# Trusted Device Criteria > To ensure the security and proper functionality of the Software, the following criteria must be met for a device to qualify as trusted: Device State Requirements The device must not: 1. Have an Unlocked Bootloader: * The bootloader must be locked. * For more information on locking the bootloader, see [here](https://source.android.com/devices/bootloader/locking_unlocking?hl=en). 2. Be Rooted: * The device must not have root access (the user must not have root privileges). 3. Have SELinux Disabled or Permissive: * SELinux must be set to **"enforcing" mode**. Devices with SELinux in "disabled" or "permissive" mode are not secure and will be blocked. * For more information on SELinux in Android, see [here](https://source.android.com/docs/security/features/selinux). * How to check: * Certain devices, such as Samsung smartphones, allow users to check the SELinux mode manually. To verify the SELinux state: 1. Go to **Settings** > **About Phone**. 2. Find the section **Software Information** (or similar). 3. Look for **SE for Android** or a similar entry. The SELinux mode should be listed as either **Enforcing** or **Permissive**. * If it shows **Enforcing**, the device is secure and compliant. * If it shows **Permissive** or **Disabled**, the device needs adjustment or replacement. * If a device is flagged due to SELinux misconfiguration, the following options are available: 1. **Adjust SELinux Mode Manually**:\ Advanced users may attempt to change SELinux mode from "permissive" or "disabled" to "enforcing."\ **Warning**: This process involves significant system modifications and could render the device unusable. It is not recommended for non-experts. 2. **Visit a Service Center**:\ You may seek assistance from a professional service center. Specialists at these centers may be able to reconfigure SELinux settings or provide a resolution. 3. **Change the Device**:\ The most straightforward and reliable solution is to replace the device with one meeting security requirements, where SELinux is properly enforced. 4. Be in Developer Mode: * How to check: * **Method 1:** Open "Settings," go to "About phone" or "About tablet," find the "Build number" section (or "MIUI version" on Xiaomi devices), and tap it. If developer mode is enabled, you'll see a confirmation message. * **Method 2:** Open "Settings," select "For Developers" (or "Advanced > For Developers"), and ensure the "Developer Mode" switch at the top is turned off. 5. Be in Debug Mode: * How to check: * **Method 1:** Open "Settings," select "For Developers" (or "Advanced > For Developers" on some devices). In the "Debug" menu, ensure "USB/Wi-Fi Debugging" is not activated. * **Method 2:** Connect the device to a computer and ensure no "USB/Wi-Fi Debugging enabled" notification appears on the smartphone. 6. Pass Google Play Integrity API Checks: * The device must successfully pass the Google Play Integrity API check with the **MEETS\_STRONG\_INTEGRITY** status. * How to check: * To verify the integrity verdict on your device, follow these steps: 1. Enable Play Store's developer options by tapping your profile icon in the Play Store app, then selecting **Settings**. 2. Open the **About** menu and tap **Play Store version** seven times to unlock developer mode. 3. Open the Play Store app, tap your profile icon, then go to **Settings** > **General** > **Developer options**. 4. In the **Play Integrity settings**, tap **Check integrity** to generate the verdict for the device. * For more detailed instructions, see [here](https://developer.android.com/google/play/integrity/additional-tools#check-device). 7. Contain Apps Violating Google's Software Principles: * Apps installed on the device must comply with [Google's Software Principles](https://www.google.com/about/software-principles.html) and [Unwanted Software Policy](https://www.google.com/about/unwanted-software-policy.html). * How to check Google Play Protect status: see [here.](https://support.google.com/accounts/answer/2812853?hl=en\&ref_topic=7189123) ## **Application Installation Source** * The application must be downloaded and installed **only** from the Google Play Store. * Installation from other sources is strictly prohibited, as it violates the License agreement. ## **Safe Usage of the Software** When using the
Android Software ("Software"), the user must not: 1. **Allow Screen Overlays:** * Apps or system functions (e.g., messengers) that overlay the Software screen must be turned off during transactions. * If a message about restricted usage appears, follow the steps [here](https://docs.tapxphone.com/help/faq/payment-acceptance). 2. **Use Split Screen or Broadcast Modes:** * Do not activate split-screen mode or use broadcast functionality from the mobile device. 3. **Use the Camera in Unintended Ways:** * Background apps with camera access must be closed during a transaction. * Disable system functions that keep the screen active due to constant background camera usage (e.g., Face ID features). 4. **Take Screenshots or Record Videos:** * Screenshotting or screen recording is prohibited while using the application. 5. **Turn Off Previously Granted Permissions:** * Ensure that all required permissions remain active for the application. 6. **Use Remote Control Applications:** * Applications like TeamViewer or AirDroid are not allowed. ## **NFC Requirements** The device must have: 1. A functional embedded NFC module. 2. NFC configured to read cards. * **How to check:** * Open "Settings," go to "Connection and Sharing," and ensure NFC is turned on. * If there is an option to choose between "SIM" and "e-wallet," select "e-wallet." ## **Security Recommendations** * **OS Updates:** Regularly update the device’s OS and components to ensure the latest security improvements. * **Trusted Apps:** Only download apps from trusted vendors in the Play Store, verified by Google Play Protect. * **Malware Detection:** Install and update malware detection tools to protect the device.