How to Enable Secure Offline Access for Android apps

Last updated November 23, 2023 by Appdome

Learn to Add offline access in Android apps, in mobile CI/CD with a Data-Driven DevSecOps™ build system.

What is offline access?

Mobile TOTALData Encryption is used for protecting data stored within a mobile app. Smart Offline Handling is an extension to Appdome TOTALData Encryption, which allows developers of apps that require authentication to enable access to some of the files that the app generates.
With Appdome TOTALData^TM Encryption, all data stored inside the mobile app (including media files) is encrypted at run-time by using industry-standard AES-256 cryptographic protocols. When the Appdome Smart Offline Handoff option is enabled, Appdome decrypts the app’s data only after the user successfully authenticates.
Additionally, the developer can specify a folder for offline file access, along with the required conditions that must be met in order to permit offline access to the data (for example the required conditions may include a time expiration, or require additional authentication, such as a pincode or biometric authentication). To enable this feature you need to toggle on the Require Local Authentication feature.
Another way to enhance the security in this feature, is to enable Store in Protected Memory toggle. This enables storing the encryption key used for the offline folder in an encrypted memory segment, thereby preventing attackers from seeing the key when dumping the application’s memory.

Why Use Smart Offline Handoff?

Security-conscious developers may sometimes want to restrict access to offline data or to introduce additional security requirements on users in order to grant offline access.; for example, to only allow offline access after successful authentication with a remote server. They may also want to limit offline access to the data to a certain time-frame or require additional authentication. With Appdome’s Smart Offline Handoff the developers may achieve those goals and harden the security on certain files generated by the application, such as sensitive user information, while allowing them safe access at the same time.

Prerequisites for Using Smart Offline Handoff:

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

Appdome account (create a free Appdome account here)
A license for Smart Offline Handoff
Mobile App (.apk or .aab for Android)
Signing Credentials (see Signing Secure Android apps and Signing Secure iOS apps)

Add offline access on Android apps using Appdome

On Appdome, follow these 3 simple steps to create self-defending Android Apps that Add offline access 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. Smart Offline Handoff Compatible With: Java, JS, C++, C#, Kotlin, Flutter, React Native, Unity, Xamarin, Cordova and other Android apps
Build the feature: Smart Offline Handoff.
1. Building Smart Offline Handoff by using Appdome’s DEV-API:
  1. Create and name the Fusion Set (security template) that will contain the Smart Offline Handoff feature as shown below:
  2. Follow the steps in Sections 2.2.1-2.2.2 of this article, Building the Smart Offline Handoff feature via Appdome Console, to add the Smart Offline Handoff 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 Smart Offline Handoff feature via Appdome Console
  
  To build the Smart Offline Handoff 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™, Smart Offline Handoff is turned on by default, as shown below:
    Figure 3: Smart Offline Handoff 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. When you select the Smart Offline Handoff you'll notice that your Fusion Set you created in step 2.1.1 now bears the icon of the protection category that contains Smart Offline Handoff
    
    Figure 4: Fusion Set that displays the newly added Smart Offline Handoff protection
  3. Click Build My App at the bottom of the Build Workflow (shown in Figure 3).
Congratulations! The Smart Offline Handoff protection is now added to the mobile app
Certify the Smart Offline Handoff feature in Android Apps

After building Smart Offline Handoff, Appdome generates a Certified Secure™ certificate to guarantee that the Smart Offline Handoff protection has been added and is protecting the app. To verify that the Smart Offline Handoff 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 Smart Offline Handoff has been added to each Android app. Certified Secure provides instant and in-line DevSecOps compliance certification that Smart Offline Handoff and other mobile app security features are in each build of the mobile app

Using Threat-Events™ for offline access Intelligence and Control in Android Apps

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

The specifications and options for Threat-Events™ for offline access are:

Threat-Event™ Elements	Add offline access Method Detail
Appdome Feature Name	Smart Offline Handoff
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 Adding offline access 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

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 offline access is detected.

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

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.

                    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
                            
                            // Current threat event score
                            String currentThreatEventScore = intent.getStringExtra("currentThreatEventScore");
                            
                            // Total threat events score
                            String threatEventsScore = intent.getStringExtra("threatEventsScore");
                            
                            // Replace '' with your specific event context key
                            // String variable = intent.getStringExtra("");

                            // 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);
                    }

xxxxxxxxxx
 
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
​
    // Current threat event score
    String currentThreatEventScore = intent.getStringExtra("currentThreatEventScore");
​
    // Total threat events score
    String threatEventsScore = intent.getStringExtra("threatEventsScore");
​
    // Replace '<Context Key>' with your specific event context key
    // String variable = intent.getStringExtra("<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
                            
                            // Current threat event score
                            var currentThreatEventScore = intent?.getStringExtra("currentThreatEventScore")
                            
                            // Total threat events score
                            var threatEventsScore = intent?.getStringExtra("threatEventsScore")
                            
                            // Replace '' with your specific event context key
                            // var variable = intent?.getStringExtra("")

