Keyboard Lock: Lock your laptop keyboard while you clean it (Windows)

The problem

Wiping a keyboard while the computer is on means every key you touch types something, so you end up with gibberish in whatever window is open. I wanted one shortcut that switches the keys off while I clean and back on when I am done, in a tool small enough to read in full: a single C# file with no installer, no network access, no settings files and nothing to install beyond the .NET Framework that already ships with Windows 10 and 11.

What it does

• Turns keyboard input on and off with the Ctrl+Alt+K shortcut, a tray menu, or a double-click
• Keeps the mouse and trackpad active so you can always restore typing from the tray icon
• Automatically restores keyboard input after 10 minutes so you cannot get locked out permanently
• Releases modifier keys (Ctrl, Alt, Shift and Windows) on activation to prevent stuck keys
• Displays a warning sign on the tray icon and shows a notification while keys are turned off
• Never records, stores, or transmits keystrokes anywhere

How it works

Keyboard Lock uses a Windows low-level keyboard hook, a built-in operating system mechanism that checks key presses before applications receive them, to decide whether to let a key through or swallow it. When active, it stops keyboard signals from reaching open programs while letting mouse and trackpad events pass through normally.

The entire program is written in a single C# source file of about 140 lines. It runs locally as a system tray program (the icon area near the clock) with no network access, no configuration files, and no dependencies beyond the .NET Framework included with Windows 10 and Windows 11.

Get started

1. Build from source

   & "$env:WINDIR\Microsoft.NET\Framework64\v4.0.30319\csc.exe" /nologo /target:winexe /out:KeyboardLock.exe /reference:System.Windows.Forms.dll /reference:System.Drawing.dll KeyboardLock.cs

   Run this command in PowerShell to compile KeyboardLock.exe using the built-in Windows C# compiler.

2. Start the app

   Launch KeyboardLock.exe to display the keyboard icon in your system tray.

3. Turn off keys to clean

   Press Ctrl+Alt+K to turn off keyboard input and safely wipe your keys.

4. Restore keyboard input

   Press Ctrl+Alt+K again or double-click the tray icon to get your keyboard back.

5. Exit the app

   Right-click the tray icon and choose Exit when you want to quit.

macOS and Linux (beta)

Keyboard Lock now also has macOS and Linux versions with the same Ctrl+Alt+K shortcut (Control+Option+K on a Mac), the same 10-minute auto-unlock and a working mouse. They are in beta: built and checked with automated tests, but not yet tested on real Mac or Linux hardware.

bash setup.sh
bash launch.sh

On a Mac, allow Accessibility and Input Monitoring for the terminal in System Settings, then relaunch. On Linux, your user needs access to keyboard input devices, usually by joining the input group:

sudo usermod -aG input "$USER"

The full steps and known limits are in the README.

Requirements

• Windows 10 or Windows 11
• .NET Framework (ships with Windows 10 and Windows 11)
• PowerShell (to compile the source file)
• macOS (beta): macOS 11 or later and Python 3.9 or later
• Linux (beta): Python 3.9 or later and access to /dev/input devices

Questions