Require Face ID to open the app and to send

apps/ios/Koins/Views/LockScreen.swift

@@ -0,0 +1,30 @@
+import SwiftUI
+
+/// Full-screen biometric lock, overlaid on the app whenever `model.locked`.
+struct LockScreen: View {
+  var unlock: () -> Void
+
+  var body: some View {
+    ZStack {
+      Theme.background.ignoresSafeArea()
+      VStack(spacing: 16) {
+        Spacer()
+        Image(systemName: "lock.shield")
+          .font(.system(size: 44, weight: .light))
+          .foregroundStyle(Theme.accent)
+        Text("Koins is locked")
+          .font(.system(size: 22, weight: .bold))
+          .foregroundStyle(Theme.text)
+        Text("Authenticate to continue")
+          .font(.system(size: 13))
+          .foregroundStyle(Theme.muted)
+        Spacer()
+        PrimaryButton(title: "Unlock with \(Biometrics.label)", action: unlock)
+        Spacer()
+      }
+      .padding(24)
+    }
+    .preferredColorScheme(.dark)
+    .task { unlock() }
+  }
+}

apps/ios/Koins/Views/RootView.swift

@@ -59,6 +59,13 @@ struct RootView: View {
       .scrollDismissesKeyboard(.interactively)
     }
     .preferredColorScheme(.dark)
+    .overlay {
+      if model.locked, model.faceIDEnabled {
+        LockScreen {
+          Task { await model.authenticate() }
+        }
+      }
+    }
     .task { await model.bootstrap() }
     .sheet(item: $seedBox) { box in
       SeedRevealView(seed: box.seed, symbol: box.symbol) { seedBox = nil }
@@ -67,6 +74,9 @@ struct RootView: View {
       if route == .dashboard { route = .home }
     }
     .onChange(of: scenePhase) { phase in
+      if phase == .background, model.faceIDEnabled, Biometrics.isAvailable {
+        model.locked = true
+      }
       if phase != .active {
         Task { await model.persistWallet() }
       }
@@ -79,6 +89,7 @@ struct HomeView: View {
   @Binding var route: Route
   @State private var showDeleteConfirm = false
   @State private var selectedTransaction: TransactionRecord?
+  @State private var showSettings = false
 
   var body: some View {
     VStack(spacing: 18) {
@@ -104,6 +115,10 @@ struct HomeView: View {
                             symbol: model.symbol,
                             chain: model.chain) { selectedTransaction = nil }
     }
+    .sheet(isPresented: $showSettings) {
+      SettingsView()
+        .environmentObject(model)
+    }
     .confirmationDialog("Delete this wallet?",
                         isPresented: $showDeleteConfirm,
                         titleVisibility: .visible) {
@@ -120,13 +135,26 @@ struct HomeView: View {
   }
 
   private var header: some View {
-    VStack(alignment: .leading, spacing: 4) {
-      Text("Koins")
-        .font(.system(size: 30, weight: .heavy))
-        .foregroundStyle(Theme.text)
-      Text("Monero and XRP wallet")
-        .font(.system(size: 13))
-        .foregroundStyle(Theme.muted)
+    HStack(alignment: .firstTextBaseline) {
+      VStack(alignment: .leading, spacing: 4) {
+        Text("Koins")
+          .font(.system(size: 30, weight: .heavy))
+          .foregroundStyle(Theme.text)
+        Text("Monero and XRP wallet")
+          .font(.system(size: 13))
+          .foregroundStyle(Theme.muted)
+      }
+      Spacer()
+      Button {
+        showSettings = true
+      } label: {
+        Image(systemName: "gearshape")
+          .font(.system(size: 17, weight: .medium))
+          .foregroundStyle(Theme.muted)
+          .frame(width: 36, height: 36)
+          .background(Theme.surface)
+          .clipShape(Circle())
+      }
     }
     .frame(maxWidth: .infinity, alignment: .leading)
   }

apps/ios/Koins/Views/SettingsView.swift

@@ -0,0 +1,44 @@
+import SwiftUI
+
+struct SettingsView: View {
+  @EnvironmentObject private var model: AppModel
+  @Environment(\.dismiss) private var dismiss
+
+  var body: some View {
+    ZStack {
+      Theme.background.ignoresSafeArea()
+      VStack(alignment: .leading, spacing: 18) {
+        ScreenHeader(title: "Settings", subtitle: "Security and device options", onBack: { dismiss() })
+
+        Card {
+          Toggle(isOn: Binding(get: { model.faceIDEnabled },
+                               set: { model.faceIDEnabled = $0 })) {
+            VStack(alignment: .leading, spacing: 3) {
+              Text("Unlock with \(Biometrics.label)")
+                .font(.system(size: 15, weight: .semibold))
+                .foregroundStyle(Theme.text)
+              Text("Require \(Biometrics.label) to open the app, reveal the recovery phrase, and send payments.")
+                .font(.system(size: 11))
+                .foregroundStyle(Theme.muted)
+            }
+          }
+          .tint(Theme.accent)
+          .disabled(!Biometrics.isAvailable)
+
+          if !Biometrics.isAvailable {
+            Text("This device has no biometric sensor configured.")
+              .font(.system(size: 11))
+              .foregroundStyle(Theme.muted)
+          }
+        }
+
+        Spacer(minLength: 0)
+      }
+      .padding(.horizontal, 20)
+      .padding(.top, 12)
+    }
+    .preferredColorScheme(.dark)
+    .presentationDetents([.medium])
+    .presentationDragIndicator(.visible)
+  }
+}