Keep: FROST Nostr Signer

Keep: FROST Nostr Signer

FROST threshold signer and Nostr event signer for Android

PrivKey LLC Security

Screenshots

Screenshot of Keep: FROST Nostr Signer Screenshot of Keep: FROST Nostr Signer Screenshot of Keep: FROST Nostr Signer Screenshot of Keep: FROST Nostr Signer Screenshot of Keep: FROST Nostr Signer Screenshot of Keep: FROST Nostr Signer

Description

Keep is a FROST (Flexible Round-Optimized Schnorr Threshold Signatures) threshold signing app and dedicated Nostr event signer for Android. It lets you hold FROST key shares on your phone and sign Nostr events without any single device ever holding the full private key.

Keep implements the NIP-55 Android Signer protocol and NIP-46 remote signing, so any compatible Nostr client can request signatures directly.

Features:
- FROST threshold signing (2-of-3, 3-of-5, etc.)
- NIP-55 Android Signer protocol
- NIP-46 remote signing (bunker service)
- Import and export FROST shares via QR code or text
- Multiple account support
- Per-app signing permissions and policies
- Biometric and PIN authentication
- Hardware-backed key storage (Android Keystore)
- NIP-44 encryption and decryption
- SOCKS proxy support (Tor)
- Encrypted backup and restore

What’s new (1.1.8)

Adds first-run onboarding: guidance on FROST key shares and a sign-policy choice during setup. Also brings the app listing screenshots. No other functional changes.

Versions

Version Date Size Requires Android Download
1.1.8 current
919b70a76a9b4b87…
2026-07-12 26 MB API 33
1.1.8
7729240c2c61f6b8…
2026-07-12 24 MB API 33
1.1.7
7c7708d164bb6c70…
2026-07-11 26 MB API 33
1.1.7
498528de9e32757b…
2026-07-11 24 MB API 33

Permissions

What the app asks the system for. Android only grants sensitive access after you confirm it.

  • Internet accessSend and receive data over the internet.
  • BiometricsUnlock with fingerprint or face.
  • CameraTake photos and videos.
  • Run at startupStart automatically after the device is switched on.
  • Network stateCheck whether and how the device is connected.
  • Foreground serviceKeep running in the background, visible in the status bar.
  • FOREGROUND_SERVICE_SPECIAL_USE
  • NotificationsShow notifications.
Show 3 more permissions
  • USE_FULL_SCREEN_INTENT
  • FingerprintUnlock with a fingerprint.
  • keep.DYNAMIC_RECEIVER_NOT_EXPORTED_PERMISSION

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