How to Apply Data-at-Rest Encryption to Downloads Performed via Android's DownloadManager API

Last updated August 28, 2023 by Appdome

Learn to Enforce the execution of the app’s downloads within the app’s context in Android apps, in mobile CI/CD with a Data-Driven DevSecOps™ build system.

Why Data-at-Rest Encryption is Essential for Android's DownloadManager API Downloads?

Data-at-Rest Encryption is pivotal for downloads managed by Android’s DownloadManager API. The primary reason is that these files, once downloaded, reside directly on the device’s storage, making them susceptible to various security threats if the device is compromised. While Android’s DownloadManager facilitates the seamless download of files, it doesn’t inherently offer the same granular security controls that an app might provide for other data it handles. This distinction means that developers may struggle to apply the same protective measures to these downloaded files as they do to the rest of their application. To ensure the integrity and safety of the data, robust security measures are essential. Without them, these files could be vulnerable to potential threats from malicious apps or unauthorized users.

Appdome’s Secure Download ensures that files downloaded by the app are not sent to the Android Download Manager and are executed within the app’s context. In doing so, data encryption is applied to all downloaded files.

How Appdome Secure Download Works?

Appdome Secure Download operates by “catching” the download request within an Appdome Built app, executing it directly within the app’s secure environment. This functionality ensures the application of Data at Rest Encryption to files before they are securely stored on the device. When Secure Download is enabled, the app identifies the device’s Download Manager API call to guarantee secure file downloads. This process also ensures that files aren’t directed to the standard Android Download Manager but remain within the app’s context, receiving the added protection of data encryption.

Note:
Secure Download protects all downloads made by the standard Android Download Manager used in the app. As part of Android Download’s Manager operation, a notification is sent showing the download progress and stating that a file has been downloaded. Due to changes in Notification runtime permission starting from Android 13, the download notification will only appear after the application has requested and the user has granted notification permission.
For more information, please visit: https://developer.android.com/develop/ui/views/notifications/channels

Prerequisites for Using Data at Rest Encryption > Secure Download:

To use Appdome’s mobile app security build system to Enforce the execution of the app’s downloads within the app’s context , you’ll need:

Appdome account (create a free Appdome account here)
A license for Data at Rest Encryption > Secure Download
Mobile App (.apk or .aab for Android)
Signing Credentials (see Signing Secure Android apps and Signing Secure iOS apps)

Enforce the execution of the app’s downloads within the app’s context on Android apps using Appdome

On Appdome, follow these 3 simple steps to create self-defending Android Apps that Enforce the execution of the app’s downloads within the app’s context without an SDK or gateway:

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. Data at Rest Encryption > Secure Download Compatible With: Java, JS, C++, C#, Kotlin, Flutter, React Native, Unity, Xamarin, Cordova and other Android apps
Build the feature: Data at Rest Encryption > Secure Download.
1. Building Data at Rest Encryption > Secure Download by using Appdome’s DEV-API:
  1. Create and name the Fusion Set (security template) that will contain the Data at Rest Encryption > Secure Download feature as shown below:
  2. Follow the steps in Sections 2.2.1-2.2.2 of this article, Building the Data at Rest Encryption > Secure Download feature via Appdome Console, to add the Data at Rest Encryption > Secure Download feature to this Fusion Set.
  3. 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):”
    
    Figure 2: Fusion Set Detail Summary
    Note: Annotating the Fusion Set to identify the protection(s) selected is optional only (not mandatory).
  4. 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:
    
    Build an API for the app – for instructions, see the tasks under Appdome API Reference Guide
    
    Look for sample APIs in Appdome’s GitHub Repository
2. Building the Data at Rest Encryption > Secure Download feature via Appdome Console
  
  To build the Data at Rest Encryption > Secure Download protection by using Appdome Console, follow the instructions below.
  1. Where: Inside the Appdome Console, go to Build > Security Tab > TOTALData™ Encryption section.
    Like all other options in ONEShield™, Data at Rest Encryption > Secure Download is turned on by default, as shown below:
    Figure 3: Data at Rest Encryption > Secure Download option
    Note: The App Compromise Notification contains an easy to follow default remediation path for the mobile app end user. You can customize this message as required to achieve brand specific support, workflow or other messaging.
  2. How: Toggle (turn ON) Data at Rest Encryption > Secure Download, as shown below.
    
