificationsWhenExitLockDownMode();
+            }
+        }
+    }
+
+    private LockPatternUtils mLockPatternUtils;
+    private StrongAuthTracker mStrongAuthTracker;
+
     public NotificationManagerService(Context context) {
         this(context,
                 new NotificationRecordLoggerImpl(),
@@ -2021,6 +2071,11 @@
     }
 
     @VisibleForTesting
+    void setStrongAuthTracker(StrongAuthTracker strongAuthTracker) {
+        mStrongAuthTracker = strongAuthTracker;
+    }
+
+    @VisibleForTesting
     void setKeyguardManager(KeyguardManager keyguardManager) {
         mKeyguardManager = keyguardManager;
     }
@@ -2207,6 +2262,8 @@
                 ServiceManager.getService(Context.PLATFORM_COMPAT_SERVICE));
 
         mUiHandler = new Handler(UiThread.get().getLooper());
+        mLockPatternUtils = new LockPatternUtils(getContext());
+        mStrongAuthTracker = new StrongAuthTracker(getContext());
         String[] extractorNames;
         try {
             extractorNames = resources.getStringArray(R.array.config_notificationSignalExtractors);
@@ -2689,6 +2746,7 @@
                 bubbsExtractor.setShortcutHelper(mShortcutHelper);
             }
             registerNotificationPreferencesPullers();
+            mLockPatternUtils.registerStrongAuthTracker(mStrongAuthTracker);
         } else if (phase == SystemService.PHASE_THIRD_PARTY_APPS_CAN_START) {
             // This observer will force an update when observe is called, causing us to
             // bind to listener services.
@@ -9105,6 +9163,29 @@
         }
     }
 
+    private void cancelNotificationsWhenEnterLockDownMode() {
+        synchronized (mNotificationLock) {
+            int numNotifications = mNotificationList.size();
+            for (int i = 0; i < numNotifications; i++) {
+                NotificationRecord rec = mNotificationList.get(i);
+                mListeners.notifyRemovedLocked(rec, REASON_CANCEL_ALL,
+                        rec.getStats());
+            }
+
+        }
+    }
+
+    private void postNotificationsWhenExitLockDownMode() {
+        synchronized (mNotificationLock) {
+            int numNotifications = mNotificationList.size();
+            for (int i = 0; i < numNotifications; i++) {
+                NotificationRecord rec = mNotificationList.get(i);
+                mListeners.notifyPostedLocked(rec, rec);
+            }
+
+        }
+    }
+
     private void updateNotificationPulse() {
         synchronized (mNotificationLock) {
             updateLightsLocked();
@@ -9340,6 +9421,10 @@
                 rankings.toArray(new NotificationListenerService.Ranking[0]));
     }
 
+    boolean isInLockDownMode() {
+        return mStrongAuthTracker.isInLockDownMode();
+    }
+
     boolean hasCompanionDevice(ManagedServiceInfo info) {
         if (mCompanionManager == null) {
             mCompanionManager = getCompanionManager();
@@ -10391,8 +10476,12 @@
          *                           targetting <= O_MR1
          */
         @GuardedBy("mNotificationLock")
-        private void notifyPostedLocked(NotificationRecord r, NotificationRecord old,
+        void notifyPostedLocked(NotificationRecord r, NotificationRecord old,
                 boolean notifyAllListeners) {
+            if (isInLockDownMode()) {
+                return;
+            }
+
             try {
                 // Lazily initialized snapshots of the notification.
                 StatusBarNotification sbn = r.getSbn();
@@ -10490,6 +10579,10 @@
         @GuardedBy("mNotificationLock")
         public void notifyRemovedLocked(NotificationRecord r, int reason,
                 NotificationStats notificationStats) {
+            if (isInLockDownMode()) {
+                return;
+            }
+
             final StatusBarNotification sbn = r.getSbn();
 
