Bitcoin Silver Android Wallet

Mobile wallet for BitcoinSilver (BTCS)
Built with Flutter for Android & iOS

Website • Explorer

Features

• BIP39 Seed Phrase Support: Create or restore wallets using 12 or 24-word recovery phrases.
• Cross-Platform Compatibility: Uses standard derivation path m/44'/0'/0'/0/0 (same as Web Wallet 2.2).
• Advanced Recovery: Support for raw private key (WIF) recovery and generation.
• Local Transaction Signing (No Node Key Exposure): Transactions are built and signed in-app using local keys, then broadcast as raw hex.
• Seed + WIF Wallet Modes: Users can create/use both mnemonic-based and WIF-based wallets.
• Advanced Send / Coin Control: Select specific confirmed UTXOs, paginate inputs, estimate fees, and preview net send amount.
• Send and Receive: Seamless BTCS transfers for both legacy and SegWit destination types.
• BTCS Address Compatibility: Supports BTCS Bech32 (bs1...) and legacy Base58 address handling in signer and send flow.
• Address Validation Improvements: Debounced validation, scanner/address-book parity, and resilient fallback validation for BTCS RPC edge cases.
• QR Code Scanning: Supports BIP21 URI format for easy transfers.
• Transaction Tracking: Real-time history with smart confirmation tracking and pending-state management.
• Smart Pending Handling: Tracks local pending spends, avoids double-spend UTXO reuse, and keeps balances accurate during mempool transitions.
• Biometric Security: Protect your wallet and recovery phrase with fingerprint or face recognition.
• Secure Storage: Sensitive keys and mnemonics are stored in encrypted secure storage.

Recent Updates

• Upgraded to Flutter 3.44.4 • channel stable
• Upgraded to Android Gradle Plugin (AGP) 9.6.0
• Upgraded to Kotlin 2.4.0
• Migration Flow Hardening:
  • Added explicit migration warning + acknowledgment step before migration starts.
  • Added funded-wallet pre-check for smart fee availability and blocks migration when node fee estimation is unavailable.
  • Added pending-transaction guard: migration is delayed while unconfirmed/pending transactions exist.
  • Added secure-storage preflight and fail-closed behavior before irreversible sweep operations.
  • Added migration integrity checks for migrated private key/address consistency before success handoff.
  • Added detailed failure dialog path so users get clear migration error reasons.
  • Added stage-based migration progress dialogs for both pre-send preparation and send/finalize phases.
  • Added migration interruption handling with explicit user guidance when app context changes mid-flow.
  • Added migration cancellation feedback dialog so exits are not silent.
  • Added one-tap "Copy All Backup Data" action (formatted address + seed + WIF + optional sweep amount).
  • Enforced post-success backup confirmation dialog before final completion.
  • Updated empty-wallet migration success wording to avoid claiming a transaction was sent.
• Fee Estimation Hardening:
  • Handles estimatesmartfee failures explicitly (RPC errors, missing feerate, and feerate: -1 / no estimate).
  • Adds send-time manual fee entry fallback when estimation is unavailable.
  • Shows fee estimation status on Send screen with loading state and warning indicator.
  • Blocks signing/broadcast until a valid fee rate is provided (estimated or manual).
  • Fee-bump retry dialog only runs for transactions that started from estimator-provided fee rates.
• Manual Fee UX Improvements:
  • Unit toggle for sat/vB and BTCS/kvB with conversion.
  • Network-condition presets tuned to current conditions:
    • Low: 0.085 BTCS/kvB
    • High: 0.10 BTCS/kvB
• Resume/Background Reliability:
  • Improved silent transaction refresh behavior so latest transactions are reloaded after app resume/background transitions.
  • Added shared wallet sync coalescing for timer/resume/manual refresh to avoid overlapping sync races.
  • Reduced startup blocking when RPC is unavailable while preserving RPC warning visibility.
• Send Preview Consistency:
  • Transaction preview now updates live on amount edits.
  • Auto input-selection mode now shows computed expected change instead of "Auto".
• Performance improvements and dependency updates.

Quick Start

# Install dependencies
flutter pub get

# Run in development (uses public RPC)
flutter run

# Build APK
flutter build apk

# Build with custom RPC
flutter build apk --release --obfuscate --split-debug-info=build/app/outputs/symbols --dart-define-from-file=dart_defines.json

Configuration

The wallet connects to the public RPC proxy at https://bitcoinsilver.eu/btcs-rpc by default (no authentication required).

For custom RPC node, create dart_defines.json:

{
  "RPC_URL": "http://your-rpc:port",
  "RPC_USER": "your_user",
  "RPC_PASSWORD": "your_password"
}

Build for Production

# Android APK
flutter build apk --release --dart-define-from-file=dart_defines.json

# Android App Bundle (Play Store)
flutter build appbundle --release --obfuscate \
  --split-debug-info=build/app/outputs/symbols \
  --dart-define-from-file=dart_defines.json

# iOS
flutter build ios --release --dart-define-from-file=dart_defines.json

Output locations:

• APK: build/app/outputs/flutter-apk/app-release.apk
• AAB: build/app/outputs/bundle/release/app-release.aab

Security

• Private keys stored in encrypted secure storage (Keychain/KeyStore)
• Optional biometric authentication
• RPC credentials injected at build time, never hardcoded
• No personal data collected

Never commit dart_defines.json or .env to version control.

Migration Safety Checklist

Use this quick checklist after migration-related changes:

• Warning + Consent: Migration starts only after user acknowledgment dialog is accepted.
• Pending Guard: Migration is blocked while pending/unconfirmed transactions exist.
• Fee Guard: Funded migration is blocked when smart fee estimation is unavailable.
• Storage Guard: Secure storage preflight succeeds before sweep/save steps.
• Integrity Guard: On success, migrated private key and derived address are validated.
• Backup Gate: Success requires user backup confirmation dialog completion.
• Backup Copy Action: Users can copy all migration backup data in one formatted payload.
• Interruption UX: Context-loss/interruption is surfaced with a retry-in-one-go notice.
• Failure UX: Any failure path shows a clear reason dialog and keeps old wallet active.
• Resume Sync: After app resume/background transitions, latest transactions reload correctly.

Suggested manual smoke test sequence:

1. Empty wallet migration (12-word and 24-word).
2. Funded wallet migration with small amount.
3. Funded wallet migration with larger/fragmented UTXOs.
4. Pending transaction scenario (verify migration is delayed).
5. Smart fee unavailable scenario (verify migration is blocked with explanation).

Contributing

Contributions are welcome! Please:

1. Fork the repository
2. Create a feature branch (git checkout -b feature/my-feature)
3. Commit your changes (git commit -m 'Add my feature')
4. Push to the branch (git push origin feature/my-feature)
5. Open a Pull Request

For bugs or feature requests, please open an issue.

- Current Google Play version 5.6

License

MIT