Enable or Disable Biometric Authentication from Settings
The peer mentor must have agency over whether biometric authentication is active on their device. During onboarding after first login, they should be prompted to enable biometrics with a clear explanation of what it does. They should also be able to revisit this setting at any time through the app settings. Disabling biometrics should immediately revoke the stored biometric session credential from secure storage and require full password or BankID login on the next session.
User Story
Audience Summaries
Giving peer mentors direct control over biometric authentication is a strategic trust and compliance requirement for NHF and its partner organizations. Peer mentors often work in sensitive environments — supporting vulnerable populations — and may share devices in family or organizational settings. By providing a transparent opt-in/opt-out mechanism during onboarding and in settings, the app demonstrates respect for user autonomy, which is a core driver of adoption among this demographic. Failure to provide this control creates support escalations, erodes trust, and risks non-compliance with WCAG 2.2 AA user control principles.
High-priority implementation directly supports user retention, organizational credibility, and positions the platform as a trustworthy digital companion for peer support work across all four partner organizations.
This high-priority story spans authentication UX, secure storage management, and settings UI, requiring coordination between frontend, security, and QA. The onboarding prompt must be delivered after first successful login, meaning sequencing with the authentication flow is a critical dependency (story-biometric-session-authentication-peer-mentor-001). Development effort includes the prompt screen, settings toggle, and the secure storage revocation logic. Acceptance criteria are clearly defined — six scenarios covering onboarding, in-settings toggling, revocation, fallback enforcement, and state reflection — which makes UAT planning straightforward.
Risk areas include device-specific secure storage APIs and ensuring the toggle state persists correctly across sessions. Rollout should include regression testing on both iOS and Android to confirm biometric credential removal is immediate and complete when toggled off.
Implementation requires integrating with the platform's secure storage API (e.g., Keychain on iOS, Keystore on Android) to store and revoke biometric session credentials. The onboarding prompt component must be triggered post-first-login and should check whether biometric hardware and enrollment are available before displaying options. The settings screen needs a toggle component bound to a persisted user preference (local secure store or user profile). On toggle-off, the credential deletion must be synchronous and confirmed before UI state updates.
On toggle-on, the OS biometric enrollment prompt must be invoked and only write the credential on success. Edge cases include: toggle state mismatch after app reinstall, credential deletion failure handling, and OS-level biometric changes (e.g., new fingerprint added). Unit tests should cover all six acceptance criteria scenarios, including state persistence across cold app restarts.
Acceptance Criteria
- Given I complete first-time login successfully, When I reach the biometric setup prompt, Then I am shown a clear explanation of what biometric login does, with options to enable or skip
- Given I chose to skip biometric setup during onboarding, When I open the app settings later, Then I can find a 'Biometric Login' toggle and enable it at any time
- Given I have biometric authentication enabled, When I toggle it off in settings, Then my biometric session credential is removed from secure storage immediately
- Given I have disabled biometric auth, When I next open the app, Then I am required to authenticate via password or BankID/Vipps
- Given I toggle biometric auth on in settings, When the system biometric prompt appears to confirm setup, Then successfully enrolling stores my session credential in secure storage
- Given biometric auth setup, When I view the settings screen, Then the toggle clearly reflects the current enabled/disabled state
Business Value
User control over security settings is an accessibility and trust requirement. Peer mentors working with vulnerable populations may share devices in family settings or have organizational security requirements. Providing a clear opt-in/opt-out mechanism builds trust, satisfies WCAG 2.2 AA user control principles, and prevents support escalations caused by biometric configurations users do not understand or want.
Components
- Biometric Authentication Screen ui
- Biometric Authentication Service service
- Local Auth Integration infrastructure
- Secure Session Storage data
- Secure Storage Adapter infrastructure
- Session Resume Manager service
- Biometric Authentication Service service