How to Build Enhanced App Screen Blur iOS Apps

Last updated March 24, 2024 by Appdome

Learn to Blur Focus Loss in iOS apps, in mobile CI/CD with a Data-Driven DevSecOps™ build system.

What is Blur on Focus Loss?

Appdome’s Blur on Focus Loss builds upon the foundation set by the “Blur Application Screen” function, which blurs the screen of an app when it moves into the background, thus safeguarding sensitive information from being visible in the recent app’s view. Blur of Focus Loss takes this a step further by initiating the blur effect immediately when the app loses focus, rather than waiting until it transitions fully to the background. This timely response ensures that user privacy is protected from the very moment they start to swipe away from the app. It also intelligently manages pop-up windows within the app by applying the blur effect to the screen behind them, thereby enhancing privacy without hindering the user experience.

How Appdome Implements Blur on Focus Loss?

Appdome implements Blur on Focus Loss through a sophisticated mechanism that detects when an app is losing focus in real time, triggering the blur effect instantly to protect user privacy. This implementation is particularly beneficial for apps handling sensitive information, such as financial details, personal data, or confidential communications, as it minimizes the window of opportunity for unauthorized visual access. By blurring the screen as soon as the app begins to transition away from the user’s immediate view, Appdome effectively shields against visual hacking techniques and inadvertent information exposure. The feature offers developers the flexibility to choose how and when the blurring should be applied. With the addition of a sub-toggle within the “Blur Application Screen” settings, developers can opt for this enhanced privacy feature, tailoring the app’s security measures to suit the specific needs and preferences of their user base.

Prerequisites for Using Blur on Focus Loss:

To use Appdome’s mobile app security build system to Blur Focus Loss , you’ll need:

Appdome account (create a free Appdome account here)
A license for Blur on Focus Loss
Mobile App (.ipa for iOS)
Signing Credentials (see Signing Secure Android apps and Signing Secure iOS apps)

Blur Focus Loss on iOS apps using Appdome

On Appdome, follow these 3 simple steps to create self-defending iOS Apps that Blur Focus Loss without an SDK or gateway:

Upload the Mobile App to Appdome.
1. Upload an app to Appdome’s Mobile App Security Build System
2. Upload Method: Appdome Console or DEV-API
3. iOS Formats: .ipa
4. Blur on Focus Loss Compatible With: Obj-C, Java, Swift, Flutter, React Native, Unity, Xamarin, Cordova and more
Build the feature: Blur on Focus Loss.
1. Building Blur on Focus Loss by using Appdome’s DEV-API:
  1. Create and name the Fusion Set (security template) that will contain the Blur on Focus Loss feature as shown below:
  2. Follow the steps in Sections 2.2.1-2.2.2 of this article, Building the Blur on Focus Loss feature via Appdome Console, to add the Blur on Focus Loss feature to this Fusion Set.
  3. Open the Fusion Set Detail Summary by clicking the “...” symbol on the far-right corner of the Fusion Set. Copy the Fusion Set ID from the Fusion Set Detail Summary (as shown below):”
    
    Figure 2: Fusion Set Detail Summary
    Note: Annotating the Fusion Set to identify the protection(s) selected is optional only (not mandatory).
  4. Follow the instructions below to use the Fusion Set ID inside any standard mobile DevOps or CI/CD toolkit like Bitrise, App Center, Jenkins, Travis, Team City, Circle CI or other system:
    
    Build an API for the app – for instructions, see the tasks under Appdome API Reference Guide
    
    Look for sample APIs in Appdome’s GitHub Repository
2. Building the Blur on Focus Loss feature via Appdome Console
  
  To build the Blur on Focus Loss protection by using Appdome Console, follow the instructions below.
  1. Where: Inside the Appdome Console, go to Build > Security Tab > Mobile Privacy section.
    Like all other options in ONEShield™, Blur on Focus Loss is turned on by default, as shown below:
    Figure 3: Blur on Focus Loss option
    Note: The App Compromise Notification contains an easy to follow default remediation path for the mobile app end user. You can customize this message as required to achieve brand specific support, workflow or other messaging.
  2. How: Toggle (turn ON) Blur on Focus Loss, as shown below.
    
    Figure 3: Blur Focus Loss option
  3. When you select the Blur on Focus Loss you'll notice that your Fusion Set you created in step 2.1.1 now bears the icon of the protection category that contains Blur on Focus Loss
    
    Figure 4: Fusion Set that displays the newly added Blur on Focus Loss protection
  4. Click Build My App at the bottom of the Build Workflow (shown in Figure 3).
Congratulations! The Blur on Focus Loss protection is now added to the mobile app
Certify the Blur on Focus Loss feature in iOS Apps.

