Require Face ID to open the app and to send

apps/ios/Koins/AppModel.swift

@@ -15,6 +15,18 @@ final class AppModel: ObservableObject {
   @Published var moneroReady = false
   @Published var moneroAddress: String?
   @Published var moneroAccounts: [MoneroAccount] = []
+  /// Whether the app is behind the biometric lock screen right now.
+  @Published var locked = false
+
+  /// Face ID/Touch ID lock. On by default when the device has biometrics;
+  /// persisted across launches.
+  var faceIDEnabled: Bool {
+    get { UserDefaults.standard.object(forKey: "koins.faceID") as? Bool ?? true }
+    set {
+      UserDefaults.standard.set(newValue, forKey: "koins.faceID")
+      objectWillChange.send()
+    }
+  }
   /// Rough time remaining for the Monero sync, derived from observed block rate.
   @Published var syncEta: String?
 
@@ -41,6 +53,22 @@ final class AppModel: ObservableObject {
 
   var symbol: String { chain.symbol }
 
+  // MARK: - Biometric lock
+
+  func authenticate() async {
+    if await Biometrics.authenticate(reason: "Unlock Koins") {
+      locked = false
+    }
+  }
+
+  /// Requires biometrics for sensitive actions when the lock is enabled; a
+  /// device without biometrics is not asked (the wallet is still usable).
+  func requireAuth(reason: String) async throws {
+    guard faceIDEnabled, Biometrics.isAvailable else { return }
+    let ok = await Biometrics.authenticate(reason: reason)
+    if !ok { throw XRPError.rpc("Authentication failed") }
+  }
+
   // MARK: - Cache
 
   /// Restores the last-known state for the chain on screen instantly; the
@@ -78,6 +106,9 @@ final class AppModel: ObservableObject {
     if xrpWallet != nil || moneroReady {
       chain = xrpWallet != nil ? .xrp : .xmr
     }
+    if xrpWallet != nil || xmrWallet != nil, faceIDEnabled, Biometrics.isAvailable {
+      locked = true
+    }
     showCached(chain)
     await refresh(force: true)
     startAutoRefresh()
@@ -334,6 +365,7 @@ final class AppModel: ObservableObject {
   }
 
   func revealSeed() async throws -> String {
+    try await requireAuth(reason: "Reveal your recovery phrase")
     if chain == .xrp {
       guard let seed = WalletStore.secret(.xrp) else {
         throw XRPError.rpc("No stored secret for this wallet")
@@ -347,6 +379,7 @@ final class AppModel: ObservableObject {
   // MARK: - Sends
 
   func send(to: String, amount: String, tag: String, priority: TransactionPriority) async throws {
+    try await requireAuth(reason: "Authorize this payment")
     let destinationTag = UInt32(tag.trimmingCharacters(in: .whitespaces))
     if chain == .xrp {
       guard let seed = WalletStore.secret(.xrp) else {