Repairing an Android NFC App (APK file) - NFC tags not working!

Job ID: 39301664

Budget: $30 – $250 USD

ONLY FOR NFC & AES / ENCRYPTION EXPERT! DON'T RESPOND IF YOU HAVE NO NFC TOOLS AND NTAG 215 AND NTAG 424 DNA + NFC READERS FOR TESTING THE TO BE REPAIRED APK APP!

Fix NFC Functionality in Android NFC mobile App in APK file format
Project Description:
I need an experienced Android developer to debug, repair, and fully implement the NFC read/write functionality in an existing app (APK file). The app uses 2 separate NFC tags to store encrypted passwords, but the current implementation fails to reliably detect tags or write data.

Key Requirements:
Debug & Fix NFC Issues:

Diagnose why NFC tag detection/writing fails on some devices (e.g., Samsung, Pixel, POCO).

Ensure compatibility with NTAG215 tags and NTAG 424 DNA (ISO 14443-3/4 standards).

Resolve PendingIntent or ForegroundDispatch issues (if any).

Implement Reliable NFC Workflow:

Write Phase:

Encrypt user passwords (AES-256-GCM) and write to Tag 1 (Black).

Lock the tag with a PIN-derived password to prevent unauthorized access.

Read Phase:

Detect Tag 2 (Silver) to launch the app and prompt for a PIN.

Read encrypted data from Tag 1 (Black) and decrypt it.

Security Enhancements:

Add tag authentication (e.g., SHA-256 hash of PIN + salt) to prevent cloning.

Handle edge cases (e.g., tag removal during write, low NFC signal).

Testing:

Verify functionality on Android 10+ (Samsung, Google, Xiaomi devices).

Ensure the app works offline (no cloud dependency).

Technical Stack:
Language: Kotlin (primary) / Java

Libraries:

android.nfc (core NFC API)

androidx.security.crypto (EncryptedSharedPreferences)

javax.crypto (AES-256-GCM encryption)

Tags: NTAG215 (must support password protection) and NTAG 424 DNA.

Deliverables:
APK mobile app with Fixed NFC 100% reliable read/write operations.

Updated documentation for NFC setup and error handling.

Test reports on NFC equipped Android devices.

Preferred Qualifications:
Prior experience with NFC-enabled apps (e.g., loyalty cards, access control).

Knowledge of Android Keystore and hardware-backed encryption.

Portfolio of apps with NFC functionality (share links).

Budget & Timeline:
Budget:

USD 50.-

Timeline: 4 days (including testing).