             // make a copy in case changes are made to the underlying Notification object
@@ -10535,6 +10628,10 @@
          */
         @GuardedBy("mNotificationLock")
         public void notifyRankingUpdateLocked(List<NotificationRecord> changedHiddenNotifications) {
+            if (isInLockDownMode()) {
+                return;
+            }
+
             boolean isHiddenRankingUpdate = changedHiddenNotifications != null
                     && changedHiddenNotifications.size() > 0;
             // TODO (b/73052211): if the ranking update changed the notification type,
diff --git a/services/tests/uiservicestests/AndroidManifest.xml b/services/tests/uiservicestests/AndroidManifest.xml
index 767857b..e8e3a8f 100644
--- a/services/tests/uiservicestests/AndroidManifest.xml
+++ b/services/tests/uiservicestests/AndroidManifest.xml
@@ -33,6 +33,7 @@
     <uses-permission android:name="android.permission.OBSERVE_ROLE_HOLDERS" />
     <uses-permission android:name="android.permission.GET_INTENT_SENDER_INTENT"/>
     <uses-permission android:name="android.permission.WRITE_DEVICE_CONFIG" />
+    <uses-permission android:name="android.permission.ACCESS_KEYGUARD_SECURE_STORAGE" />
 
     <application android:debuggable="true">
         <uses-library android:name="android.test.runner" />
diff --git a/services/tests/uiservicestests/src/com/android/server/notification/NotificationListenersTest.java b/services/tests/uiservicestests/src/com/android/server/notification/NotificationListenersTest.java
index 50ebffc..313f307 100644
--- a/services/tests/uiservicestests/src/com/android/server/notification/NotificationListenersTest.java
+++ b/services/tests/uiservicestests/src/com/android/server/notification/NotificationListenersTest.java
@@ -24,10 +24,12 @@
 
 import static com.google.common.truth.Truth.assertThat;
 
-import static org.mockito.ArgumentMatchers.any;
-import static org.mockito.ArgumentMatchers.anyInt;
+import static org.mockito.Mockito.atLeast;
 import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.never;
+import static org.mockito.Mockito.reset;
 import static org.mockito.Mockito.spy;
+import static org.mockito.Mockito.verify;
 import static org.mockito.Mockito.when;
 
 import android.app.INotificationManager;
@@ -39,9 +41,10 @@
 import android.os.Bundle;
 import android.service.notification.NotificationListenerFilter;
 import android.service.notification.NotificationListenerService;
+import android.service.notification.NotificationStats;
+import android.service.notification.StatusBarNotification;
 import android.util.ArraySet;
 import android.util.Pair;
-import android.util.Slog;
 import android.util.TypedXmlPullParser;
 import android.util.TypedXmlSerializer;
 import android.util.Xml;
@@ -52,11 +55,13 @@
 import org.junit.Test;
 import org.mockito.Mock;
 import org.mockito.MockitoAnnotations;
+import org.mockito.internal.util.reflection.FieldSetter;
 
 import java.io.BufferedInputStream;
 import java.io.BufferedOutputStream;
 import java.io.ByteArrayInputStream;
 import java.io.ByteArrayOutputStream;
+import java.util.List;
 
 public class NotificationListenersTest extends UiServiceTestCase {
 
@@ -355,4 +360,65 @@
                 .getDisallowedPackages()).isEmpty();
     }
 
