Privacy & Security

ProximityLock takes your privacy as seriously as your security.  This page explains our commitment to keeping your data private and your computer secure.

Privacy Statement

ProximityLock's privacy and security approach is simple:

Your security is ProximityLock's job.  Your privacy is our promise.


Our Privacy Commitment

We designed ProximityLock from the ground up with privacy in mind.  Security software should protect you, not spy on you.

Zero Data Transmission

ProximityLock never transmits anything. Not a single byte of data ever leaves your computer.

There is no data collection, no analytics, no telemetry, no "phone home," no cloud services.  Nothing.  This isn't just a privacy policy promise.  It's technically impossible for ProximityLock to transmit data because it doesn't use network APIs at all.

Passive Monitoring Only

ProximityLock is completely passive.  It simply listens to Bluetooth advertisements that your devices are already broadcasting to the world.  ProximityLock doesn't connect to your devices, doesn't communicate with them, doesn't pair with them.  It just listens.

Think of it like a radio receiver.  It only receives signals, it never transmits.  ProximityLock:

The data ProximityLock observes (signal strength readings) is used for exactly one purpose: determining when to lock your computer.  That's it.

No Data Collection

ProximityLock does not collect, store remotely, or transmit any data about you, your devices, or your usage patterns.  Ever.

Specifically, ProximityLock never collects or transmits:

Local Processing Only

All signal analysis and decision-making happens locally on your computer.  ProximityLock never communicates with external servers or cloud services because it has no network capabilities.

No Network Access

ProximityLock doesn't use internet connections or network services.  It doesn't even request network access permissions from macOS.  Your proximity monitoring works completely offline, and there's no way for ProximityLock to phone home even if it wanted to.

Minimal Permissions

ProximityLock only requests the permissions it absolutely needs to function:

That's it.  No access to your files, contacts, calendar, location, camera, microphone, or anything else.

Security Features

App Sandbox

ProximityLock runs in the macOS App Sandbox, which restricts what the application can access and do.  This provides multiple security benefits:

The sandbox ensures that even if there were a bug or vulnerability in ProximityLock, the damage would be contained.

No Private APIs

ProximityLock uses only public, documented macOS APIs.  This means:

Code Signing

ProximityLock is digitally signed, which provides:

What ProximityLock Does Access

For complete transparency, here's what ProximityLock does access and why:

Bluetooth Device Information

What: Bluetooth device names, identifiers, and signal strength (RSSI)

Why: To detect your selected device and monitor its proximity

Storage: Device selection is stored in user preferences; signal history exists only in memory while app runs

System Event Control

Why: To activate the screen saver (which locks your screen)

Usage: Only used when your device goes out of range or you use Test Lock

User Preferences

What: Your device selection, threshold, timeout, and monitoring state

Why: To remember your settings between app launches

Storage: Stored in standard macOS user preferences (~/Library/Preferences)

Data Retention

ProximityLock retains minimal data, and only what's necessary for operation:

Persisted Settings

Stored in user preferences:

Temporary Data (Memory Only)

Stored in memory while app runs, cleared when app quits:

No Logging

ProximityLock uses standard macOS logging (OSLog) for debugging purposes, but:

Your Security Responsibility

While ProximityLock provides automatic locking, remember that it's one layer of security.  For complete protection:

Enable Screen Lock Password: ProximityLock activates your screen saver, but you must configure macOS to require a password:

System Settings → Lock Screen → "Require password immediately after sleep or screen saver begins"

Without this, your screen saver can be dismissed without authentication.

Best Practices

Third-Party Access

ProximityLock does not integrate with any third-party services, analytics platforms, or advertising networks.  There are no third parties that have access to any data because there is no data to access.

Uninstalling ProximityLock

If you decide to uninstall ProximityLock, you can completely remove all traces:

  1. Quit ProximityLock
  2. Drag ProximityLock.app to the Trash
  3. Remove from Login Items (System Settings → General → Login Items & Extensions)
  4. Optionally delete preferences: ~/Library/Preferences/com.sinz.ProximityLock.plist

After uninstalling, no ProximityLock data remains on your system.

Updates and Changes

If ProximityLock's privacy practices ever change, we'll update both the application and this help documentation.  However, our commitment to privacy is fundamental to ProximityLock's design and purpose.  We will never add tracking, analytics, or data collection.

Questions or Concerns

If you have questions about privacy or security, or if you'd like to verify any of the claims made on this page, ProximityLock's behavior can be verified through:


Design Trade-offs: Privacy First

ProximityLock could do more, but we chose not to, and here's why.

What We Could Have Built

With historical data storage, ProximityLock could be smarter.  We could analyze days or weeks of your device's signal patterns, use statistical models to predict when you're actually leaving versus just shifting in your chair, and automatically adjust thresholds based on your environment.  The data requirements are minimal.  Days of signal history would take up less storage than a single photo.

This would mean fewer false alarms, better accuracy, and less manual tuning.  It's technically feasible and would genuinely improve the user experience.

Why We Didn't

Privacy.  Pure and simple.

One of the core constraints we set for ProximityLock is this: the application stores nothing beyond a few configuration settings.  No historical signal behaviors, no long-term tracking, no pattern analysis data.  When you see that ProximityLock requests Bluetooth access, we want you to know with absolute certainty that we're not collecting or analyzing your data over time.

We wanted to be able to say (and mean it) that ProximityLock stores no information and processes nothing except what's needed in the moment to decide whether to lock your screen.  That's it.

What We Did Instead

ProximityLock keeps signal history only in memory while the app runs (up to 200 readings or 10 minutes).  When you quit the app, that data disappears.  We use some dynamic signal management (simple math to scale the timeout based on how far the current signal is from your threshold), but it's deliberately basic.  Just enough to catch lock events a bit earlier while avoiding false alarms from random interference in the noisy Bluetooth environment.

It's not as sophisticated as it could be, but it's honest.  And that honesty matters when you're trusting an app with your security.

The Trade-off

Yes, you might need to adjust your threshold and timeout settings to match your environment.  Yes, you might experience an occasional false alarm or need to tune things after moving to a new workspace.  That's the price of privacy-first design.

We think it's worth it.  When security software asks for system access, you should be able to trust it completely.  ProximityLock's simplicity is intentional.  It's easier to trust software that does less, stores nothing, and can prove it.

© 2025-2026 - Michael Sinz