How to Encrypt Designated iOS Strings with In-App Secrets

Last updated March 6, 2024 by Appdome

Learn to Encrypt Strings and in App Secrets in iOS apps, in mobile CI/CD with a Data-Driven DevSecOps™ build system.

What is Strings and in-app Secrets encryption?

String and in app encryption is all the ways an app can statically encrypt/hide its sensitive strings from static analysis, while maintaining the same expected behavior when running the app on a device.

Most of the raw strings you define in your swift app code will be stored after compile in the result binary in certain sections. Those strings can be anything, error messages , hardcoded passwords or names, classes names, hints about data transferred to the server or hints about the flow of the program. generally speaking, when executing a program, your program will refer to those strings when needed in your code flow at the right time.

Raw strings of your app can be checked with simple tools, like MachoView or Otool, and view them in their sections.

Why encrypt Strings and in-app secrets?

Along with raw strings, all sensitive strings will be referred from your app code and those connections can be viewed by reversing tools like IDA/Ghidra, which gives the attacker knowledge about what conditions or circumstances will lead to the usage of a specific string and make the reversing of your app much easier and exposed.

Obfuscation is used against static reverse engineering attempts, one of the measures is encrypt the string/obfuscate them. This obfuscation should change the name of your sensitive in-app strings while maintaining the same expected behavior in the run time of your app.

Prerequisites for Using Encrypt Strings and in App Secrets:

To use Appdome’s mobile app security build system to Encrypt Strings and in App Secrets , you’ll need:

Appdome account (create a free Appdome account here)
A license for Encrypt Strings and in App Secrets
Mobile App (.ipa for iOS)
Signing Credentials (see Signing Secure Android apps and Signing Secure iOS apps)

Encrypt Strings and in App Secrets on iOS apps using Appdome

On Appdome, follow these 3 simple steps to create self-defending iOS Apps that Encrypt Strings and in App Secrets 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. iOS Formats: .ipa
4. Encrypt Strings and in App Secrets Compatible With: Obj-C, Java, Swift, Flutter, React Native, Unity, Xamarin, Cordova and more
Build the feature: Encrypt Strings and in App Secrets.
1. Building Encrypt Strings and in App Secrets by using Appdome’s DEV-API:
  1. Create and name the Fusion Set (security template) that will contain the Encrypt Strings and in App Secrets feature as shown below:
  2. Follow the steps in Sections 2.2.1-2.2.2 of this article, Building the Encrypt Strings and in App Secrets feature via Appdome Console, to add the Encrypt Strings and in App Secrets 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 Encrypt Strings and in App Secrets feature via Appdome Console
  
  To build the Encrypt Strings and in App Secrets 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™, Encrypt Strings and in App Secrets is turned on by default, as shown below:
    Figure 3: Encrypt Strings and in App Secrets 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 Encrypt Strings and in App Secrets you'll notice that your Fusion Set you created in step 2.1.1 now bears the icon of the protection category that contains Encrypt Strings and in App Secrets
    
    Figure 4: Fusion Set that displays the newly added Encrypt Strings and in App Secrets protection
  3. Optional Configuration with Encrypt Strings and in App Secrets:
    Advanced In-App Secrets Protection
    Encrypt application specific sensitive data such as keys, shared secrets and tokens.
  4. Click Build My App at the bottom of the Build Workflow (shown in Figure 3).
Congratulations! The Encrypt Strings and in App Secrets protection is now added to the mobile app
Certify the Encrypt Strings and in App Secrets feature in iOS Apps

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

Using Threat-Events™ for Strings and in App Secrets Intelligence and Control in iOS Apps

Appdome Threat-Events™ provides consumable in-app mobile app attack intelligence and defense control when Strings and in App Secrets is detected. To consume and use Threat-Events™ for Strings and in App Secrets in iOS Apps, use AddObserverForName in Notification Center, and the code samples for Threat-Events™ for Strings and in App Secrets shown below.

The specifications and options for Threat-Events™ for Strings and in App Secrets are:

Threat-Event™ Elements	Encrypt Strings and in App Secrets Method Detail
Appdome Feature Name	Encrypt Strings and in App Secrets
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 and in App Secrets 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.
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
updatedOSVersion	Is the OS version up to date
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), iOS developers can get detailed attack intelligence and granular defense control in iOS applications and create amazing user experiences for all mobile end users when Strings and in App Secrets is detected.