                            // 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)
                    }

xxxxxxxxxx
 
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
          
        // Current threat event score
        var currentThreatEventScore = intent?.getStringExtra("currentThreatEventScore")
          
        // Total threat events score
        var threatEventsScore = intent?.getStringExtra("threatEventsScore")
          
        // Replace '<Context Key>' with your specific event context key
        // var variable = intent?.getStringExtra("<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

                        // Current threat event score
                        var currentThreatEventScore = userinfo["currentThreatEventScore"]

                        // Total threat events score
                        var threatEventsScore = userinfo["threatEventsScore"]

                        // Replace '' with your specific event context key
                        // var variable = userinfo[""]

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

xxxxxxxxxx
 
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
​
        // Current threat event score
        var currentThreatEventScore = userinfo["currentThreatEventScore"]
​
        // Total threat events score
        var threatEventsScore = userinfo["threatEventsScore"]
​
        // Replace '<Context Key>' with your specific event context key
        // var variable = userinfo["<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

                        // Current threat event score
                        String currentThreatEventScore = intent.GetStringExtra("currentThreatEventScore");

                        // Total threat events score
                        String threatEventsScore = intent.GetStringExtra("threatEventsScore");

                        // Replace '' with your specific event context key
                        // String variable = intent.GetStringExtra("");

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

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

                NSNotificationCenter.DefaultCenter.AddObserver(
                    (NSString)"", // Threat-Event Identifier
                    delegate (NSNotification notification)
                    {
                        // Message shown to the user
                        var message = notification.UserInfo.ObjectForKey("message");
                        
                        // Threat detection cause
                        var reasonData = notification.UserInfo.ObjectForKey("reasonData");
                        
                        // Event reason code
                        var reasonCode = notification.UserInfo.ObjectForKey("reasonCode");

                        // Current threat event score
                        var currentThreatEventScore = notification.UserInfo.ObjectForKey("currentThreatEventScore");
                        
                        // Total threat events score
                        var threatEventsScore = notification.UserInfo.ObjectForKey("threatEventsScore");

                        // Replace '' with your specific event context key
                        // var variable = notification.UserInfo.ObjectForKey("");

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

x
 
NSNotificationCenter.DefaultCenter.AddObserver(
    (NSString)"", // Threat-Event Identifier
    delegate (NSNotification notification)
    {
        // Message shown to the user
        var message = notification.UserInfo.ObjectForKey("message");
​
        // Threat detection cause
        var reasonData = notification.UserInfo.ObjectForKey("reasonData");
​
        // Event reason code
        var reasonCode = notification.UserInfo.ObjectForKey("reasonCode");
​
        // Current threat event score
        var currentThreatEventScore = notification.UserInfo.ObjectForKey("currentThreatEventScore");
​
        // Total threat events score
        var threatEventsScore = notification.UserInfo.ObjectForKey("threatEventsScore");
​
        // Replace '<Context Key>' with your specific event context key
        // var variable = notification.UserInfo.ObjectForKey("<Context Keys>");
​
        // 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

                    // Current threat event score
                    var currentThreatEventScore = userInfo.currentThreatEventScore

                    // Total threat events score
                    var threatEventsScore = userInfo.threatEventsScore

                    // Replace '' with your specific event context key
                    // var variable = userInfo.

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

xxxxxxxxxx
 
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
​
    // Current threat event score
    var currentThreatEventScore = userInfo.currentThreatEventScore
​
    // Total threat events score
    var threatEventsScore = userInfo.threatEventsScore
​
    // Replace '<Context Key>' with your specific event context key
    // var variable = userInfo.<Context Keys>
​
    // 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 createState() => _PlatformChannelState();
                }

                class _PlatformChannelState extends State {
                    // Replace with your EventChannel name
                    static const String _eventChannelName = "";
                    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

                            // Current threat event score
                            String currentThreatEventScore = eventData['currentThreatEventScore'];

                            // Total threat events score
                            String threatEventsScore = eventData['threatEventsScore'];

                            // Replace '' with your specific event context key
                            // String variable = eventData[''];
                        });
                    }

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

x
 
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> {
    // Replace with your EventChannel name
    static const String _eventChannelName = "";
    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
​
            // Current threat event score
            String currentThreatEventScore = eventData['currentThreatEventScore'];
​
            // Total threat events score
            String threatEventsScore = eventData['threatEventsScore'];
​
            // Replace '<Context Key>' with your specific event context key
            // String variable = eventData['<Context Keys>'];
        });
    }
​
    // 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 Smart Offline Handoff. 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 Smart Offline Handoff

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.

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.

How to Enable Secure Offline Access for Android apps

What is offline access?

Why Use Smart Offline Handoff?

Prerequisites for Using Smart Offline Handoff:

Add offline access 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: Smart Offline Handoff.

Building Smart Offline Handoff by using Appdome’s DEV-API:

Building the Smart Offline Handoff feature via Appdome Console

Certify the Smart Offline Handoff feature in Android Apps

Using Threat-Events™ for offline access Intelligence and Control in Android Apps

Related Articles:

How Do I Learn More?

Thank you!

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