    Figure 3: Enforce the execution of the app’s downloads within the app’s context option
  3. When you select the Data at Rest Encryption > Secure Download you'll notice that your Fusion Set you created in step 2.1.1 now bears the icon of the protection category that contains Data at Rest Encryption > Secure Download
    
    Figure 4: Fusion Set that displays the newly added Data at Rest Encryption > Secure Download protection
  4. Click Build My App at the bottom of the Build Workflow (shown in Figure 3).
Congratulations! The Data at Rest Encryption > Secure Download protection is now added to the mobile app
Certify the Data at Rest Encryption > Secure Download feature in Android Apps.

After building Data at Rest Encryption > Secure Download, Appdome generates a Certified Secure™ certificate to guarantee that the Data at Rest Encryption > Secure Download protection has been added and is protecting the app. To verify that the Data at Rest Encryption > Secure Download protection has been added to the mobile app, locate the protection in the Certified Secure™ certificate as shown below:

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 Data at Rest Encryption > Secure Download has been added to each Android app. Certified Secure provides instant and in-line DevSecOps compliance certification that Data at Rest Encryption > Secure Download and other mobile app security features are in each build of the mobile app

Using Threat-Events™ for the execution of the app’s downloads within the app’s context Intelligence and Control in Android Apps

Appdome Threat-Events™ provides consumable in-app mobile app attack intelligence and defense control when the execution of the app’s downloads within the app’s context is detected. To consume and use Threat-Events™ for the execution of the app’s downloads within the app’s context in Android Apps, use registerReceiver in the Application OnCreate, and the code samples for Threat-Events™ for the execution of the app’s downloads within the app’s context shown below.

The specifications and options for Threat-Events™ for the execution of the app’s downloads within the app’s context are:

Threat-Event™ Elements	Enforce the execution of the app’s downloads within the app’s context Method Detail
Appdome Feature Name	Data at Rest Encryption > Secure Download
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 Enforcing the execution of the app’s downloads within the app’s context 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 the execution of the app’s downloads within the app’s context is detected.

The following is a code sample for native Android apps, which uses all values in the specification above for Data at Rest Encryption > Secure Download:

                    IntentFilter intentFilter = new IntentFilter();
                    intentFilter.addAction("");
                    BroadcastReceiver threatEventReceiver = new BroadcastReceiver() {
                        @Override
                        public void onReceive(Context context, Intent intent) {
                            String message = intent.getStringExtra("message"); // Message shown to the user
                            String reasonData = intent.getStringExtra("reasonData"); // Threat detection cause
                            String reasonCode = intent.getStringExtra("reasonCode"); // Event reason code
                            String currentThreatEventScore = intent.getStringExtra("currentThreatEventScore"); // Current threat event score
                            String threatEventsScore = intent.getStringExtra("threatEventsScore"); // Total threat events score
                            String variable = intent.getStringExtra(""); // Any other event specific context key

                            // Your logic goes here (Send data to Splunk/Dynatrace/Show Popup...)
                        }
                    };

                    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.TIRAMISU) {
                        registerReceiver(threatEventReceiver, intentFilter, Context.RECEIVER_NOT_EXPORTED);
                    } else {
                        registerReceiver(threatEventReceiver, intentFilter);
                    }

Java
x
 
IntentFilter intentFilter = new IntentFilter();
intentFilter.addAction("");
BroadcastReceiver threatEventReceiver = new BroadcastReceiver() {
    @Override
    public void onReceive(Context context, Intent intent) {
        String message = intent.getStringExtra("message"); // Message shown to the user
        String reasonData = intent.getStringExtra("reasonData"); // Threat detection cause
        String reasonCode = intent.getStringExtra("reasonCode"); // Event reason code
        String currentThreatEventScore = intent.getStringExtra("currentThreatEventScore"); // Current threat event score
        String threatEventsScore = intent.getStringExtra("threatEventsScore"); // Total threat events score
        String variable = intent.getStringExtra("<Context Key>"); // Any other event specific context key
​
        // Your logic goes here (Send data to Splunk/Dynatrace/Show Popup...)
    }
};
​
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.TIRAMISU) {
    registerReceiver(threatEventReceiver, intentFilter, Context.RECEIVER_NOT_EXPORTED);
} else {
    registerReceiver(threatEventReceiver, intentFilter);
}

                    val intentFilter = IntentFilter()
                    intentFilter.addAction("")
                    val threatEventReceiver = object : BroadcastReceiver() {
                        override fun onReceive(context: Context?, intent: Intent?) {
                            var message = intent?.getStringExtra("message") // Message shown to the user
                            var reasonData = intent?.getStringExtra("reasonData") // Threat detection cause
                            var reasonCode = intent?.getStringExtra("reasonCode") // Event reason code
                            var currentThreatEventScore = intent?.getStringExtra("currentThreatEventScore") // Current threat event score
                            var threatEventsScore = intent?.getStringExtra("threatEventsScore") // Total threat events score
                            var variable = intent?.getStringExtra("") // Any other event specific context key

