How to Enforce SHA-256 Digest in Android & iOS Apps
This Knowledge Base article describes how to use Appdome’s AI/ML in your CI/CD pipeline to continuously deliver plugins that Enforce SHA-256 Digest in Mobile apps.
What is a SHA-256 Digest?
A SHA-256 Digest is a type of cryptographic hash function that belongs to the SHA-2 family. It is used to generate a distinct 32-byte (256-bit) signature for data blocks, which helps to ensure high levels of security and authenticity. When it comes to certificate hardening, the SHA-256 digest makes a unique fingerprint of each certificate’s data within a chain. This includes the leaf certificate that protects client-server interactions and the CA root certificates that ensure the chain is trustworthy. The leaf certificate directly secures communications between the client (mobile app) and the server, while the CA (Certificate Authority) root certificate validates the authenticity and trustworthiness of the entire certificate chain. Each certificate serves a different but equally important role in maintaining the security and integrity of digital communications.
Why Enforce SHA-256 Digest in Mobile Apps?
The security community has shifted from SHA-1 to SHA-256 due to vulnerabilities in SHA-1, which by 2017 led to its discontinuation by major browsers and technology firms, marking it as weak and insecure for cryptographic uses. Most security professionals and reputed security organizations now recommend SHA-2, which is significantly stronger. Implementing SHA-256 in mobile apps helps protect against various security threats, such as data tampering and collision attacks. By enforcing the use of SHA-256, developers ensure that sensitive information, including user credentials, financial transactions, and other critical data, is safeguarded against unauthorized modifications. This robust hashing algorithm also supports secure digital signatures, which are vital for verifying the integrity and origin of data transmitted between the mobile app and the server.
In addition to enforcing the SHA-256 digest, you can enhance your mobile app’s security by using Appdome’s features, such as Secure Certificate Pinning, Enforce Certificate Roles, Enforce Strong RSA Signature, and Enforce Strong ECC Signature. These features work in conjunction to provide a comprehensive security framework, ensuring the highest level of protection for your mobile applications.
Prerequisites for Using Appdome's Enforce SHA-256 Digest Plugins:
To use Appdome’s mobile app security build system to Enforce SHA-256 Digest , you’ll need:
- Appdome account (create a free Appdome account here)
- A license for Enforce SHA-256 Digest
- Mobile App (.ipa for iOS, or .apk or .aab for Android)
- Signing Credentials (see Signing Secure Android apps and Signing Secure iOS apps)
How to Implement Enforce SHA-256 Digest in Mobile Apps Using Appdome
On Appdome, follow these 3 simple steps to create self-defending Mobile Apps that Enforce SHA-256 Digest without an SDK or gateway:
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Designate the Mobile App to be protected.
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Upload an app via the Appdome Mobile Defense platform GUI or via Appdome’s DEV-API or CI/CD Plugins.
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Mobile App Formats: .ipa for iOS, or .apk or .aab for Android
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Enforce SHA-256 Digest is compatible with: Obj-C, Java, JS, C#, C++, Swift, Kotlin, Flutter, React Native, Unity, Xamarin, and more.
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Select the defense: Enforce SHA-256 Digest .
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Follow the steps in Sections 2.2-2.2.2 of this article to add the Enforce SHA-256 Digest feature to your Fusion Set via the Appdome Console.
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When you select the Enforce SHA-256 Digest you'll notice that the Fusion Set you created in step 2.1 now bears the icon of the protection category that contains Enforce SHA-256 Digest .
Figure 2: Fusion Set that displays the newly added Enforce SHA-256 Digest protection
Note: Annotating the Fusion Set to identify the protection(s) selected is optional only (not mandatory). -
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 3: Fusion Set Detail Summary
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Follow the instructions below to use the Fusion Set ID inside any standard mobile DevOps or CI/CD toolkit like Bitrise, Jenkins, Travis, Team City, Circle CI or other system:
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Refer to the Appdome API Reference Guide for API building instructions.
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Look for sample APIs in Appdome’s GitHub Repository.
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Create and name the Fusion Set (security template) that will contain the Enforce SHA-256 Digest feature as shown below:
Figure 1: Fusion Set that will contain the Enforce SHA-256 Digest feature
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Add the Enforce SHA-256 Digest feature to your security template.
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Navigate to Build > Security tab > Secure Communication section in the Appdome Console.
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Toggle On > Enforce SHA-256 Digest .
(a) Choose to monitor this attack vector by checking the Threat Events checkbox associated with Enforce SHA-256 Digest as shown below.
