Privacy Policy

OpenEMF is designed with privacy as a core principle. Your data stays on your device.

Last updated: December 31, 2024

TL;DR - The Short Version

  • No data collection: We don't collect, store, or transmit your personal data
  • All local: All measurements are stored only on your device
  • No accounts: No registration, login, or cloud sync required
  • No analytics: No Firebase, Google Analytics, or tracking SDKs
  • Open source: Verify everything yourself in the source code

What Data Does OpenEMF Collect?

None. OpenEMF does not collect, transmit, or store any data on external servers.

When you take a measurement, the following data is stored locally on your device only:

  • E-Score and exposure level
  • WiFi network names and signal strengths (not passwords)
  • Bluetooth device names and signal strengths
  • Cellular tower information
  • Magnetic field readings
  • GPS coordinates (if you grant location permission)
  • Timestamp of measurement

Why Does OpenEMF Need Permissions?

Location Permission

Required by Android to scan WiFi networks and cellular towers. This is an Android security requirement, not our choice. Your location data is stored locally only and never transmitted.

Bluetooth Permission

Used to detect nearby Bluetooth devices and measure their signal strength. No pairing or data exchange occurs.

Phone State Permission

Used to read cellular tower information. We do not access call logs, contacts, or any personal information.

Internet Permission

Used only to load map tiles from OpenStreetMap. No personal data is transmitted.

No Tracking, No Analytics

OpenEMF contains:

  • ✗ No Google Analytics
  • ✗ No Firebase
  • ✗ No crash reporting services
  • ✗ No advertising SDKs
  • ✗ No third-party trackers
  • ✗ No telemetry

Verify It Yourself

OpenEMF is 100% open source under the BSD 3-Clause license. You can:

  • Read every line of code
  • Build the app yourself from source
  • Audit network traffic with tools like Wireshark
  • Decompile the APK to verify it matches the source
View Source Code

How to Verify the APK is Safe

1. Check APK Signature

Verify the APK is signed with our official key:

apksigner verify --print-certs app-release.apk

2. Scan with VirusTotal

Upload the APK to VirusTotal for a multi-engine virus scan:

www.virustotal.com

3. Monitor Network Traffic

Use tools like NetGuard, PCAPdroid, or Wireshark to verify the app only connects to OpenStreetMap tile servers.

4. Build From Source

Clone the repository and build the APK yourself. This guarantees you're running exactly what's in the source code.

Deleting Your Data

Since all data is stored locally on your device:

  • Clear app data: Settings → Apps → OpenEMF → Clear Data
  • Uninstall: Removes all data completely
  • In-app: Settings → Clear History

There's nothing to delete from our servers because we don't have your data.

Contact

If you have questions about this privacy policy or OpenEMF's data practices:

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