windows: protect against screenshots and screen recordings

electrum/gui/qt/__init__.py

@@ -78,7 +78,8 @@ from electrum import constants
 from electrum.gui.common_qt.i18n import ElectrumTranslator
 from electrum.gui.messages import TERMS_OF_USE_LATEST_VERSION
 
-from .util import read_QIcon, ColorScheme, custom_message_box, MessageBoxMixin, WWLabel
+from .util import (read_QIcon, ColorScheme, custom_message_box, MessageBoxMixin, WWLabel,
+                   set_windows_os_screenshot_protection_drm_flag)
 from .main_window import ElectrumWindow
 from .network_dialog import NetworkDialog
 from .stylesheet_patcher import patch_qt_stylesheet
@@ -105,6 +106,20 @@ class OpenFileEventFilter(QObject):
         return False
 
 
+class ScreenshotProtectionEventFilter(QObject):
+    def __init__(self):
+        super().__init__()
+
+    def eventFilter(self, obj, event):
+        if (
+            event.type() == QtCore.QEvent.Type.Show
+            and isinstance(obj, QWidget)
+            and obj.isWindow()
+        ):
+            set_windows_os_screenshot_protection_drm_flag(obj)
+        return False
+
+
 class QElectrumApplication(QApplication):
     new_window_signal = pyqtSignal(str, object)
     quit_signal = pyqtSignal()
@@ -136,9 +151,12 @@ class ElectrumGui(BaseElectrumGui, Logger):
         QGuiApplication.setApplicationName("Electrum")
         self.gui_thread = threading.current_thread()
         self.windows = []  # type: List[ElectrumWindow]
-        self.efilter = OpenFileEventFilter(self.windows)
+        self.open_file_efilter = OpenFileEventFilter(self.windows)
         self.app = QElectrumApplication(sys.argv)
-        self.app.installEventFilter(self.efilter)
+        self.app.installEventFilter(self.open_file_efilter)
+        self.screenshot_protection_efilter = ScreenshotProtectionEventFilter()
+        if sys.platform in ['win32', 'windows'] and self.config.GUI_QT_SCREENSHOT_PROTECTION:
+            self.app.installEventFilter(self.screenshot_protection_efilter)
         self.app.setWindowIcon(read_QIcon("electrum.png"))
         self.translator = ElectrumTranslator()
         self.app.installTranslator(self.translator)
@@ -247,8 +265,11 @@ class ElectrumGui(BaseElectrumGui, Logger):
             return
         self._cleaned_up = True
         self.app.new_window_signal.disconnect()
-        self.app.removeEventFilter(self.efilter)
-        self.efilter = None
+        self.app.removeEventFilter(self.open_file_efilter)
+        self.open_file_efilter = None
+        # it is save to remove the filter, even if it has not been installed
+        self.app.removeEventFilter(self.screenshot_protection_efilter)
+        self.screenshot_protection_efilter = None
         # If there are still some open windows, try to clean them up.
         for window in list(self.windows):
             window.close()

electrum/gui/qt/settings_dialog.py

@@ -24,6 +24,7 @@
 # SOFTWARE.
 
 import ast
+import sys
 from typing import TYPE_CHECKING, Dict
 
 from PyQt6.QtCore import Qt
@@ -262,6 +263,20 @@ class SettingsDialog(QDialog, QtEventListener):
             self.need_restart = True
         filelogging_cb.stateChanged.connect(on_set_filelogging)
 
+        screenshot_protection_cb = checkbox_from_configvar(
+            self.config.cv.GUI_QT_SCREENSHOT_PROTECTION
+        )
+        screenshot_protection_cb.setChecked(self.config.GUI_QT_SCREENSHOT_PROTECTION)
+        if sys.platform not in ['windows', 'win32']:
+            screenshot_protection_cb.setChecked(False)
+            screenshot_protection_cb.setDisabled(True)
+            screenshot_protection_cb.setToolTip(_("This option is only available on Windows"))
+
+        def on_set_screenshot_protection(_x):
+            self.config.GUI_QT_SCREENSHOT_PROTECTION = screenshot_protection_cb.isChecked()
+            self.need_restart = True
+        screenshot_protection_cb.stateChanged.connect(on_set_screenshot_protection)
+
         block_explorers = sorted(util.block_explorer_info().keys())
         BLOCK_EX_CUSTOM_ITEM = _("Custom URL")
         if BLOCK_EX_CUSTOM_ITEM in block_explorers:  # malicious translation?
@@ -386,6 +401,7 @@ class SettingsDialog(QDialog, QtEventListener):
         misc_widgets = []
         misc_widgets.append((updatecheck_cb, None))
         misc_widgets.append((filelogging_cb, None))
+        misc_widgets.append((screenshot_protection_cb, None))
         misc_widgets.append((alias_label, self.alias_e))
         misc_widgets.append((qr_label, qr_combo))
 

electrum/gui/qt/util.py

@@ -6,6 +6,7 @@ import platform
 import queue
 import os
 import webbrowser
+import ctypes
 from functools import partial, lru_cache, wraps
 from typing import (NamedTuple, Callable, Optional, TYPE_CHECKING, List, Any, Sequence, Tuple, Union)
 
@@ -1531,6 +1532,21 @@ def insert_spaces(text: str, every_chars: int) -> str:
     return ' '.join(text[i:i+every_chars] for i in range(0, len(text), every_chars))
 
 
+def set_windows_os_screenshot_protection_drm_flag(window: QWidget) -> None:
+    """
+    sets the windows WDA_MONITOR flag on the window so windows prevents capturing
+    screenshots and microsoft recall will not be able to record the window
+    https://learn.microsoft.com/en-us/windows/win32/api/winuser/nf-winuser-setwindowdisplayaffinity
+    """
+    if sys.platform not in ('win32', 'windows'):
+        return
+    try:
+        window_id = int(window.winId())
+        WDA_MONITOR = 0x01
+        ctypes.windll.user32.SetWindowDisplayAffinity(window_id, WDA_MONITOR)
+    except Exception:
+        _logger.exception(f"failed to set windows screenshot protection flag")
+
 class _ABCQObjectMeta(type(QObject), ABCMeta): pass
 class _ABCQWidgetMeta(type(QWidget), ABCMeta): pass
 class AbstractQObject(QObject, ABC, metaclass=_ABCQObjectMeta): pass

electrum/simple_config.py

@@ -800,6 +800,14 @@ Warning: setting this to too low will result in lots of payment failures."""),
     GUI_QT_SHOW_TAB_CONTACTS = ConfigVar('show_contacts_tab', default=False, type_=bool)
     GUI_QT_SHOW_TAB_CONSOLE = ConfigVar('show_console_tab', default=False, type_=bool)
     GUI_QT_SHOW_TAB_NOTES = ConfigVar('show_notes_tab', default=False, type_=bool)
+    GUI_QT_SCREENSHOT_PROTECTION = ConfigVar(
+        'screenshot_protection', default=True, type_=bool,
+        short_desc=lambda: _("Prevent screenshots"),
+        # currently this option is Windows only, so the description can be specific to Windows
+        long_desc=lambda: _(
+            'Signals Windows to disallow recordings and screenshots of the application window. '
+            'There is no guarantee Windows will respect this signal.'),
+    )
 
     GUI_QML_PREFERRED_REQUEST_TYPE = ConfigVar('preferred_request_type', default='bolt11', type_=str)
     GUI_QML_USER_KNOWS_PRESS_AND_HOLD = ConfigVar('user_knows_press_and_hold', default=False, type_=bool)