How to Optimize File Size when Obfuscating Android Apps

Last updated December 5, 2023 by Appdome

This Knowledge Base article describes how to use Appdome’s AI/ML in your CI/CD pipeline to continuously deliver plugins that Prevent obfuscation of publicly available components in Android apps.

Why Prevent Obfuscation of Publicly Available Components?

Obfuscation reduces the efficiency of compression algorithms; therefore, obfuscating all the code in the app may significantly increase its file size. On the other hand, excluding publicly available elements from obfuscation decreases the size of the built app.

Which Libraries are Excluded from Obfuscation?

If you enable Favor App Size, the following libraries will remain deobfuscated:

Open Source Libraries:

Libraries Comment
libstlport_shared.so https://developer.android.com/ndk/guides/cpp-support
libiconv.so, libzbarjni.so https://github.com/dm77/ZBarScanner
libtool-checker.so https://github.com/scottyab/rootbeer
libcrashlytics.so, libcrashlytics-envelope.so https://try.crashlytics.com/sdk-android
libfirebase.so https://github.com/firebase/firebase-android-sdk
libmpdf.so https://github.com/mpdf/mpdf
libj2v8.so https://github.com/eclipsesource/J2V8
libjniPdfium.so, libmodpdfium.so https://pdfium.googlesource.com/pdfium
libopencv_imgproc.so, libopencv_core.so, libopencv_java3.so https://opencv.org

Xamarin Libraries

libmonodroid.so, libmono-btls-shared.so, libmonosgen-2.0.so, libe_sqlite3.so

React Native

libfb.so, libfolly_json.so, libglog.so, libglog_init.so, libgnustl_shared.so, libicu_common.so, libimagepipeline.so, libjsc.so, libprivatedata.so, libreactnativejni.so, libyoga.so. libc++_shared.so

Unity

libunity.so, libil2cpp.so, libcri_ware_unity.so, libgpg.so

Cordova

libxwalkcore.so, libxwalkdummy.so, libsqlcipher.so

IMPORTANT: Some applications which come with anti-tampering might clash with Appdome’s binary code obfuscation. Read this article to learn more about Appdome’s Anti-Tampering functionality.

Prerequisites for Using Appdome's Favor App's Size Plugins:

To use Appdome’s mobile app security build system to Prevent obfuscation of publicly available components , you’ll need:

How to Implement Prevent obfuscation of publicly available components in Android Apps Using Appdome

On Appdome, follow these 3 simple steps to create self-defending Android Apps that Prevent obfuscation of publicly available components 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. Android Formats: .apk or .aab
    3. Favor App's Size is compatible with: Java, JS, C++, C#, Kotlin, Flutter, React Native, Unity, Xamarin, Cordova and other Android apps.
  2. Select the defense: Favor App's Size.

      1. Create and name the Fusion Set (security template) that will contain the Favor App's Size feature as shown below:
        fusion set that contains Favor App's Size

        Figure 1: Fusion Set that will contain the Favor App's Size feature

      2. Follow the steps in Sections 2.2-2.2.2 of this article to add the Favor App's Size feature to your Fusion Set via the Appdome Console.

      3. When you select the Favor App's Size you'll notice that the Fusion Set you created in step 2.1 now bears the icon of the protection category that contains Favor App's Size.

        Fusion Set applied Favor App's Size

        Figure 2: Fusion Set that displays the newly added Favor App's Size 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 Favor App's Size feature to your security template.

      1. Navigate to Build > Security tab > TOTALCode™ Obfuscation section in the Appdome Console.
      2. Toggle On > Favor App's Size.
        Favor App's Size option

        Figure 4: Selecting Prevent obfuscation of publicly available components

    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 Favor App's Size protection is now added to the mobile app
  3. Certify the Favor App's Size feature in Android Apps

    After building Favor App's Size, Appdome generates a Certified Secure™ certificate to guarantee that the Favor App's Size protection has been added and is protecting the app. To verify that the Favor App's Size protection has been added to the mobile app, locate the protection in the Certified Secure™ certificate as shown below: Favor App's Size 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 Favor App's Size has been added to each Android app. Certified Secure provides instant and in-line DevSecOps compliance certification that Favor App's Size and other mobile app security features are in each build of the mobile app.

Using Threat-Events™ for obfuscation of publicly available components Intelligence and Control in Android Apps

Appdome Threat-Events™ provides consumable in-app mobile app attack intelligence and defense control when obfuscation of publicly available components is detected. To consume and use Threat-Events™ for obfuscation of publicly available components in Android Apps, use registerReceiver in the Application OnCreate, and the code samples for Threat-Events™ for obfuscation of publicly available components shown below.

The specifications and options for Threat-Events™ for obfuscation of publicly available components are:

Threat-Event™ Elements Prevent obfuscation of publicly available components Method Detail
Appdome Feature Name Favor App's Size
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 Preventing obfuscation of publicly available components 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.
carrierPlmn PLMN of the device. Only available for Android devices.
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
carrierName Carrier name of the current device. Only available for Android.
updatedOSVersion Is the OS version up to date
deviceBrand Brand of the device
deviceBoard Board of the device
buildUser Build user
buildHost Build host
sdkVersion Sdk version
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), Android developers can get detailed attack intelligence and granular defense control in Android applications and create amazing user experiences for all mobile end users when obfuscation of publicly available components is detected.


The following is a code sample for native Android apps, which uses all values in the specification above for Favor App's Size:


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.



Using Appdome, there are no development or coding prerequisites to build secured Android Apps by using Favor App's Size. 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 Favor App's Size

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:

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.

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