The following is a code sample for native iOS apps, which uses all values in the specification above for Encrypt Strings and in App Secrets:

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.

                    let center = NotificationCenter.default
                    center.addObserver(forName: Notification.Name(""), object: nil, queue: nil) { (note) in
                        guard let usrInf = note.userInfo else {
                            return
                        }

                        let message = usrInf["message"]; // Message shown to the user
                        let reasonData = usrInf["reasonData"]; // Threat detection cause
                        let reasonCode = usrInf["reasonCode"]; // Event reason code

                        // Current threat event score
                        let currentThreatEventScore = usrInf["currentThreatEventScore"];

                        // Total threat events score
                        let threatEventsScore = usrInf["threatEventsScore"];

                        // Replace '' with your specific event context key
                        // let variable = usrInf[""];

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

x
 
let center = NotificationCenter.default
center.addObserver(forName: Notification.Name(""), object: nil, queue: nil) { (note) in
    guard let usrInf = note.userInfo else {
        return
    }
​
    let message = usrInf["message"]; // Message shown to the user
    let reasonData = usrInf["reasonData"]; // Threat detection cause
    let reasonCode = usrInf["reasonCode"]; // Event reason code
​
    // Current threat event score
    let currentThreatEventScore = usrInf["currentThreatEventScore"];
​
    // Total threat events score
    let threatEventsScore = usrInf["threatEventsScore"];
​
    // Replace '<Context Key>' with your specific event context key
    // let variable = usrInf["<Context Key>"];
​
    // Your logic goes here (Send data to Splunk/Dynatrace/Show Popup...)
}

                    [[NSNotificationCenter defaultCenter] addObserverForName: @"" object:nil queue:nil usingBlock:^(NSNotification *org_note) {
                        __block NSNotification *note = org_note;
                        dispatch_async(dispatch_get_main_queue(), ^(void) {
                            // Message shown to the user
                            NSString *message = [[note userInfo] objectForKey:@"message"];
                            
                            // Threat detection cause
                            NSString *reasonData = [[note userInfo] objectForKey:@"reasonData"];
                            
                            // Event reason code
                            NSString *reasonCode = [[note userInfo] objectForKey:@"reasonCode"];

                            // Current threat event score
                            NSString *currentThreatEventScore = [[note userInfo] objectForKey:@"currentThreatEventScore"];
                            
                            // Total threat events score
                            NSString *threatEventsScore = [[note userInfo] objectForKey:@"threatEventsScore"];
                            
                            // Replace '' with your specific event context key
                            // NSString *variable = [[note userInfo] objectForKey:@""];

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

xxxxxxxxxx
 
[[NSNotificationCenter defaultCenter] addObserverForName: @"" object:nil queue:nil usingBlock:^(NSNotification *org_note) {
        __block NSNotification *note = org_note;
        dispatch_async(dispatch_get_main_queue(), ^(void) {
        
        // Message shown to the user
        NSString *message = [[note userInfo] objectForKey:@"message"];
      
        // Threat detection cause
        NSString *reasonData = [[note userInfo] objectForKey:@"reasonData"];
      
        // Event reason code
        NSString *reasonCode = [[note userInfo] objectForKey:@"reasonCode"];
​
        // Current threat event score
        NSString *currentThreatEventScore = [[note userInfo]        objectForKey:@"currentThreatEventScore"];
​
        // Total threat events score
        NSString *threatEventsScore = [[note userInfo] objectForKey:@"threatEventsScore"];
​
        // Replace '<Context Key>' with your specific event context key
        // NSString *variable = [[note userInfo] objectForKey:@"<Context Key>"];
​
        // Your logic goes here (Send data to Splunk/Dynatrace/Show Popup...)
    });
}];

                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 iOS Apps by using Encrypt Strings and in App Secrets. 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 Encrypt Strings and in App Secrets

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 Encrypt Designated iOS Strings with In-App Secrets

What is Strings and in-app Secrets encryption?

Why encrypt Strings and in-app secrets?

Prerequisites for Using Encrypt Strings and in App Secrets:

Encrypt Strings and in App Secrets on iOS apps using Appdome

Upload the Mobile App to Appdome.

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

Build the feature: Encrypt Strings and in App Secrets.

Building Encrypt Strings and in App Secrets by using Appdome’s DEV-API:

Building the Encrypt Strings and in App Secrets feature via Appdome Console

Certify the Encrypt Strings and in App Secrets feature in iOS Apps

Using Threat-Events™ for Strings and in App Secrets Intelligence and Control in iOS Apps

How Do I Learn More?

Thank you!

Supercharge the Experience in Mobile App Defense

Better User Experience in Mobile Defense

Shifting Dynamics in Mobile Fraud Prevention: A Call for Developer Responsibility

Eliminating Information Asymmetry in the Attack Chain With GenAI