After building Blur on Focus Loss, Appdome generates a Certified Secure™ certificate to guarantee that the Blur on Focus Loss protection has been added and is protecting the app. To verify that the Blur on Focus Loss protection has been added to the mobile app, locate the protection in the Certified Secure™ certificate as shown below:

Figure 5: Certified Secure™ certificate

Each Certified Secure™ certificate provides DevOps and DevSecOps organizations the entire workflow summary, audit trail of each build, and proof of protection that Blur on Focus Loss has been added to each iOS app. Certified Secure provides instant and in-line DevSecOps compliance certification that Blur on Focus Loss and other mobile app security features are in each build of the mobile app

Using Threat-Events™ for Focus Loss Intelligence and Control in iOS Apps

Appdome Threat-Events™ provides consumable in-app mobile app attack intelligence and defense control when Focus Loss is detected. To consume and use Threat-Events™ for Focus Loss in iOS Apps, use AddObserverForName in Notification Center, and the code samples for Threat-Events™ for Focus Loss shown below.

The specifications and options for Threat-Events™ for Focus Loss are:

Threat-Event™ Elements	Blur Focus Loss Method Detail
Appdome Feature Name	Blur on Focus Loss
Threat-Event Mode
OFF, IN-APP DEFENSE	Appdome detects, defends and notifies user (standard OS dialog) using customizable messaging.
ON, IN-APP DETECTION	Appdome detects the attack or threat and passes the event in a standard format to the app for processing (app chooses how and when to enforce).
ON, IN-APP DEFENSE	Uses Appdome Enforce mode for any attack or threat and passes the event in a standard format to the app for processing (gather intel on attacks and threats without losing any protection).
Certified Secure™ Threat Event Check	x
Visible in ThreatScope™	x
Developer Parameters for Bluring Focus Loss Threat-Event™
Threat-Event NAME
Threat-Event DATA	reasonData
Threat-Event CODE	reasonCode
Threat-Event REF
Threat-Event SCORE
currentThreatEventScore	Current Threat-Event score
threatEventsScore	Total Threat-events score

Threat-Event Context Keys
message	Message displayed for the user on event
externalID	The external ID of the event which can be listened via Threat Events
osVersion	OS version of the current device
deviceModel	Current device model
deviceManufacturer	The manufacturer of the current device
fusedAppToken	The task ID of the Appdome fusion of the currently running app
kernelInfo	Info about the kernel: system name, node name, release, version and machine.
carrierPlmn	PLMN of the device
deviceID	Current device ID
reasonCode	Reason code of the occured event
buildDate	Appdome fusion date of the current application
devicePlatform	OS name of the current device
carrierName	Carrier name of the current device
updatedOSVersion	Is the OS version up to date
timeZone	Time zone
deviceFaceDown	Is the device face down
locationLong	Location longitude conditioned by location permission
locationLat	Location latitude conditioned by location permission
locationState	Location state conditioned by location permission
wifiSsid	Wifi SSID
wifiSsidPermissionStatus	Wifi SSID permission status

With Threat-Events™ enabled (turned ON), iOS developers can get detailed attack intelligence and granular defense control in iOS applications and create amazing user experiences for all mobile end users when Focus Loss is detected.

The following is a code sample for native iOS apps, which uses all values in the specification above for Blur on Focus Loss:

let center = NotificationCenter.default
                center.addObserver(forName: Notification.Name(""), object: nil, queue: nil) { (note) in
                    guard let usrInf = note.userInfo else {
                        return
                    }

                    let message = usrInf["message"]; // Message shown to the user
                    let reasonData = usrInf["reasonData"]; // Threat detection cause
                    let reasonCode = usrInf["reasonCode"]; // Event reason code
                    let currentThreatEventScore = usrInf["currentThreatEventScore"]; // Current threat event score
                    let threatEventsScore = usrInf["threatEventsScore"]; // Total threat events score
                    let variable = usrInf["<Context Key>"]; // Any other event specific context key

                    // Your logic goes here (Send data to Splunk/Dynatrace/Show Popup...)
                }

                         
                        Swift
                    
​x
 
let center = NotificationCenter.default
center.addObserver(forName: Notification.Name(""), object: nil, queue: nil) { (note) in
    guard let usrInf = note.userInfo else {
        return
    }
​
    let message = usrInf["message"]; // Message shown to the user
    let reasonData = usrInf["reasonData"]; // Threat detection cause
    let reasonCode = usrInf["reasonCode"]; // Event reason code
    let currentThreatEventScore = usrInf["currentThreatEventScore"]; // Current threat event score
    let threatEventsScore = usrInf["threatEventsScore"]; // Total threat events score
    let variable = usrInf["<Context Key>"]; // Any other event specific context key
​
    // Your logic goes here (Send data to Splunk/Dynatrace/Show Popup...)
}

