FwKnop-ng is an Android client for <a href="https://www.cipherdyne.org/fwknop/">fwknop</a> (Single Packet Authorization). It sends an encrypted, authenticated SPA packet that makes a fwknopd server open a firewall port for your IP address. <b>Features</b> <ul> <li>Rijndael (AES) and GPG (via OpenKeychain) encryption, HMAC authentication</li> <li>Configurations stored encrypted (Android Keystore, Tink, SQLCipher)</li> <li>Optional app lock (biometrics or device credential)</li> <li>Encrypted backup and restore of all configurations</li> <li>Import/export of configurations through QR codes</li> <li>NFC tag triggered knocks</li> </ul> <b>Note:</b> configurations are bound to the device's Android Keystore. Removing the screen lock or a factory reset makes them unrecoverable: keep your fwknop keys elsewhere, or use the encrypted backup.