Triplesec

Triple-press a mouse side button to lock your Mac.

For one situation: a MacBook with the lid closed and an external display attached keeps the screen awake and unlocked. Triplesec is invisible — no window, Dock icon, or menu bar item — runs at login, and writes nothing to disk.

Gesture

• 3 presses of any one side button, ≤ 0.5s apart
• Back/forward keep working; left, right, and middle clicks are ignored

Requirements

• macOS 26.5+
• A mouse with side buttons
• Xcode and a Developer ID Application certificate

Caveats

• Locks via a private macOS function: not App Store-compatible, and may break on a future macOS update.
• Needs Input Monitoring permission.

Install

No prebuilt release; build from source. Replace <YOUR NAME> and <TEAM ID>.

xcodebuild -project Triplesec.xcodeproj -scheme Triplesec -configuration Release \
  -derivedDataPath build \
  CODE_SIGN_STYLE=Manual \
  CODE_SIGN_IDENTITY="Developer ID Application: <YOUR NAME> (<TEAM ID>)" \
  DEVELOPMENT_TEAM=<TEAM ID>

Sign without Xcode's development entitlement:

codesign --force --options runtime --timestamp \
  -s "Developer ID Application: <YOUR NAME> (<TEAM ID>)" \
  build/Build/Products/Release/Triplesec.app

Install and launch:

ditto build/Build/Products/Release/Triplesec.app /Applications/Triplesec.app
open /Applications/Triplesec.app

Then:

1. Grant Input Monitoring when prompted, and reopen the app.
2. If prompted, enable the login item in System Settings → General → Login Items.

Keep the app in /Applications — the permission and login-item registration bind to that copy. A different signing certificate counts as a new app and re-prompts for Input Monitoring.

Configure

Triplesec has no settings screen. Edit LockGesture in Triplesec/TriplesecApp.swift, then rebuild and reinstall.

Constant	Default	Controls
minimumButtonNumber	3 (any side button)	Which side button
requiredPresses	3	Press count
maximumInterval	0.5	Max seconds between presses

Button numbers: 0 left, 1 right, 2 middle, 3+ side.

Uninstall

1. System Settings → General → Login Items → turn off Triplesec.
2. Quit Triplesec in Activity Monitor.
3. Delete /Applications/Triplesec.app.

Security

Triplesec is a convenience and must be coupled with good security posture.

Ensure that System Settings → Lock Screen → Require password after screen saver begins or display is turned off is set to Immediately.

How it works

Installs a listen-only CGEvent tap on side-button mouse-down, so clicks reach their normal target. On the gesture, calls SACLockScreenImmediate from the private login.framework. Registers the login item via SMAppService.

Signed but not notarized, so other Macs show a Gatekeeper warning. To remove it, notarize and staple: xcrun notarytool submit, then xcrun stapler staple.