Screen Prank Locker

A macOS prank app that locks the screen with transparent overlays, blocks all keyboard/mouse/trackpad input, and trolls anyone who tries to use your computer. Deactivate by typing a secret sequence, using Touch ID, or with an emergency key combo.

Features

• Full-screen overlay covering all connected displays
• 6 protection modes — silent, flash, flash & sound, fart sounds, custom MP3s, or webcam photo capture
• Webcam prank — photographs the intruder and displays the photo on-screen with a funny caption
• Touch ID unlock — authenticate with biometrics to deactivate
• Multi-display support — dynamically adapts when monitors are connected/disconnected
• Configurable emergency stop hotkey to instantly kill the session
• Failsafe timeout to auto-deactivate after a set duration
• Persistent configuration saved to ~/.prank-locker/config.json

Requirements

• macOS 13.0+
• Swift 5.9+ / Xcode 15+

Quick Start

swift build
.build/debug/ScreenPrankLocker

On first launch the app requests all required permissions (Accessibility, Camera, Touch ID), then shows the configuration window. Adjust your settings and click Activate Prank Lock to start a session.

Build

Debug

swift build

Release App Bundle

make app        # Creates build/ScreenPrankLocker.app

Installer Package / DMG

make pkg        # Creates build/ScreenPrankLocker-1.0.0.pkg
make dmg        # Creates build/ScreenPrankLocker-1.0.0.dmg

Installation

/Applications/ScreenPrankLocker.app/Contents/MacOS/ScreenPrankLocker Because this tool interacts with system security and the camera, macOS Gatekeeper will initially block it since it is an unsigned binary. You will need to strip the quarantine attribute after downloading it.

1. Go to the Releases page and download the latest ScreenPrankLocker-x.x.x.dmg file.

2. Open the .dmg and drag the app into your /Applications folder.

3. Open your Terminal and run the following command to remove the Apple quarantine flag:

/usr/bin/xattr -cr /Applications/ScreenPrankLocker.app

You can now launch the app normally from your Applications folder or Spotlight.

Other Make Targets

Target	Description
build	Compile release binary
app	Build .app bundle
pkg	Build macOS installer package
dmg	Build disk image with drag-install
install	Copy .app to /Applications
test	Run test suite
run	Build & run in one step
clean	Remove build artifacts

How It Works

1. Launch — the app requests permissions, then shows a configuration window
2. Configure — set your deactivation sequence, protection mode, timeout, etc.
3. Activate — click the Start button (or use the global hotkey / CLI flag)
4. Locked — transparent overlays cover all screens, all input is intercepted
5. Deactivate — type the secret sequence blind, use Touch ID, or hit the emergency stop combo

Activation

Method	Default
Config window	Click Activate Prank Lock
Global hotkey	Ctrl + Option + Cmd + L
CLI flag	--activate

Deactivation

Method	Default
Secret sequence	Type unlock while locked
Touch ID	Fingerprint on supported Macs
Emergency stop	Ctrl + Option + Cmd + Q (configurable)
Failsafe timeout	Auto-deactivates after 30 minutes

Protection Modes

Controls how the lock screen reacts when someone tries to interact:

Mode	Behavior
Silent	No visual or audio feedback
Flash	Screen flashes white (default)
Flash & Sound	Flash + configurable system alert sound
Fart Prank	Plays random fart sounds with cooldown
Custom MP3s	Plays random .mp3 files from a configured directory
Webcam Prank	Captures a photo of the intruder with the webcam, displays it on-screen with a funny caption

Configuration

Settings are stored in ~/.prank-locker/config.json (created on first run):

{
    "activationShortcut": { "modifiers": ["control", "option", "command"], "keyCode": 37 },
    "deactivationSequence": "unlock",
    "imageIntervalSeconds": 3.0,
    "maxSimultaneousImages": 15,
    "failsafeTimeoutMinutes": 30,
    "protectionMode": "flash",
    "alertSoundName": "Basso",
    "fartSoundsDirectory": "~/.prank-locker/sounds/farts/",
    "customSoundsDirectory": "~/.prank-locker/sounds/custom/",
    "fartCooldownSeconds": 3.0,
  "emergencyStopShortcut": { "modifiers": ["control", "option", "command"], "keyCode": 12 },
  "telegramBotToken": null,
  "telegramChatID": null
}

Telegram Integration

The Webcam Prank mode can optionally send the captured intruder photo to a Telegram chat. To enable this, add telegramBotToken and telegramChatID to your ~/.prank-locker/config.json.

Steps:

1. Create a bot with @BotFather on Telegram and copy the bot token.
2. Obtain the target chat ID (message the bot and check getUpdates or use a helper bot like @userinfobot).
3. Add the values to your config. Minimal keys:

"telegramBotToken": "123456:ABC-DEF1234ghIkl-zyx57W2v1u123ew11",
"telegramChatID": "987654321"

Example webcam-focused configuration:

{
  "activationShortcut": { "modifiers": ["control", "option", "command"], "keyCode": 37 },
  "deactivationSequence": "unlock",
  "imageIntervalSeconds": 3.0,
  "maxSimultaneousImages": 15,
  "failsafeTimeoutMinutes": 30,
  "protectionMode": "webcamPrank",
  "alertSoundName": "Basso",
  "fartSoundsDirectory": "~/.prank-locker/sounds/farts/",
  "customSoundsDirectory": "~/.prank-locker/sounds/custom/",
  "fartCooldownSeconds": 3.0,
  "emergencyStopShortcut": { "modifiers": ["control", "option", "command"], "keyCode": 12 },
  "telegramBotToken": "123456:ABC-DEF1234ghIkl-zyx57W2v1u123ew11",
  "telegramChatID": "987654321"
}

Keep your bot token private; anyone with it can send messages as your bot.

Custom Prank Images

Drop PNG or JPEG files into ~/.prank-locker/images/. Falls back to built-in defaults if empty.

Custom Fart Sounds

Place .mp3 files in ~/.prank-locker/sounds/farts/ or change the directory in config. The app ships with 8 built-in fart sounds.

Custom MP3 Mode

Set Protection Mode to Custom MP3s, then point the app at any directory containing .mp3 files. A random file from that directory will be played on each interaction attempt.

Alert Sounds (Flash & Sound mode)

Any macOS system sound name works: Basso, Blow, Bottle, Frog, Funk, Glass, Hero, Morse, Ping, Pop, Purr, Sosumi, Submarine, Tink.

Permissions

On first launch the app requests all required permissions upfront:

Permission	Purpose	Required?
Accessibility	Intercept keyboard & mouse events to block input	Yes — core functionality won't work without it
Camera	Capture intruder photos in Webcam Prank mode	Optional — webcam prank gracefully degrades
Touch ID	Biometric unlock	Optional — falls back to keyboard sequence

If Accessibility is not granted, the app will guide you to System Settings → Privacy & Security → Accessibility to enable it.

Resetting Permissions

If you need macOS to prompt again for camera or accessibility access, reset the app's TCC entries:

tccutil reset Camera com.pranklocker.screenpranklocker
tccutil reset Accessibility com.pranklocker.screenpranklocker

After resetting, relaunch the app and macOS should show the permission prompts again.

Running Tests

swift test

The test suite includes unit tests and property-based tests (via SwiftCheck).

License

Private project.