Download ChildLock.exe (about 390 KB, no installer)

ChildLock

Lock your keyboard and mouse with one shortcut, so a kid (or a cat) can bang on the keys and grab the mouse without anything happening. Whatever is on screen keeps playing. Type a secret word to unlock.

Made for:

• letting a kid watch a video without pausing, closing or "fixing" it
• stepping away for a minute without your open work getting wrecked
• wiping the keyboard and mouse without triggering anything

Features

• Locks everything: every key, including Win, Alt+Tab, Alt+F4, Ctrl+Esc, media keys and volume keys, plus the whole mouse or touchpad (movement, clicks and scrolling). The cursor stays frozen.
• Or just half of it: lock only the keyboard (let them click around a game) or only the mouse (so a video can't be paused by a stray click while you type).
• Unlock with a secret word or phrase: just type it while locked (default unlock, but pick your own). Spaces are allowed, so purple giraffe works. Random key mashing won't hit a decent word: in a test of 1,000,000 random key presses unlock never unlocked.
• Or hold the hotkey: hold the lock hotkey (Ctrl+Alt+L) for 3 seconds to unlock, without typing anything.
• Cleaning mode: every screen goes black so smudges and dust show up, and the keyboard and mouse are locked while you wipe them. It ends by itself after a minute, or when you unlock.
• Screen stays as it is: a small "Locked" badge appears in the top-right corner of every monitor and clicks pass straight through it (or hide it completely). The PC is kept awake while locked, so a video doesn't get cut off by sleep or the screensaver.
• Countdown before locking: 3 seconds by default (0 to 10), so you can step back or start the video. Press Esc or the hotkey again to cancel.
• Three ways to lock: a hotkey (default Ctrl+Alt+L), the tray menu, or automatically after a set number of idle minutes (off by default).
• Always a way out: pressing Ctrl+Alt+Del, or Windows locking (Win+L), unlocks ChildLock too.
• Keep older kids out of Settings: optionally ask for the unlock word before Settings, pausing or exiting.
• Small and light: one exe of about 390 KB, no installer, and no measurable CPU when idle.
• Follows your Windows light or dark theme, tray menu included.

Requirements

• Windows 10 or 11 (64-bit)
• .NET 10 Desktop Runtime (Windows offers to install it the first time if it's missing)

Install

1. Download ChildLock.exe from the latest release and put it anywhere you like, for example C:\Tools\ChildLock.
2. Run it and click Yes at the Windows admin prompt. With admin rights ChildLock can also block input aimed at admin windows such as Task Manager; without them, Windows would let keys through to those windows. If you click No, ChildLock still runs (and stops asking); you can turn admin rights back on in Settings.
3. A padlock appears in the notification area. On Windows 11 new icons start hidden behind the ^ arrow; drag it onto the taskbar to keep it visible.
4. Optional: open Settings and tick Start ChildLock when I sign in. With admin rights this creates a Task Scheduler task, so it starts with admin rights at sign-in without asking every time. Without admin rights it uses the normal per-user startup entry instead.

ChildLock shows its notifications as Windows toasts, some with buttons such as Open Settings. For Windows to show them under ChildLock's name, it adds a "ChildLock" shortcut to your Start menu the first time it shows one. ChildLock.exe --uninstall removes it again.

Using it

The badge counts down, then shows what's locked. The dots for each correct character of the unlock word are optional.

To	Do this
Lock	Press Ctrl+Alt+L, or right-click the padlock and choose Lock now
Lock only the keyboard or only the mouse	Right-click the padlock and choose Lock only, or make it the default in Settings
Clean the screen and keyboard	Right-click the padlock and choose Cleaning mode
Cancel the countdown	Press Esc, or press the hotkey again
Unlock	Type the unlock word (default unlock), or hold the lock hotkey for 3 seconds. Nothing shows while you type unless you turn on typing dots, so there's nothing for a kid to react to
Unlock a mouse-only lock	Press the lock hotkey again (the keyboard still works, so typing the word would also type it into your app)
Change settings	Right-click the padlock and choose Settings..., or run ChildLock.exe again
Turn the hotkey off for a while	Right-click the padlock and choose Pause hotkey (for example while gaming). Lock now still works
Quit	Right-click the padlock and choose Exit

Hover over the padlock to see the current hotkey and unlock word, in case you forget it. You can hide the word from the tooltip in Settings.

Tray menu

• Lock now: start the countdown and lock (the keyboard and mouse, unless you picked another default)
• Lock only: lock the keyboard and mouse, just the keyboard, or just the mouse
• Cleaning mode: black out every screen and lock everything while you wipe them
• Settings...
• Pause hotkey: ignore the hotkey and auto-lock until you untick it (resets when ChildLock restarts)
• Exit

While locked, the menu only shows that ChildLock is locked; nothing in it can be clicked.

