How to Build Enhanced App Screen Blur iOS Apps

Last updated March 24, 2024 by Appdome

This Knowledge Base article describes how to use Appdome’s AI/ML in your CI/CD pipeline to continuously deliver plugins that Blur Focus Loss in iOS apps.

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 Appdome's Blur on Focus Loss Plugins:

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)

How to Implement Blur Focus Loss in 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:

Designate the Mobile App to be protected.
1. Upload an app via the Appdome Mobile Defense platform GUI or via Appdome’s DEV-API or CI/CD Plugins.
2. iOS Formats: .ipa
3. Blur on Focus Loss is compatible with: Obj-C, Java, Swift, Flutter, React Native, Unity, Xamarin, Cordova and other iOS apps.
Select the defense: Blur on Focus Loss.

Create and name the Fusion Set (security template) that will contain the Blur on Focus Loss feature as shown below:

Figure 1: Fusion Set that will contain the Blur on Focus Loss feature

Follow the steps in Sections 2.2-2.2.2 of this article to add the Blur on Focus Loss feature to your Fusion Set via the Appdome Console.

When you select the Blur on Focus Loss you'll notice that the Fusion Set you created in step 2.1 now bears the icon of the protection category that contains Blur on Focus Loss.

Figure 2: Fusion Set that displays the newly added Blur on Focus Loss protection
Note: Annotating the Fusion Set to identify the protection(s) selected is optional only (not mandatory).

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 3: Fusion Set Detail Summary

Follow the instructions below to use the Fusion Set ID inside any standard mobile DevOps or CI/CD toolkit like Bitrise, Jenkins, Travis, Team City, Circle CI or other system:

Refer to the Appdome API Reference Guide for API building instructions.

Look for sample APIs in Appdome’s GitHub Repository.

Add the Blur on Focus Loss feature to your security template.

Navigate to Build > Security tab > Mobile Privacy section in the Appdome Console.
Like all other options in ONEShield™, Blur on Focus Loss is turned on by default, as shown below:
Figure 4: Selecting Blur on Focus Loss
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.

Toggle On > Blur on Focus Loss.

Figure 4: Selecting Blur Focus Loss

Initiate the build command either by clicking Build My App at the bottom of the Build Workflow (shown in Figure 4) or via your CI/CD as described in Section 2.1.4.

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

failSafeEnforce Timed enforcement against the identified threat

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.

deviceID Current device ID

reasonCode Reason code of the occurred event

buildDate Appdome fusion date of the current application

devicePlatform OS 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

threatCode The last six characters of the threat code specify the OS, allowing the Threat Resolution Center to address the attack on the affected device.

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:

Important! Replace all placeholder instances of <Context Key> with the specific name of your threat event context key across all language examples. This is crucial to ensure your code functions correctly with the intended event data. For example, The <Context Key> could be the message, externalID, OS Version, reason code, etc.

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 // Current threat event score let currentThreatEventScore = usrInf["currentThreatEventScore"]; // Total threat events score let threatEventsScore = usrInf["threatEventsScore"]; // Replace '' with your specific event context key // let variable = usrInf[""]; // Your logic goes here (Send data to Splunk/Dynatrace/Show Popup...) }

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

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

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

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 // Current threat event score var currentThreatEventScore = userinfo["currentThreatEventScore"] // Total threat events score var threatEventsScore = userinfo["threatEventsScore"] // Replace '' with your specific event context key // var variable = userinfo[""] // Your logic goes here (Send data to Splunk/Dynatrace/Show Popup...) ); }

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

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 // Current threat event score String currentThreatEventScore = intent.GetStringExtra("currentThreatEventScore"); // Total threat events score String threatEventsScore = intent.GetStringExtra("threatEventsScore"); // Replace '' with your specific event context key // String variable = intent.GetStringExtra(""); // Your logic goes here (Send data to Splunk/Dynatrace/Show Popup...) } }

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

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

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

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 // Current threat event score var currentThreatEventScore = userInfo.currentThreatEventScore // Total threat events score var threatEventsScore = userInfo.threatEventsScore // Replace '' with your specific event context key // var variable = userInfo. // Your logic goes here (Send data to Splunk/Dynatrace/Show Popup...) });

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

import 'dart:async'; import 'package:flutter/material.dart'; import 'package:flutter/services.dart'; class PlatformChannel extends StatefulWidget { const PlatformChannel({super.key}); @override State createState() => _PlatformChannelState(); } class _PlatformChannelState extends State { // Replace with your EventChannel name static const String _eventChannelName = ""; 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 // Current threat event score String currentThreatEventScore = eventData['currentThreatEventScore']; // Total threat events score String threatEventsScore = eventData['threatEventsScore']; // Replace '' with your specific event context key // String variable = eventData['']; }); } // Your logic goes here (Send data to Splunk/Dynatrace/Show Popup...) }

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

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.

Related Articles:

How to Protect Android Apps from Screen Sharing Malware

How to Protect Android & iOS Apps from Keylogging Attacks

How to Protect Floating Windows and Dynamic Content in Android Apps

How Do I Learn More?

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 Appdome's Blur on Focus Loss Plugins:

How to Implement Blur Focus Loss in iOS Apps Using Appdome

Designate the Mobile App to be protected.

Upload an app via the Appdome Mobile Defense platform GUI or via Appdome’s DEV-API or CI/CD Plugins.

Select the defense: Blur on Focus Loss.

Add the Blur on Focus Loss feature to your security template.

Certify the Blur on Focus Loss feature in iOS Apps

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

Related Articles:

How Do I Learn More?

Thank you!

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Supercharge the Experience in Mobile App Defense

Better User Experience in Mobile Defense

Shifting Dynamics in Mobile Fraud Prevention: A Call for Developer Responsibility

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
failSafeEnforce	Timed enforcement against the identified threat
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.
deviceID	Current device ID
reasonCode	Reason code of the occurred event
buildDate	Appdome fusion date of the current application
devicePlatform	OS 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
threatCode	The last six characters of the threat code specify the OS, allowing the Threat Resolution Center to address the attack on the affected device.