                            // Your logic goes here (Send data to Splunk/Dynatrace/Show Popup...)
                        }
                    }

                    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.TIRAMISU) {
                        registerReceiver(threatEventReceiver, intentFilter, Context.RECEIVER_NOT_EXPORTED)
                    } else {
                        registerReceiver(threatEventReceiver, intentFilter)
                    }

                         
                        Kotlin
                    
x
 
val intentFilter = IntentFilter()
intentFilter.addAction("")
val threatEventReceiver = object : BroadcastReceiver() {
    override fun onReceive(context: Context?, intent: Intent?) {
        var message = intent?.getStringExtra("message") // Message shown to the user
        var reasonData = intent?.getStringExtra("reasonData") // Threat detection cause
        var reasonCode = intent?.getStringExtra("reasonCode") // Event reason code
        var currentThreatEventScore = intent?.getStringExtra("currentThreatEventScore") // Current threat event score
        var threatEventsScore = intent?.getStringExtra("threatEventsScore") // Total threat events score
        var variable = intent?.getStringExtra("<Context Key>") // Any other event specific context key
​
        // Your logic goes here (Send data to Splunk/Dynatrace/Show Popup...)
    }
}
​
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.TIRAMISU) {
    registerReceiver(threatEventReceiver, intentFilter, Context.RECEIVER_NOT_EXPORTED)
} else {
    registerReceiver(threatEventReceiver, intentFilter)
}

const { ADDevEvents } = NativeModules;
                const aDDevEvents = new NativeEventEmitter(ADDevEvents);

                function registerToDevEvent(action, callback) {
                    NativeModules.ADDevEvents.registerForDevEvent(action);
                    aDDevEvents.addListener(action, callback);
                }

                export function registerToAllEvents() {
                    registerToDevEvent(
                        "",
                        (userinfo) => Alert.alert(JSON.stringify(userinfo))

                        var message = userinfo["message"] // Message shown to the user
                        var reasonData = userinfo["reasonData"] // Threat detection cause
                        var reasonCode = userinfo["reasonCode"] // Event reason code
                        var currentThreatEventScore = userinfo["currentThreatEventScore"] // Current threat event score
                        var threatEventsScore = userinfo["threatEventsScore"] // Total threat events score
                        var variable = userinfo["<Context Key>"] // Any other event specific context key

                        // Your logic goes here (Send data to Splunk/Dynatrace/Show Popup...)
                    );
                }

                     
                    React Native
                
​x
 
const { ADDevEvents } = NativeModules;
const aDDevEvents = new NativeEventEmitter(ADDevEvents);
​
function registerToDevEvent(action, callback) {
    NativeModules.ADDevEvents.registerForDevEvent(action);
    aDDevEvents.addListener(action, callback);
}
​
export function registerToAllEvents() {
    registerToDevEvent(
        "",
        (userinfo) => Alert.alert(JSON.stringify(userinfo))
​
        var message = userinfo["message"] // Message shown to the user
        var reasonData = userinfo["reasonData"] // Threat detection cause
        var reasonCode = userinfo["reasonCode"] // Event reason code
        var currentThreatEventScore = userinfo["currentThreatEventScore"] // Current threat event score
        var threatEventsScore = userinfo["threatEventsScore"] // Total threat events score
        var variable = userinfo["<Context Key>"] // Any other event specific context key
​
        // Your logic goes here (Send data to Splunk/Dynatrace/Show Popup...)
    );
}
​

