Face ID and Touch ID Authentication using Swift

biometrics.swift

func authenticate(){
  let context = LAContext()
  let reason = "We need this to protect your payments." // add your own message explaining why you need this authentication method
 
  var authError: NSError?
      if context.canEvaluatePolicy(.deviceOwnerAuthenticationWithBiometrics, error: &authError) {
          context.evaluatePolicy(.deviceOwnerAuthenticationWithBiometrics, localizedReason: reason) { success, error in
              if success {
                  // User authenticated successfully
              } else {
                  // User did not authenticate successfully
              }
          }
      } else {
         // Handle Error
      }
   }
}