+    @Test
+    public void testNotifyPostedLockedInLockdownMode() {
+        NotificationRecord r = mock(NotificationRecord.class);
+        NotificationRecord old = mock(NotificationRecord.class);
+
+        // before the lockdown mode
+        when(mNm.isInLockDownMode()).thenReturn(false);
+        mListeners.notifyPostedLocked(r, old, true);
+        mListeners.notifyPostedLocked(r, old, false);
+        verify(r, atLeast(2)).getSbn();
+
+        // in the lockdown mode
+        reset(r);
+        reset(old);
+        when(mNm.isInLockDownMode()).thenReturn(true);
+        mListeners.notifyPostedLocked(r, old, true);
+        mListeners.notifyPostedLocked(r, old, false);
+        verify(r, never()).getSbn();
+    }
+
+    @Test
+    public void testnotifyRankingUpdateLockedInLockdownMode() {
+        List chn = mock(List.class);
+
+        // before the lockdown mode
+        when(mNm.isInLockDownMode()).thenReturn(false);
+        mListeners.notifyRankingUpdateLocked(chn);
+        verify(chn, atLeast(1)).size();
+
+        // in the lockdown mode
+        reset(chn);
+        when(mNm.isInLockDownMode()).thenReturn(true);
+        mListeners.notifyRankingUpdateLocked(chn);
+        verify(chn, never()).size();
+    }
+
+    @Test
+    public void testNotifyRemovedLockedInLockdownMode() throws NoSuchFieldException {
+        NotificationRecord r = mock(NotificationRecord.class);
+        NotificationStats rs = mock(NotificationStats.class);
+        StatusBarNotification sbn = mock(StatusBarNotification.class);
+        FieldSetter.setField(mNm,
+                NotificationManagerService.class.getDeclaredField("mHandler"),
+                mock(NotificationManagerService.WorkerHandler.class));
+
+        // before the lockdown mode
+        when(mNm.isInLockDownMode()).thenReturn(false);
+        when(r.getSbn()).thenReturn(sbn);
+        mListeners.notifyRemovedLocked(r, 0, rs);
+        mListeners.notifyRemovedLocked(r, 0, rs);
+        verify(r, atLeast(2)).getSbn();
+
+        // in the lockdown mode
+        reset(r);
+        reset(rs);
+        when(mNm.isInLockDownMode()).thenReturn(true);
+        when(r.getSbn()).thenReturn(sbn);
+        mListeners.notifyRemovedLocked(r, 0, rs);
+        mListeners.notifyRemovedLocked(r, 0, rs);
+        verify(r, never()).getSbn();
+    }
 }
diff --git a/services/tests/uiservicestests/src/com/android/server/notification/NotificationManagerServiceTest.java b/services/tests/uiservicestests/src/com/android/server/notification/NotificationManagerServiceTest.java
index e8e08bf..464b7635 100755
--- a/services/tests/uiservicestests/src/com/android/server/notification/NotificationManagerServiceTest.java
+++ b/services/tests/uiservicestests/src/com/android/server/notification/NotificationManagerServiceTest.java
@@ -58,9 +58,11 @@
 import static android.service.notification.NotificationListenerService.FLAG_FILTER_TYPE_ALERTING;
 import static android.service.notification.NotificationListenerService.FLAG_FILTER_TYPE_CONVERSATIONS;
 import static android.service.notification.NotificationListenerService.FLAG_FILTER_TYPE_ONGOING;
+import static android.service.notification.NotificationListenerService.REASON_CANCEL_ALL;
 import static android.service.notification.NotificationListenerService.Ranking.USER_SENTIMENT_NEGATIVE;
 import static android.service.notification.NotificationListenerService.Ranking.USER_SENTIMENT_NEUTRAL;
 
+import static com.android.internal.widget.LockPatternUtils.StrongAuthTracker.STRONG_AUTH_REQUIRED_AFTER_USER_LOCKDOWN;
 import static com.android.server.notification.NotificationManagerService.ACTION_DISABLE_NAS;
 import static com.android.server.notification.NotificationManagerService.ACTION_ENABLE_NAS;
 import static com.android.server.notification.NotificationManagerService.ACTION_LEARNMORE_NAS;
@@ -225,7 +227,6 @@
 import java.util.Collections;
 import java.util.List;
 import java.util.Map;
-import java.util.Set;
 import java.util.concurrent.CountDownLatch;
 import java.util.function.Consumer;
 