RegisterReceiver(new ThreatEventReceiver(), new IntentFilter(""));
                class ThreatEventReceiver : BroadcastReceiver
                {
                public override void OnReceive(Context context, Intent intent)
                {
                    String message = intent.GetStringExtra("message"); // Message shown to the user
                    String reasonData = intent.GetStringExtra("reasonData"); // Threat detection cause
                    String reasonCode = intent.GetStringExtra("reasonCode"); // Event reason code
                    String currentThreatEventScore = intent.GetStringExtra("currentThreatEventScore"); // Current threat event score
                    String threatEventsScore = intent.GetStringExtra("threatEventsScore"); // Total threat events score
                    String variable = intent.GetStringExtra("<Context Key>"); // Any other event specific context key

                    // Your logic goes here (Send data to Splunk/Dynatrace/Show Popup...)
                }
                }

                    
                    Xamarin/MAUI Android
                
​x
 
RegisterReceiver(new ThreatEventReceiver(), new IntentFilter(""));
​
class ThreatEventReceiver : BroadcastReceiver
{
  public override void OnReceive(Context context, Intent intent)
  {
    String message = intent.GetStringExtra("message"); // Message shown to the user
    String reasonData = intent.GetStringExtra("reasonData"); // Threat detection cause
    String reasonCode = intent.GetStringExtra("reasonCode"); // Event reason code
    String currentThreatEventScore = intent.GetStringExtra("currentThreatEventScore"); // Current threat event score
    String threatEventsScore = intent.GetStringExtra("threatEventsScore"); // Total threat events score
    String variable = intent.GetStringExtra("<Context Key>"); // Any other event specific context key
​
    // Your logic goes here (Send data to Splunk/Dynatrace/Show Popup...)
  }
}

                NSNotificationCenter.DefaultCenter.AddObserver(
                    (NSString)"JailbrokenDevice", // Threat-Event Identifier
                    delegate (NSNotification notification)
                    {
                        var message = notification.UserInfo.ObjectForKey("message"); // Message shown to the user
                        var reasonData = notification.UserInfo.ObjectForKey("reasonData"); // Threat detection cause
                        var reasonCode = notification.UserInfo.ObjectForKey("reasonCode"); // Event reason code
                        var currentThreatEventScore = notification.UserInfo.ObjectForKey("currentThreatEventScore"); // Current threat event score
                        var threatEventsScore = notification.UserInfo.ObjectForKey("threatEventsScore"); // Total threat events score
                        var variable = notification.UserInfo.ObjectForKey(""); // Any other event specific context key
                        // Your logic goes here (Send data to Splunk/Dynatrace/Show Popup...)
                    });

                    
                    Xamarin/MAUI iOS
                
 
NSNotificationCenter.DefaultCenter.AddObserver(
  (NSString)"", // Threat-Event Identifier
  delegate (NSNotification notification)
  {
    var message = notification.UserInfo.ObjectForKey("message"); // Message shown to the user
    var reasonData = notification.UserInfo.ObjectForKey("reasonData"); // Threat detection cause
    var reasonCode = notification.UserInfo.ObjectForKey("reasonCode"); // Event reason code
    var currentThreatEventScore = notification.UserInfo.ObjectForKey("currentThreatEventScore"); // Current threat event score
    var threatEventsScore = notification.UserInfo.ObjectForKey("threatEventsScore"); // Total threat events score
    var variable = notification.UserInfo.ObjectForKey("<Context Keys>"); // Any other event specific context key
    // Your logic goes here (Send data to Splunk/Dynatrace/Show Popup...)
  });

window.broadcaster.addEventListener("", function(userInfo) {
        var message = userInfo.message // Message shown to the user
        var reasonData = userInfo.reasonData // Threat detection cause
        var reasonCode = userInfo.reasonCode // Event reason code
        var currentThreatEventScore = userInfo.currentThreatEventScore // Current threat event score
        var threatEventsScore = userInfo.threatEventsScore // Total threat events score
        var variable = userInfo.<Context Key> // Any other event specific context key

        // Your logic goes here (Send data to Splunk/Dynatrace/Show Popup...)
            });

                    
                    Cordova
                
​x
 
window.broadcaster.addEventListener("", function(userInfo) {
        var message = userInfo.message // Message shown to the user
        var reasonData = userInfo.reasonData // Threat detection cause
        var reasonCode = userInfo.reasonCode // Event reason code
        var currentThreatEventScore = userInfo.currentThreatEventScore // Current threat event score
        var threatEventsScore = userInfo.threatEventsScore // Total threat events score
        var variable = userInfo.<Context Key> // Any other event specific context key
​
        // Your logic goes here (Send data to Splunk/Dynatrace/Show Popup...)
});

                import 'dart:async';
                import 'package:flutter/material.dart';
                import 'package:flutter/services.dart';

                class PlatformChannel extends StatefulWidget {
                  const PlatformChannel({super.key});

