How to Encrypt Strings.xml in Android Apps

Last updated March 10, 2024 by Appdome

Learn to Encrypt strings under strings.xml in Android apps, in mobile CI/CD with a Data-Driven DevSecOps™ build system.

What is the strings.xml file?

The strings.xml file is the usual location for storing a string resource, which provides text strings for your application, with optional text styling and formatting. Unlike the java strings and the assets folder, the string resources cannot be encrypted on the device because the OS needs to access the strings file. This makes strings the soft belly of any application, as they can contain sensitive information such as phrases, URLs, tokens, and passwords that can be easily understood from the application without using any specialized tools.

How does Appdome Protect the strings.xml File?

To provide customers with overall security protection of their Android app, Appdome’s XMLEncrypt™ service encrypts the sensitive strings stored in the localizable locations in Android.

Prerequisites for Using XMLEncrypt™:

To use Appdome’s mobile app security build system to Encrypt strings under strings.xml , you’ll need:

Encrypt strings under strings.xml on Android apps using Appdome

On Appdome, follow these 3 simple steps to create self-defending Android Apps that Encrypt strings under strings.xml 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. Android Formats: .apk or .aab
    4. XMLEncrypt™ Compatible With: Java, JS, C++, C#, Kotlin, Flutter, React Native, Unity, Xamarin, Cordova and other Android apps
  2. Build the feature: XMLEncrypt™.

    1. Building XMLEncrypt™ by using Appdome’s DEV-API:

      1. Create and name the Fusion Set (security template) that will contain the XMLEncrypt™ feature as shown below:
      2. fusion set that contains XMLEncrypt™

        Figure 1: Fusion Set that will contain the XMLEncrypt™ 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 XMLEncrypt™ feature via Appdome Console, to add the XMLEncrypt™ 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, as shown in Figure 1 above, and get 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 XMLEncrypt™ feature via Appdome Console

      To build the XMLEncrypt™ protection by using Appdome Console, follow the instructions below.

      1. Where: Inside the Appdome Console, go to Build > Security Tab > TOTALData™ Encryption section.
      2. When you select the XMLEncrypt™ you'll notice that your Fusion Set you created in step 2.1.1 now bears the icon of the protection category that contains XMLEncrypt™

        Fusion Set applied XMLEncrypt™

        Figure 4: Fusion Set that displays the newly added XMLEncrypt™ protection

      3. Extra Configuration with XMLEncrypt™:
        1. XMLEncrypt™

          Encrypt sensitive strings.xml values for all locales.

      4. Click Build My App at the bottom of the Build Workflow (shown in Figure 3).
    Congratulations!  The XMLEncrypt™ protection is now added to the mobile app

Using Threat-Events™ for strings under strings.xml Intelligence and Control in Android Apps

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

The specifications and options for Threat-Events™ for strings under strings.xml are:

Threat-Event™ Elements Encrypt strings under strings.xml Method Detail
Appdome Feature Name XMLEncrypt™
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 Encrypting strings under strings.xml 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
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

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 strings under strings.xml is detected.

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


Using Appdome, there are no development or coding prerequisites to build secured Android Apps by using XMLEncrypt™. 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 XMLEncrypt™

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:

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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