[[NSNotificationCenter defaultCenter] addObserverForName:  "" object:nil queue:nil usingBlock:^(NSNotification *org_note) {
                    __block NSNotification *note = org_note;
                    dispatch_async(dispatch_get_main_queue(), ^(void) {
                        NSString *message = [[note userInfo] objectForKey:@"message"]; // Message shown to the user
                        NSString *reasonData = [[note userInfo] objectForKey:@"reasonData"]; // Threat detection cause
                        NSString *reasonCode = [[note userInfo] objectForKey:@"reasonCode"]; // Event reason code
                        NSString *currentThreatEventScore = [[note userInfo] objectForKey:@"currentThreatEventScore"]; // Current threat event score
                        NSString *threatEventsScore = [[note userInfo] objectForKey:@"threatEventsScore"]; // Total threat events score
                        NSString *variable = [[note userInfo] objectForKey:@"<Context Key>"]; // Any other event specific context key

                        // Your logic goes here (Send data to Splunk/Dynatrace/Show Popup...)
                    });
                }];

                         
                        Objective-C
                    
​x
 
[[NSNotificationCenter defaultCenter] addObserverForName:  @"" object:nil queue:nil usingBlock:^(NSNotification *org_note) {
    __block NSNotification *note = org_note;
    dispatch_async(dispatch_get_main_queue(), ^(void) {
        NSString *message = [[note userInfo] objectForKey:@"message"]; // Message shown to the user
        NSString *reasonData = [[note userInfo] objectForKey:@"reasonData"]; // Threat detection cause
        NSString *reasonCode = [[note userInfo] objectForKey:@"reasonCode"]; // Event reason code
        NSString *currentThreatEventScore = [[note userInfo] objectForKey:@"currentThreatEventScore"]; // Current threat event score
        NSString *threatEventsScore = [[note userInfo] objectForKey:@"threatEventsScore"]; // Total threat events score
        NSString *variable = [[note userInfo] objectForKey:@"<Context Key>"]; // Any other event specific context key
​
        // Your logic goes here (Send data to Splunk/Dynatrace/Show Popup...)
    });
}];

const { ADDevEvents } = NativeModules;
                const aDDevEvents = new NativeEventEmitter(ADDevEvents);

                function registerToDevEvent(action, callback) {
                    NativeModules.ADDevEvents.registerForDevEvent(action);
                    aDDevEvents.addListener(action, callback);
                }

                export function registerToAllEvents() {
                    registerToDevEvent(
                        "",
                        (userinfo) => Alert.alert(JSON.stringify(userinfo))

                        var message = userinfo["message"] // Message shown to the user
                        var reasonData = userinfo["reasonData"] // Threat detection cause
                        var reasonCode = userinfo["reasonCode"] // Event reason code
                        var currentThreatEventScore = userinfo["currentThreatEventScore"] // Current threat event score
                        var threatEventsScore = userinfo["threatEventsScore"] // Total threat events score
                        var variable = userinfo["<Context Key>"] // Any other event specific context key

                        // Your logic goes here (Send data to Splunk/Dynatrace/Show Popup...)
                    );
                }

                     
                    React Native
                
​x
 
const { ADDevEvents } = NativeModules;
const aDDevEvents = new NativeEventEmitter(ADDevEvents);
​
function registerToDevEvent(action, callback) {
    NativeModules.ADDevEvents.registerForDevEvent(action);
    aDDevEvents.addListener(action, callback);
}
​
export function registerToAllEvents() {
    registerToDevEvent(
        "",
        (userinfo) => Alert.alert(JSON.stringify(userinfo))
​
        var message = userinfo["message"] // Message shown to the user
        var reasonData = userinfo["reasonData"] // Threat detection cause
        var reasonCode = userinfo["reasonCode"] // Event reason code
        var currentThreatEventScore = userinfo["currentThreatEventScore"] // Current threat event score
        var threatEventsScore = userinfo["threatEventsScore"] // Total threat events score
        var variable = userinfo["<Context Key>"] // Any other event specific context key
​
        // Your logic goes here (Send data to Splunk/Dynatrace/Show Popup...)
    );
}
​