                  @override
                  State<PlatformChannel> createState() => _PlatformChannelState();
                }

                class _PlatformChannelState extends State<PlatformChannel> {
                  static const String _eventChannelName = ""; // Replace with your EventChannel name
                  static const EventChannel _eventChannel = EventChannel(_eventChannelName);

                  @override
                  void initState() {
                    super.initState();
                    _eventChannel.receiveBroadcastStream().listen(_onEvent, onError: _onError);
                  }

                  void _onEvent(Object? event) {
                    setState(() {
                      // Adapt this section based on your specific event data structure
                      var eventData = event as Map;

                      // Example: Accessing 'externalID' field from the event
                      var externalID = eventData['externalID'];

                      // Customize the rest of the fields based on your event structure
                      String message = eventData['message']; // Message shown to the user
                      String reasonData = eventData['reasonData']; // Threat detection cause
                      String reasonCode = eventData['reasonCode']; // Event reason code
                      String currentThreatEventScore = eventData['currentThreatEventScore']; // Current threat event score
                      String threatEventsScore = eventData['threatEventsScore']; // Total threat events score

                      // Any other event specific context key
                      String variable = eventData['<Context Key>'];
                    });
                  }

                  // Your logic goes here (Send data to Splunk/Dynatrace/Show Popup...)
                }

                    
                    Flutter
                
xxxxxxxxxx
 
import 'dart:async';
​
import 'package:flutter/material.dart';
import 'package:flutter/services.dart';
​
class PlatformChannel extends StatefulWidget {
  const PlatformChannel({super.key});
​
  @override
  State<PlatformChannel> createState() => _PlatformChannelState();
}
​
class _PlatformChannelState extends State<PlatformChannel> {
  static const String _eventChannelName = ''; // Replace with your EventChannel name
  static const EventChannel _eventChannel = EventChannel(_eventChannelName);
​
  @override
  void initState() {
    super.initState();
    _eventChannel.receiveBroadcastStream().listen(_onEvent, onError: _onError);
  }
​
  void _onEvent(Object? event) {
    setState(() {
      // Adapt this section based on your specific event data structure
      var eventData = event as Map;
​
      // Example: Accessing 'externalID' field from the event
      var externalID = eventData['externalID'];
​
      // Customize the rest of the fields based on your event structure
      String message = eventData['message']; // Message shown to the user
      String reasonData = eventData['reasonData']; // Threat detection cause
      String reasonCode = eventData['reasonCode']; // Event reason code
      String currentThreatEventScore = eventData['currentThreatEventScore']; // Current threat event score
      String threatEventsScore = eventData['threatEventsScore']; // Total threat events score
​
      // Any other event specific context key
      String variable = eventData['<Context Key>'];
    });
  }
​
  // Your logic goes here (Send data to Splunk/Dynatrace/Show Popup...)
}

Using Appdome, there are no development or coding prerequisites to build secured Android Apps by using Data at Rest Encryption > Secure Download. 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 Data at Rest Encryption > Secure Download

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:

Customizing, Configuring & Branding Secure Mobile Apps
Deploying/Publishing Secure mobile apps to Public or Private app stores
Releasing Secured Android & iOS Apps built on Appdome.

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.

How to Apply Data-at-Rest Encryption to Downloads Performed via Android's DownloadManager API

Why Data-at-Rest Encryption is Essential for Android's DownloadManager API Downloads?

How Appdome Secure Download Works?

Prerequisites for Using Data at Rest Encryption > Secure Download:

Enforce the execution of the app’s downloads within the app’s context on Android apps using Appdome

Upload the Mobile App to Appdome.

Upload an app to Appdome’s Mobile App Security Build System

Build the feature: Data at Rest Encryption > Secure Download.

Building Data at Rest Encryption > Secure Download by using Appdome’s DEV-API:

Building the Data at Rest Encryption > Secure Download feature via Appdome Console

Certify the Data at Rest Encryption > Secure Download feature in Android Apps.

Using Threat-Events™ for the execution of the app’s downloads within the app’s context Intelligence and Control in Android Apps

Related Articles:

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