Settings

Setting	Default	Notes
Locking
Lock hotkey	Ctrl+Alt+L	Click the box and press the keys. Must include Ctrl, Alt or Win. If another app already uses the combination, ChildLock tells you
Lock	Keyboard and mouse	What the hotkey, Lock now and auto-lock lock: keyboard and mouse, keyboard only, or mouse only
Countdown	3 seconds	0 to 10. 0 locks instantly
Auto-lock	0 (off)	Lock after this many minutes with no keyboard or mouse input (up to 240). Goes through the countdown like any other lock
Unlocking
Unlock word	unlock	Up to 64 letters, digits and spaces, not case-sensitive. Number-pad digits count too. Short, common or sequential words (abc, 1234, password) are allowed, but Settings warns you that they are easy to hit or guess
Hold to unlock	3 seconds	Hold the lock hotkey this long to unlock (2 to 10, 0 turns it off). Only the exact hotkey counts, and pressing any other key while holding starts over
Show a dot for each correct character	Off	Small dots on the badge while you type the word, so you can see it's being picked up
Show the unlock word in the tray tooltip	On	Turn off if an older kid could read it
Ask for the unlock word to open Settings, pause or exit	Off	Stops someone who doesn't know the word from turning ChildLock off from the tray
Badge and sound
Show the "Locked" badge	On	The countdown badge always shows, so you can still cancel
Play a sound	Off	A short chime when locking and unlocking
Cleaning mode
Ends after	60 seconds	0 to 600. 0 keeps the screens black until you unlock. The screens fade back in over the last few seconds
Startup
Start ChildLock when I sign in	Off	Adds or removes the sign-in entry. If you move the exe, ChildLock updates it the next time it runs
Run as administrator	On	Ask for admin rights at start, so admin windows are locked too. Declining the prompt turns this off

Settings are saved in %APPDATA%\ChildLock\settings.json. The unlock word is stored there as plain text; it's a kid-proofing word, not a password.

What it can't block

• Ctrl+Alt+Del. Windows reserves this combination and no app can block it. ChildLock treats it as your way out: when the Ctrl+Alt+Del screen appears, ChildLock unlocks. A kid pressing those three exact keys together is unlikely, but possible.
• Win+L and Windows locking. If Windows locks, ChildLock unlocks itself. You still need your Windows password or PIN to get back in.
• The power and sleep buttons. Those are handled by Windows power settings, not by apps. To stop a kid turning the PC off, set the power button to "Do nothing" in Control Panel > Power Options > Choose what the power buttons do.
• Touchpad gestures (3 and 4 finger swipes). Normal touchpad movement, taps and scrolling are blocked. Multi-finger gestures are handled inside Windows and have not been verified yet.
• Exclusive full-screen games. Input is still blocked, but the badge may not show on top.
• Touchscreens and pens. Not tested yet, and probably not fully blocked: apps that read touch input directly may still get taps.
• Ending ChildLock from Task Manager. Someone at an unlocked PC can always end it there. The word prompt only protects the tray menu.
• Without admin rights, input aimed at admin windows (Task Manager, an installer, an admin command prompt) still gets through.

If ChildLock ever crashes, Windows removes its input hooks, so the keyboard and mouse always come back.

Command-line options

None are needed for normal use.

Option	What it does
--settings <path>	Use a different settings file. Each settings file gets its own instance
--diag	Write a diagnostics log (diag.log, next to the settings file) with lock events and input-hook timing
--theme light|dark|system	Force the settings window and tray menu theme instead of following Windows
--no-elevate	Don't ask for admin rights this time
--uninstall	Remove the sign-in entry, the Start menu shortcut and toast registration, and optionally your settings. Exit ChildLock first

Uninstall

1. Exit ChildLock (right-click the padlock, Exit).
2. Run ChildLock.exe --uninstall. It removes the sign-in entry, the Start menu shortcut ChildLock made for its notifications and its cached icon, and asks whether to delete your settings too. (If the sign-in task was created with admin rights, removing it needs them as well; ChildLock tells you.)
3. Delete ChildLock.exe.

Building from source

Needs the .NET 10 SDK. The tray icon comes from PureTech.Tray, included as a git submodule, so clone recursively:

git clone --recursive https://github.com/puretechteam/childlock
cd childlock
dotnet build ChildLock.slnx
dotnet test ChildLock.slnx
dotnet publish src/ChildLock -c Release -o publish

In an existing clone, run git submodule update --init first.

Debug builds run as the normal user, so development needs no admin prompt. Release builds ask for admin rights at start. Override either way with -p:ChildLockElevate=true or false.

Every push is built and unit-tested on Windows by GitHub Actions. Pushing a tag such as v0.2.0 (matching <Version> in Directory.Build.props) publishes ChildLock.exe as a GitHub release with the matching CHANGELOG section as its notes.

The test suite includes integration tests that start the real ChildLock.exe and lock this PC's keyboard and mouse for a few seconds at a time, using synthesized input. They prove that nothing leaks through while locked. Skip them with:

dotnet test ChildLock.slnx --filter Category!=Integration

License

MIT, see LICENSE. Made by Pure Tech.