RegisterReceiver(new ThreatEventReceiver(), new IntentFilter(""));
                class ThreatEventReceiver : BroadcastReceiver
                {
                public override void OnReceive(Context context, Intent intent)
                {
                    String message = intent.GetStringExtra("message"); // Message shown to the user
                    String reasonData = intent.GetStringExtra("reasonData"); // Threat detection cause
                    String reasonCode = intent.GetStringExtra("reasonCode"); // Event reason code
                    String currentThreatEventScore = intent.GetStringExtra("currentThreatEventScore"); // Current threat event score
                    String threatEventsScore = intent.GetStringExtra("threatEventsScore"); // Total threat events score
                    String variable = intent.GetStringExtra("<Context Key>"); // Any other event specific context key

                    // Your logic goes here (Send data to Splunk/Dynatrace/Show Popup...)
                }
                }

                    
                    Xamarin/MAUI Android
                
​x
 
RegisterReceiver(new ThreatEventReceiver(), new IntentFilter(""));
​
class ThreatEventReceiver : BroadcastReceiver
{
  public override void OnReceive(Context context, Intent intent)
  {
    String message = intent.GetStringExtra("message"); // Message shown to the user
    String reasonData = intent.GetStringExtra("reasonData"); // Threat detection cause
    String reasonCode = intent.GetStringExtra("reasonCode"); // Event reason code
    String currentThreatEventScore = intent.GetStringExtra("currentThreatEventScore"); // Current threat event score
    String threatEventsScore = intent.GetStringExtra("threatEventsScore"); // Total threat events score
    String variable = intent.GetStringExtra("<Context Key>"); // Any other event specific context key
​
    // Your logic goes here (Send data to Splunk/Dynatrace/Show Popup...)
  }
}

                NSNotificationCenter.DefaultCenter.AddObserver(
                    (NSString)"JailbrokenDevice", // Threat-Event Identifier
                    delegate (NSNotification notification)
                    {
                        var message = notification.UserInfo.ObjectForKey("message"); // Message shown to the user
                        var reasonData = notification.UserInfo.ObjectForKey("reasonData"); // Threat detection cause
                        var reasonCode = notification.UserInfo.ObjectForKey("reasonCode"); // Event reason code
                        var currentThreatEventScore = notification.UserInfo.ObjectForKey("currentThreatEventScore"); // Current threat event score
                        var threatEventsScore = notification.UserInfo.ObjectForKey("threatEventsScore"); // Total threat events score
                        var variable = notification.UserInfo.ObjectForKey(""); // Any other event specific context key
                        // Your logic goes here (Send data to Splunk/Dynatrace/Show Popup...)
                    });

                    
                    Xamarin/MAUI iOS
                
 
NSNotificationCenter.DefaultCenter.AddObserver(
  (NSString)"", // Threat-Event Identifier
  delegate (NSNotification notification)
  {
    var message = notification.UserInfo.ObjectForKey("message"); // Message shown to the user
    var reasonData = notification.UserInfo.ObjectForKey("reasonData"); // Threat detection cause
    var reasonCode = notification.UserInfo.ObjectForKey("reasonCode"); // Event reason code
    var currentThreatEventScore = notification.UserInfo.ObjectForKey("currentThreatEventScore"); // Current threat event score
    var threatEventsScore = notification.UserInfo.ObjectForKey("threatEventsScore"); // Total threat events score
    var variable = notification.UserInfo.ObjectForKey("<Context Keys>"); // Any other event specific context key
    // Your logic goes here (Send data to Splunk/Dynatrace/Show Popup...)
  });

window.broadcaster.addEventListener("", function(userInfo) {
        var message = userInfo.message // Message shown to the user
        var reasonData = userInfo.reasonData // Threat detection cause
        var reasonCode = userInfo.reasonCode // Event reason code
        var currentThreatEventScore = userInfo.currentThreatEventScore // Current threat event score
        var threatEventsScore = userInfo.threatEventsScore // Total threat events score
        var variable = userInfo.<Context Key> // Any other event specific context key

        // Your logic goes here (Send data to Splunk/Dynatrace/Show Popup...)
            });

                    
                    Cordova
                
​x
 
window.broadcaster.addEventListener("", function(userInfo) {
        var message = userInfo.message // Message shown to the user
        var reasonData = userInfo.reasonData // Threat detection cause
        var reasonCode = userInfo.reasonCode // Event reason code
        var currentThreatEventScore = userInfo.currentThreatEventScore // Current threat event score
        var threatEventsScore = userInfo.threatEventsScore // Total threat events score
        var variable = userInfo.<Context Key> // Any other event specific context key
​
        // Your logic goes here (Send data to Splunk/Dynatrace/Show Popup...)
});

                import 'dart:async';
                import 'package:flutter/material.dart';
                import 'package:flutter/services.dart';

                class PlatformChannel extends StatefulWidget {
                  const PlatformChannel({super.key});

