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Permissions and Settings

The following permissions are necessary for PhonePOS to function correctly:

  • NFC: We use NFC to communicate with cards and other phones to exchange payment information.
  • INTERNET: Required for the communication with our servers.
  • ACCESS_NETWORK_STATE: We react on the current network state and retry requests when the internet connection is reinstated.
  • BLUETOOTH & BLUETOOTH_ADMIN: For our certification we are required to check all connected devices including bluetooth devices. This permission is used until Android 11.
  • BLUETOOTH_CONNECT: If Android 12 and up is used, this permission is used to check the connected bluetooth devices.
  • RECEIVE_BOOT_COMPLETED: When the phone boots up PhonePOS will automatically start up to make payment processing as fast as possible.
  • FOREGROUND_SERVICE: We use foreground services to communicate to our backend and to start our terminal.
    • FOREGROUND_SERVICE_DATA_SYNC: This service type is used for our monitoring component which reports the current attestation state of the phone.
    • FOREGROUND_SERVICE_SPECIAL_USE: This service type is used for our terminal component which processes the sensitive payment data.
  • WAKELOCK: For the monitoring process we acquire a PARTIAL_WAKE_LOCK.
  • SENSOR_ACCELEROMETER: The accelerometer is used during the startup of our software internally.
  • POST_NOTIFICATIONS: Required to provide the overall status of PhonePOS in form of a notification to the user.
  • CAMERA: Used to prevent other apps from accessing the camera during payments, mitigating serious attack vectors:
    • Front camera: Prevents attackers from estimating finger movements to capture the PIN (Personal Identification Number).
    • Back camera: Prevents attackers from capturing images of the presented card and extracting the PAN (Primary Account Number).
  • HIDE_OVERLAY_WINDOWS: On some of our activities we have to supress overlays to protect the privacy of user data.
  • DYNAMIC_RECEIVER_NOT_EXPORTED_PERMISSION: This permission is set in ContextCompat of the AndroidX Core library.
  • Allow unrestricted Power / Battery Mode: Ensures the app is not cleared from memory by the operating system, enabling quick payments at all times.

Battery and Custom Settings​

PhonePOS requires payment background services to run. Power-related system settings can lead to these services being killed.
To avoid such issues it is advised to exclude PhonePOS from any battery optimization.

Example for Android 14:
app-battery-usage.png

Furthermore, some custom android modifications of device manufacturers may interefere with reliable operation. This includes the autostart settings of Xiaomi's MIUI android derivative.

Enable background autostart for PhonePOS under Apps > Permissions > Background autostart:
background-autostart.png

Unihertz devices have some additional settings under Apply advanced settings > App blocker.
For PhonePOS to work in this case, you must either deactivate the app blocker completely or at least remove all restrictions:
app-blocker.png

Please verify if there are similar settings on your device and set them accordingly.
It is a good idea to recommend these changes to your users to improve their experience with PhonePOS.

Checklist​

You can refer to the following checklist to ensure that a device is set up correctly.

  • Permissions are granted
  • NFC is turned on
  • Device Integrity is at least classified as MEETS_DEVICE_INTEGRITY (see here)
  • Network Connection is provided
  • Battery optimization excludes PhonePOS
  • Autostart is enabled for PhonePOS