How to Obfuscate SelRefs in Obj-C Using AI

Last updated March 12, 2025 by Appdome

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

What Are iOS SelRefs?

iOS SelRef (Selector Reference) obfuscation is a technique used to protect the selectors that link method names to their implementations in an iOS app’s compiled binary. In the Objective-C runtime, method names are converted into selectors (SelRefs) during compilation. Attackers commonly target these SelRefs during static analysis to reverse-engineer or understand the app’s internal logic. By identifying which method is associated with a specific SelRef, they can deduce the functionality of certain methods, enabling them to exploit vulnerabilities or replicate app behavior. SelRef obfuscation scrambles or hides these selector references, making it extremely difficult for attackers to map method names and understand the app’s logic. This technique is essential for protecting intellectual property and meeting compliance standards that require securing proprietary software logic. Obfuscating SelRefs strengthens app defenses against unauthorized code access, ensuring method functionality remains secure and hidden from tampering.

How Appdome Protects Mobile Apps with SelRef Obfuscation?

Appdome’s iOS SelRef Obfuscation plugin automatically obfuscates the selector references in an iOS application’s binary. This protection ensures that attackers cannot use static analysis or reverse engineering tools to resolve the SelRefs back to their corresponding method names. By preventing this linkage, Appdome significantly reduces the risk of exposing critical application logic and makes it far more challenging for malicious actors to gain insights into how the app functions. This feature integrates seamlessly into the app without requiring any additional coding, providing a powerful layer of protection against reverse engineering attempts.

Prerequisites for Using Appdome's Obj-C SelRef Obfuscation Plugins:

To use Appdome’s mobile app security build system to Add SelRef Obfuscation , you’ll need:

How to Implement Add SelRef Obfuscation in iOS Apps Using Appdome

On Appdome, follow these 3 simple steps to create self-defending iOS Apps that Add SelRef Obfuscation without an SDK or gateway:

  1. 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. Obj-C SelRef Obfuscation is compatible with: Obj-C, Java, Swift, Flutter, React Native, Unity, Xamarin, Cordova and other iOS apps.
  2. Select the defense: Obj-C SelRef Obfuscation.

      1. Create and name the Fusion Set (security template) that will contain the Obj-C SelRef Obfuscation feature as shown below:
        fusion set that contains Obj-C SelRef Obfuscation

        Figure 1: Fusion Set that will contain the Obj-C SelRef Obfuscation feature

      2. Follow the steps in Sections 2.2-2.2.2 of this article to add the Obj-C SelRef Obfuscation feature to your Fusion Set via the Appdome Console.

      3. When you select the Obj-C SelRef Obfuscation you'll notice that the Fusion Set you created in step 2.1 now bears the icon of the protection category that contains Obj-C SelRef Obfuscation.

        Fusion Set applied Obj-C SelRef Obfuscation

        Figure 2: Fusion Set that displays the newly added Obj-C SelRef Obfuscation protection
        Note: Annotating the Fusion Set to identify the protection(s) selected is optional only (not mandatory).

      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 3: Fusion Set Detail Summary

      5. 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:
        1. Refer to the Appdome API Reference Guide for API building instructions.
        2. Look for sample APIs in Appdome’s GitHub Repository.
    1. Add the Obj-C SelRef Obfuscation feature to your security template.

      1. Navigate to Build > Security tab > TOTALCode™ Obfuscation section in the Appdome Console.
      2. Toggle On Obj-C SelRef Obfuscation.
        Obj-C SelRef Obfuscation option

        Figure 4: Selecting Add SelRef Obfuscation

        Note: The Appdome Platform displays the Mobile Operation Systems supported by each defense in real-time. For more details, see our OS Support Policy KB.

      3. Configure the User Experience Options for Obj-C SelRef Obfuscation:
        With Threat-Events™ OFF, Appdome provides several user experience options for mobile brands and developers.
        1. App Compromise Notification: Customize the pop-up or toast Appdome uses to notify the user when a threat is present while using the protected mobile app.
        2. Short message Option. This is available for mobile devices that allow a banner notification for security events.
        3. Localized Message Option. Allows Appdome users to support global languages in security notifications.

          Localized Message

          Figure 5: Default User Experience Options for Appdome’s SelRef Obfuscation

        4. Obj-C SelRef Obfuscation Threat Code™. Appdome uses AI/ML to generate a unique code each time Obj-C SelRef Obfuscation is triggered by an active threat on the mobile device. Use the code in Appdome Threat Resolution Center™ to help end users identify, find and resolve active threats on the personal mobile devices.
    2. 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 Obj-C SelRef Obfuscation protection is now added to the mobile app
  3. Certify the Obj-C SelRef Obfuscation feature in iOS Apps

    After building Obj-C SelRef Obfuscation, Appdome generates a Certified Secure™ certificate to guarantee that the Obj-C SelRef Obfuscation protection has been added and is protecting the app. To verify that the Obj-C SelRef Obfuscation protection has been added to the mobile app, locate the protection in the Certified Secure™ certificate as shown below: Obj-C SelRef Obfuscation shown in Certificate secure

    Figure 6: 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 Obj-C SelRef Obfuscation has been added to each iOS app. Certified Secure provides instant and in-line DevSecOps compliance certification that Obj-C SelRef Obfuscation and other mobile app security features are in each build of the mobile app.


Using Appdome, there are no development or coding prerequisites to build secured iOS Apps by using Obj-C SelRef Obfuscation. 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 Obj-C SelRef Obfuscation

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:

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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.

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