                  @override
                  State<PlatformChannel> createState() => _PlatformChannelState();
                }

                class _PlatformChannelState extends State<PlatformChannel> {
                  static const String _eventChannelName = ""; // Replace with your EventChannel name
                  static const EventChannel _eventChannel = EventChannel(_eventChannelName);

                  @override
                  void initState() {
                    super.initState();
                    _eventChannel.receiveBroadcastStream().listen(_onEvent, onError: _onError);
                  }

                  void _onEvent(Object? event) {
                    setState(() {
                      // Adapt this section based on your specific event data structure
                      var eventData = event as Map;

                      // Example: Accessing 'externalID' field from the event
                      var externalID = eventData['externalID'];

                      // Customize the rest of the fields based on your event structure
                      String message = eventData['message']; // Message shown to the user
                      String reasonData = eventData['reasonData']; // Threat detection cause
                      String reasonCode = eventData['reasonCode']; // Event reason code
                      String currentThreatEventScore = eventData['currentThreatEventScore']; // Current threat event score
                      String threatEventsScore = eventData['threatEventsScore']; // Total threat events score

                      // Any other event specific context key
                      String variable = eventData['<Context Key>'];
                    });
                  }

                  // Your logic goes here (Send data to Splunk/Dynatrace/Show Popup...)
                }

                    
                    Flutter
                
xxxxxxxxxx
 
import 'dart:async';
​
import 'package:flutter/material.dart';
import 'package:flutter/services.dart';
​
class PlatformChannel extends StatefulWidget {
  const PlatformChannel({super.key});
​
  @override
  State<PlatformChannel> createState() => _PlatformChannelState();
}
​
class _PlatformChannelState extends State<PlatformChannel> {
  static const String _eventChannelName = ''; // Replace with your EventChannel name
  static const EventChannel _eventChannel = EventChannel(_eventChannelName);
​
  @override
  void initState() {
    super.initState();
    _eventChannel.receiveBroadcastStream().listen(_onEvent, onError: _onError);
  }
​
  void _onEvent(Object? event) {
    setState(() {
      // Adapt this section based on your specific event data structure
      var eventData = event as Map;
​
      // Example: Accessing 'externalID' field from the event
      var externalID = eventData['externalID'];
​
      // Customize the rest of the fields based on your event structure
      String message = eventData['message']; // Message shown to the user
      String reasonData = eventData['reasonData']; // Threat detection cause
      String reasonCode = eventData['reasonCode']; // Event reason code
      String currentThreatEventScore = eventData['currentThreatEventScore']; // Current threat event score
      String threatEventsScore = eventData['threatEventsScore']; // Total threat events score
​
      // Any other event specific context key
      String variable = eventData['<Context Key>'];
    });
  }
​
  // Your logic goes here (Send data to Splunk/Dynatrace/Show Popup...)
}

Using Appdome, there are no development or coding prerequisites to build secured iOS Apps by using Blur on Focus Loss. There is no SDK and no library to code or implement in the app and no gateway to deploy in your network. All protections are built into each app and the resulting app is self-defending and self-protecting.

Releasing and Publishing Mobile Apps with Blur on Focus Loss

After successfully securing your app by using Appdome, there are several available options to complete your project, depending on your app lifecycle or workflow. These include:

Customizing, Configuring & Branding Secure Mobile Apps
Deploying/Publishing Secure mobile apps to Public or Private app stores
Releasing Secured Android & iOS Apps built on Appdome.

If you have any questions, please send them our way at support.appdome.com or via the chat window on the Appdome platform.

Thank you!

Thanks for visiting Appdome! Our mission is to secure every app on the planet by making mobile app security easy. We hope we’re living up to the mission with your project.

How to Build Enhanced App Screen Blur iOS Apps

What is Blur on Focus Loss?

How Appdome Implements Blur on Focus Loss?

Prerequisites for Using Blur on Focus Loss:

Blur Focus Loss on iOS apps using Appdome

Upload the Mobile App to Appdome.

Upload an app to Appdome’s Mobile App Security Build System

Build the feature: Blur on Focus Loss.

Building Blur on Focus Loss by using Appdome’s DEV-API:

Building the Blur on Focus Loss feature via Appdome Console

Certify the Blur on Focus Loss feature in iOS Apps.

Using Threat-Events™ for Focus Loss Intelligence and Control in iOS Apps

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