MetroVault
Air-gapped Bitcoin signer for offline cold storage. QR-only, no network.
新版本 3.9.0
- Import multisig wallets from vendor setup files (ColdCard, Passport, Jade, Sparrow) via QR
- Hardened security: stronger password key derivation, clock-manipulation-resistant login lockouts, stricter biometrics, BIP-340 nonce hardening
- "Save passphrase locally" is now off by default when creating a wallet
- New guide for setting up a dedicated air-gapped signing device
- Slightly smaller APK and improved UI responsiveness
- Hardened security: stronger password key derivation, clock-manipulation-resistant login lockouts, stricter biometrics, BIP-340 nonce hardening
- "Save passphrase locally" is now off by default when creating a wallet
- New guide for setting up a dedicated air-gapped signing device
- Slightly smaller APK and improved UI responsiveness
MetroVault turns an Android phone into a secure, air-gapped Bitcoin signing device like a cold-storage hardware wallet. It acts as an offline signer for your watch-only wallets (such as Sparrow, BlueWallet, or Electrum) running on an online device. Your private keys are generated and kept on a phone that never connects to the internet; all communication happens through QR codes, and network access is blocked at the Android level.
Because the keys never touch an online device, the attack surface for theft and malware is dramatically reduced. MetroVault is fully open source and auditable, built on a custom Kotlin Bitcoin library so every cryptographic operation can be reviewed.
Security
* Air-gapped operation — designed for devices with no internet (airplane mode, Wi-Fi/Bluetooth off)
* Dual-layer encryption — AES-256-GCM with PBKDF2 (210k iterations) plus the Android Keystore
* Biometric unlock — hardware-backed fingerprint/face authentication
* Plausible deniability — separate "Main" and "Decoy" wallets behind different passwords
* Brute-force protection — exponential backoff with lockout, and an optional automatic wipe after repeated failed logins
* Screenshots and screen recording are blocked app-wide
Wallets
* Single-sig and multi-sig (collaborative custody) support
* Address types: Native SegWit (bc1q), Taproot (bc1p), Nested SegWit (3...) and Legacy (1...)
* BIP-352 Silent Payments support, both to send to or spend from an SP wallet
* BIP-39 passphrase support, saved locally or kept in memory only
* BIP-85 derivation of child seeds and passwords
* Custom entropy from dice rolls or coin flips, plus mnemonic checksum tools
* Testnet4 support for testing
Transaction signing
* PSBT workflow (BIP-174) for single-sig and multi-sig
* Air-gapped flow: scan PSBT, verify, sign, export — entirely by QR
* Animated QR support: BC-UR (v1/v2) and BBQr for large transactions
* On-device address verification and watch-only XPUB/descriptor export
* Message signing and verification
Permissions
MetroVault requests only the camera (optional, for scanning QR codes) and biometric permissions. It has no internet permission and cannot connect to any network.
Because the keys never touch an online device, the attack surface for theft and malware is dramatically reduced. MetroVault is fully open source and auditable, built on a custom Kotlin Bitcoin library so every cryptographic operation can be reviewed.
Security
* Air-gapped operation — designed for devices with no internet (airplane mode, Wi-Fi/Bluetooth off)
* Dual-layer encryption — AES-256-GCM with PBKDF2 (210k iterations) plus the Android Keystore
* Biometric unlock — hardware-backed fingerprint/face authentication
* Plausible deniability — separate "Main" and "Decoy" wallets behind different passwords
* Brute-force protection — exponential backoff with lockout, and an optional automatic wipe after repeated failed logins
* Screenshots and screen recording are blocked app-wide
Wallets
* Single-sig and multi-sig (collaborative custody) support
* Address types: Native SegWit (bc1q), Taproot (bc1p), Nested SegWit (3...) and Legacy (1...)
* BIP-352 Silent Payments support, both to send to or spend from an SP wallet
* BIP-39 passphrase support, saved locally or kept in memory only
* BIP-85 derivation of child seeds and passwords
* Custom entropy from dice rolls or coin flips, plus mnemonic checksum tools
* Testnet4 support for testing
Transaction signing
* PSBT workflow (BIP-174) for single-sig and multi-sig
* Air-gapped flow: scan PSBT, verify, sign, export — entirely by QR
* Animated QR support: BC-UR (v1/v2) and BBQr for large transactions
* On-device address verification and watch-only XPUB/descriptor export
* Message signing and verification
Permissions
MetroVault requests only the camera (optional, for scanning QR codes) and biometric permissions. It has no internet permission and cannot connect to any network.
版本
雖然在下方可選擇下載 APK 檔案，但要留意這樣的安裝方式將不會收到更新通知，是一種較不安全的下載方法。建議您先安裝 F-Droid 用戶端使用。
下載 F-Droid-
arm64-v8aarmeabi-v7ax86x86_64此版本需要 Android 8.0 或更高的版本。
此套件包由原開發者建置和簽署，並保證與此原始碼 Tarball 保持一致。
-
arm64-v8aarmeabi-v7ax86x86_64此版本需要 Android 8.0 或更高的版本。
此套件包由原開發者建置和簽署，並保證與此原始碼 Tarball 保持一致。
-
arm64-v8aarmeabi-v7ax86x86_64此版本需要 Android 8.0 或更高的版本。
此套件包由原開發者建置和簽署，並保證與此原始碼 Tarball 保持一致。
新版本 3.8.7
- Import Multisig Wallet is now available directly from the add-wallet menu on the home screen
- Refreshed the app icon for consistent display across launchers and F-Droid
- Documentation and reproducible-build improvements
- Refreshed the app icon for consistent display across launchers and F-Droid
- Documentation and reproducible-build improvements
新版本 3.8.6
- Added BIP-352 Silent Payments support
- Added multisig wallet registration and verification to guard against tampered descriptors and deceptive change outputs
- Added BIP-322 message signing
- UI cleanups and stability improvements
- Added multisig wallet registration and verification to guard against tampered descriptors and deceptive change outputs
- Added BIP-322 message signing
- UI cleanups and stability improvements