@@ -411,8 +412,26 @@
         interface NotificationAssistantAccessGrantedCallback {
             void onGranted(ComponentName assistant, int userId, boolean granted, boolean userSet);
         }
+
+        class StrongAuthTrackerFake extends NotificationManagerService.StrongAuthTracker {
+            private int mGetStrongAuthForUserReturnValue = 0;
+            StrongAuthTrackerFake(Context context) {
+                super(context);
+            }
+
+            public void setGetStrongAuthForUserReturnValue(int val) {
+                mGetStrongAuthForUserReturnValue = val;
+            }
+
+            @Override
+            public int getStrongAuthForUser(int userId) {
+                return mGetStrongAuthForUserReturnValue;
+            }
+        }
     }
 
+    TestableNotificationManagerService.StrongAuthTrackerFake mStrongAuthTracker;
+
     private class TestableToastCallback extends ITransientNotification.Stub {
         @Override
         public void show(IBinder windowToken) {
@@ -532,6 +551,9 @@
 
         mService.setAudioManager(mAudioManager);
 
+        mStrongAuthTracker = mService.new StrongAuthTrackerFake(mContext);
+        mService.setStrongAuthTracker(mStrongAuthTracker);
+
         mShortcutHelper = mService.getShortcutHelper();
         mShortcutHelper.setLauncherApps(mLauncherApps);
         mShortcutHelper.setShortcutServiceInternal(mShortcutServiceInternal);
@@ -8263,4 +8285,44 @@
             }
         }
     }
+
+    @Test
+    public void testStrongAuthTracker_isInLockDownMode() {
+        mStrongAuthTracker.setGetStrongAuthForUserReturnValue(
+                STRONG_AUTH_REQUIRED_AFTER_USER_LOCKDOWN);
+        mStrongAuthTracker.onStrongAuthRequiredChanged(mContext.getUserId());
+        assertTrue(mStrongAuthTracker.isInLockDownMode());
+        mStrongAuthTracker.setGetStrongAuthForUserReturnValue(0);
+        mStrongAuthTracker.onStrongAuthRequiredChanged(mContext.getUserId());
+        assertFalse(mStrongAuthTracker.isInLockDownMode());
+    }
+
+    @Test
+    public void testCancelAndPostNotificationsWhenEnterAndExitLockDownMode() {
+        // post 2 notifications from 2 packages
+        NotificationRecord pkgA = new NotificationRecord(mContext,
+                generateSbn("a", 1000, 9, 0), mTestNotificationChannel);
+        mService.addNotification(pkgA);
+        NotificationRecord pkgB = new NotificationRecord(mContext,
+                generateSbn("b", 1001, 9, 0), mTestNotificationChannel);
+        mService.addNotification(pkgB);
+
+        // when entering the lockdown mode, cancel the 2 notifications.
+        mStrongAuthTracker.setGetStrongAuthForUserReturnValue(
+                STRONG_AUTH_REQUIRED_AFTER_USER_LOCKDOWN);
+        mStrongAuthTracker.onStrongAuthRequiredChanged(mContext.getUserId());
+        assertTrue(mStrongAuthTracker.isInLockDownMode());
+
+        // the notifyRemovedLocked function is called twice due to REASON_LOCKDOWN.
+        ArgumentCaptor<Integer> captor = ArgumentCaptor.forClass(Integer.class);
+        verify(mListeners, times(2)).notifyRemovedLocked(any(), captor.capture(), any());
+        assertEquals(REASON_CANCEL_ALL, captor.getValue().intValue());
+
+        // exit lockdown mode.
+        mStrongAuthTracker.setGetStrongAuthForUserReturnValue(0);
+        mStrongAuthTracker.onStrongAuthRequiredChanged(mContext.getUserId());
+
+        // the notifyPostedLocked function is called twice.
+        verify(mListeners, times(2)).notifyPostedLocked(any(), any());
+    }
 }