Authentication Flow

[cvarjao]

Users can have a few options on how they want to authenticate and unlock the wallet app:

• Biometrics means use of Face recognition or fingerprint reading provided by the OS
• App PIN is an PIN managed from within the app itself (separated from the device security PIN)
• Salt (or key salt) is random data that is used as an additional input to a one-way function that hashes data, a password or passphrase.
• Wallet Encryption Key

Authentication Options

App PIN

A PIN is mandatory for generating a wallet key with entropy provided by the user

Biometrics AND App PIN

The user is required to first unlock with biometrics and also provide the app PIN

Biometrics with App PIN fallback

The user is required to authenticate using biometrics. In the case biometrics authentication fails, or the user decides to cancel biometrics, the user is then prompted by the app PIN to authenticate

Wallet encryption key derivation

The wallet encryption key is derived from the user App PIN + SALT. When biometrics is enabled, the key is stored in a secure storage protected with device biometrics unlock
The SALT is auto-generated (random) and stored in a secure storage provided by the OS
The resulted encryption key is then stored in a secure storage so that it can be retrieved when using just biometrics unlock