diff --git a/app/src/main/AndroidManifest.xml b/app/src/main/AndroidManifest.xml
index 91dfc6ec..3820008d 100644
--- a/app/src/main/AndroidManifest.xml
+++ b/app/src/main/AndroidManifest.xml
@@ -21,7 +21,7 @@
 
     <uses-permission android:name="android.permission.READ_CONTACTS" />
     <uses-permission
-        android:name="android.permission.USE_FINGERPRINT"
+        android:name="android.permission.USE_BIOMETRIC"
         tools:node="remove" />
 
     <queries>
@@ -55,9 +55,9 @@
             android:name=".activities.ThreadActivity"
             android:configChanges="orientation"
             android:exported="false"
+            android:launchMode="singleTop"
             android:parentActivityName=".activities.MainActivity"
-            android:windowSoftInputMode="adjustResize"
-            android:launchMode="singleTop" />
+            android:windowSoftInputMode="adjustResize" />
 
         <activity
             android:name=".activities.NewConversationActivity"
diff --git a/app/src/main/kotlin/com/simplemobiletools/smsmessenger/activities/MainActivity.kt b/app/src/main/kotlin/com/simplemobiletools/smsmessenger/activities/MainActivity.kt
index 5a748a51..35222eb0 100644
--- a/app/src/main/kotlin/com/simplemobiletools/smsmessenger/activities/MainActivity.kt
+++ b/app/src/main/kotlin/com/simplemobiletools/smsmessenger/activities/MainActivity.kt
@@ -62,6 +62,14 @@ class MainActivity : SimpleActivity() {
 
         updateMaterialActivityViews(main_coordinator, conversations_list, useTransparentNavigation = true, useTopSearchMenu = true)
 
+        if (savedInstanceState == null) {
+            handleAppPasswordProtection {
+                if (!it) {
+                    finish()
+                }
+            }
+        }
+
         if (checkAppSideloading()) {
             return
         }
@@ -636,6 +644,7 @@ class MainActivity : SimpleActivity() {
                     showErrorToast(e)
                 }
             }
+
             else -> toast(R.string.invalid_file_format)
         }
     }
diff --git a/app/src/main/kotlin/com/simplemobiletools/smsmessenger/activities/SettingsActivity.kt b/app/src/main/kotlin/com/simplemobiletools/smsmessenger/activities/SettingsActivity.kt
index fc86ece8..f366044f 100644
--- a/app/src/main/kotlin/com/simplemobiletools/smsmessenger/activities/SettingsActivity.kt
+++ b/app/src/main/kotlin/com/simplemobiletools/smsmessenger/activities/SettingsActivity.kt
@@ -5,9 +5,7 @@ import android.content.Intent
 import android.os.Build
 import android.os.Bundle
 import com.simplemobiletools.commons.activities.ManageBlockedNumbersActivity
-import com.simplemobiletools.commons.dialogs.ChangeDateTimeFormatDialog
-import com.simplemobiletools.commons.dialogs.FeatureLockedDialog
-import com.simplemobiletools.commons.dialogs.RadioGroupDialog
+import com.simplemobiletools.commons.dialogs.*
 import com.simplemobiletools.commons.extensions.*
 import com.simplemobiletools.commons.helpers.*
 import com.simplemobiletools.commons.models.RadioItem
@@ -49,6 +47,7 @@ class SettingsActivity : SimpleActivity() {
         setupGroupMessageAsMMS()
         setupLockScreenVisibility()
         setupMMSFileSizeLimit()
+        setupAppPasswordProtection()
         updateTextColors(settings_nested_scrollview)
 
         if (blockedNumbersAtPause != -1 && blockedNumbersAtPause != getBlockedNumbers().hashCode()) {
@@ -244,6 +243,28 @@ class SettingsActivity : SimpleActivity() {
         }
     }
 
+    private fun setupAppPasswordProtection() {
+        settings_app_password_protection.isChecked = config.isAppPasswordProtectionOn
+        settings_app_password_protection_holder.setOnClickListener {
+            val tabToShow = if (config.isAppPasswordProtectionOn) config.appProtectionType else SHOW_ALL_TABS
+            SecurityDialog(this, config.appPasswordHash, tabToShow) { hash, type, success ->
+                if (success) {
+                    val hasPasswordProtection = config.isAppPasswordProtectionOn
+                    settings_app_password_protection.isChecked = !hasPasswordProtection
+                    config.isAppPasswordProtectionOn = !hasPasswordProtection
+                    config.appPasswordHash = if (hasPasswordProtection) "" else hash
+                    config.appProtectionType = type
+
+                    if (config.isAppPasswordProtectionOn) {
+                        val confirmationTextId = if (config.appProtectionType == PROTECTION_FINGERPRINT)
+                            R.string.fingerprint_setup_successfully else R.string.protection_setup_successfully
+                        ConfirmationDialog(this, "", confirmationTextId, R.string.ok, 0) { }
+                    }
+                }
+            }
+        }
+    }
+
     private fun getMMSFileLimitText() = getString(
         when (config.mmsFileSizeLimit) {
             FILE_SIZE_100_KB -> R.string.mms_file_size_limit_100kb
diff --git a/app/src/main/res/layout/activity_settings.xml b/app/src/main/res/layout/activity_settings.xml
index 7083d0c3..99dfaa9b 100644
--- a/app/src/main/res/layout/activity_settings.xml
+++ b/app/src/main/res/layout/activity_settings.xml
@@ -341,6 +341,32 @@
                     tools:text="@string/mms_file_size_limit_none" />
 
             </RelativeLayout>
+
+            <include
+                android:id="@+id/settings_outgoing_messages_divider"
+                layout="@layout/divider" />
+
+            <TextView
+                android:id="@+id/settings_security_label"
+                style="@style/SettingsSectionLabelStyle"
+                android:layout_width="match_parent"
+                android:layout_height="wrap_content"
+                android:text="@string/security" />
+
+            <RelativeLayout
+                android:id="@+id/settings_app_password_protection_holder"
+                style="@style/SettingsHolderCheckboxStyle"
+                android:layout_width="match_parent"
+                android:layout_height="wrap_content">
+
+                <com.simplemobiletools.commons.views.MyAppCompatCheckbox
+                    android:id="@+id/settings_app_password_protection"
+                    style="@style/SettingsCheckboxStyle"
+                    android:layout_width="match_parent"
+                    android:layout_height="wrap_content"
+                    android:text="@string/password_protect_whole_app" />
+
+            </RelativeLayout>
         </LinearLayout>
     </androidx.core.widget.NestedScrollView>
 </androidx.coordinatorlayout.widget.CoordinatorLayout>