How to Obfuscate Java Code in Android Apps

Last updated April 7, 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 Obfuscate App Logic in Android apps.

What is Java Code in Android Apps?

Java is a programming language used in mobile app development for building Android apps. Java code consists of human-readable instructions that define the app’s functionality. These instructions use clear terms like “if,” “for,” and meaningful names for methods (functions) and variables (data holders). However, during the build process, this Java code gets compiled into bytecode, a lower-level language understood by the Java Virtual Machine (JVM), an intermediate format that the Android system interprets. Bytecode offers no protection, making it highly susceptible to reverse engineering by tools such as Smali and JADX, which take the Java source code and decompile it into a readable format that allows attackers to examine an app’s functionality and behavior. This can be risky, especially for apps that handle sensitive data or have unique algorithms.

Why Does Java Need it's Own Obfuscation?

Once an attacker has access to the .dex files (containing the bytecode), they can potentially reverse-engineer the logic behind your app and expose your intellectual property and core functionalities. Obfuscation is a security technique that deliberately obscures the internal workings of your code without affecting its functionality. Appdome’s Obfuscate App Logic feature involves renaming methods, functions, variables, and classes within the bytecode. These originally clear and descriptive names are replaced with cryptic characters, making it significantly more challenging to understand the app’s logic by simply looking at the bytecode. This process is essential in preventing attackers from using static code analysis to dissect the application’s functionality, ensuring the security and integrity of the app’s business logic, and protecting intellectual property. Through obfuscation, developers can significantly mitigate the risks associated with code tampering and piracy, preserving the application’s reliability and user trust.

In addition to Obfuscate App Logic, app developers can choose to enforce Appdome’s Dex File Encryption feature. However, it is important to note that Dex File Encryption may cause latency issues. To reduce the latency, we recommend managing the amount of code you’re encrypting.

Prerequisites for Using Appdome's Obfuscate App Logic Plugins:

To use Appdome’s mobile app security build system to Obfuscate App Logic , you’ll need:

How to Implement Obfuscate App Logic in Android Apps Using Appdome

On Appdome, follow these 3 simple steps to create self-defending Android Apps that Obfuscate App Logic 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. Obfuscate App Logic is compatible with: Java, JS, C++, C#, Kotlin, Flutter, React Native, Unity, Xamarin, Cordova and other Android apps.
  2. Select the defense: Obfuscate App Logic.

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

        Figure 1: Fusion Set that will contain the Obfuscate App Logic feature

      2. Follow the steps in Sections 2.2-2.2.2 of this article to add the Obfuscate App Logic feature to your Fusion Set via the Appdome Console.

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

        Fusion Set applied Obfuscate App Logic

        Figure 2: Fusion Set that displays the newly added Obfuscate App Logic 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 Obfuscate App Logic feature to your security template.

      1. Navigate to Build > Security tab > TOTALCode™ Obfuscation section in the Appdome Console.
      2. Toggle On > Obfuscate App Logic.
        Obfuscate App Logic option

        Figure 4: Selecting Obfuscate App Logic

    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 Obfuscate App Logic protection is now added to the mobile app
  3. Certify the Obfuscate App Logic feature in Android Apps

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

Using Threat-Events™ for App Logic Intelligence and Control in Android Apps

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

The specifications and options for Threat-Events™ for App Logic are:

Threat-Event™ Elements Obfuscate App Logic Method Detail
Appdome Feature Name Obfuscate App Logic
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 Obfuscating App Logic 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 App Logic is detected.


The following is a code sample for native Android apps, which uses all values in the specification above for Obfuscate App Logic:


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 Obfuscate App Logic. 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 Obfuscate App Logic

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 to Obfuscate Kotlin Code in Android Apps

Obfuscate Mobile Business Logic, Anti-Reversing in Android Apps

Dex Relocation, Anti-Reversing for 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.

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