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:

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:

  1. 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
  2. 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. fusion set that contains Blur on Focus Loss

        Figure 1: Fusion Set that will contain the Blur on Focus Loss feature
        Note: Naming the Fusion Set to correspond to the protection(s) selected is for illustration purposes only (not required).

      3. 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.

      4. 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):” fusion Set Detail Summary image

        Figure 2: Fusion Set Detail Summary
        Note: Annotating the Fusion Set to identify the protection(s) selected is optional only (not mandatory).

      5. 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:
        1. Build an API for the app – for instructions, see the tasks under Appdome API Reference Guide
        2. 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.
      2. 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

        Fusion Set applied Blur on Focus Loss

        Figure 4: Fusion Set that displays the newly added Blur on Focus Loss protection

      3. 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
  3. 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: Blur on Focus Loss shown in Certificate secure

    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:

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:

Related Articles:

If you have any questions, please send them our way at 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.

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