diff --git a/app/src/main/kotlin/io/flamenet/messenger/app/MainActivity.kt b/app/src/main/kotlin/io/flamenet/messenger/app/MainActivity.kt
index ef7f9bf..a25b3a7 100644
--- a/app/src/main/kotlin/io/flamenet/messenger/app/MainActivity.kt
+++ b/app/src/main/kotlin/io/flamenet/messenger/app/MainActivity.kt
@@ -63,6 +63,29 @@ class MainActivity : ComponentActivity() {
     override fun onCreate(savedInstanceState: Bundle?) {
         super.onCreate(savedInstanceState)
 
+        // 🔴 **Screenshots off, and out of the recents thumbnail.**
+        //
+        // The second half is the one that matters and the one nobody thinks
+        // about: without FLAG_SECURE, Android captures whatever is on screen
+        // into the recent-apps preview and WRITES IT TO DISK. An open
+        // conversation therefore exists as a plaintext bitmap outside every
+        // protection this app has — the ratchet, the sealed history file, the
+        // ThisDeviceOnly key — none of which cover a screenshot the OS took of
+        // the rendered thread.
+        //
+        // ⚠️ iOS has had the equivalent since the app lock landed: it obscures
+        // the switcher snapshot on `scenePhase`. Android had nothing at all.
+        // Two platforms disagreeing about a security guarantee is how one of
+        // them ends up being the one that leaks.
+        //
+        // ⚠️ It also blocks screen recording and casting, which is the point,
+        // and is not something to make optional: a setting here is a setting
+        // people leave off and then get surprised by.
+        window.setFlags(
+            android.view.WindowManager.LayoutParams.FLAG_SECURE,
+            android.view.WindowManager.LayoutParams.FLAG_SECURE,
+        )
+
         // ⚠️ Runtime permission on API 33+, which is this app's minSdk. Without
         // it the service runs and every alert is dropped silently — no error,
         // no banner, and nothing on screen to say why. Ask once here rather