(b) To receive mobile Threat Monitoring, check the ThreatScope™ box as shown below. For more details, see our knowledge base article on ThreatScope™ Mobile XDR.
Figure 4: Selecting Enforce SHA-256 Digest
Note: The Appdome Platform displays the Mobile Operation Systems supported by each defense in real-time. For more details, see our OS Support Policy KB. -
Select the Threat-Event™ in-app mobile Threat Defense and Intelligence policy for Enforce SHA-256 Digest :
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Threat-Events™ OFF > In-App Defense
If the Threat-Events™ setting is not selected. Appdome will detect and defend the user and app by enforcing SHA-256 Digest .
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Threat-Events™ ON > In-App Detection
When this setting is used, Appdome detects the use of a weak certificate signature and passes Appdome’s Threat-Event™ attack intelligence to the app’s business logic for processing, enforcement, and user notification. For more information on consuming and using Appdome Threat-Events™ in the app, see section Using Threat-Events™ to Enforce SHA-256 Digest Enforce Intelligence and Control in Mobile Apps.
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Threat-Events™ ON > In-App Defense
When this setting is used, Appdome detects and defends against SHA-256 Digest (same as Appdome Enforce) and passes Appdome’s Threat-Event™ attack intelligence to the app’s business logic for processing. For more information on consuming and using Appdome Threat-Events™ in the app, see section Using Threat-Events™ for Enforce SHA-256 Digest Enforce Intelligence and Control in Mobile Apps.
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Configure the User Experience Options for Enforce SHA-256 Digest :
With Threat-Events™ OFF, Appdome provides several user experience options for mobile brands and developers.- App Compromise Notification: Customize the pop-up or toast Appdome uses to notify the user when a threat is present while using the protected mobile app.
- Short message Option. This is available for mobile devices that allow a banner notification for security events.
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Localized Message Option. Allows Appdome users to support global languages in security notifications.
Figure 5: Default User Experience Options for Appdome’s SHA-256 Digest
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Enforce SHA-256 Digest Threat Code™. Appdome uses AI/ML to generate a unique code each time Enforce SHA-256 Digest is triggered by an active threat on the mobile device. Use the code in Appdome Threat Resolution Center™ to help end users identify, find and resolve active threats on the personal mobile devices.
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Congratulations! The Enforce SHA-256 Digest protection is now added to the mobile app -
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Certify the Enforce SHA-256 Digest feature in Mobile Apps
After building Enforce SHA-256 Digest , Appdome generates a Certified Secure™ certificate to guarantee that the Enforce SHA-256 Digest protection has been added and is protecting the app. To verify that the Enforce SHA-256 Digest protection has been added to the mobile app, locate the protection in the Certified Secure™ certificate as shown below:
Figure 6: 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 Enforce SHA-256 Digest has been added to each Mobile app. Certified Secure provides instant and in-line DevSecOps compliance certification that Enforce SHA-256 Digest and other mobile app security features are in each build of the mobile app.
Using Threat-Events™ for SHA-256 Digest Intelligence and Control in Mobile Apps
Appdome Threat-Events™ provides consumable in-app mobile app attack intelligence and defense control when SHA-256 Digest is detected. To consume and use Threat-Events™ for SHA-256 Digest in Mobile Apps, use AddObserverForName in Notification Center, and the code samples for Threat-Events™ for SHA-256 Digest shown below.
The specifications and options for Threat-Events™ for SHA-256 Digest are:
| Threat-Event™ Elements | Enforce SHA-256 Digest Method Detail |
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| Appdome Feature Name | Enforce SHA-256 Digest |
| 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 | |
| Visible in ThreatScope™ | |
| Developer Parameters for Enforcing SHA-256 Digest Threat-Event™ | |
| Threat-Event NAME | SslInvalidMinDigest |
| Threat-Event DATA | reasonData |
| Threat-Event CODE | reasonCode |
| Threat-Event REF | 6801 |
| Threat-Event SCORE | |
| currentThreatEventScore | Current Threat-Event score |
| threatEventsScore | Total Threat-events score |
| Threat-Event Context Keys | |
|---|---|
| message | Message displayed for the user on event |
| failSafeEnforce | Timed enforcement against the identified threat |
| externalID | The external ID of the event which can be listened via Threat Events |
| osVersion | OS version of the current device |
| deviceModel | Current device model |
| deviceManufacturer | The manufacturer of the current device |
| fusedAppToken | The task ID of the Appdome fusion of the currently running app |
| kernelInfo | Info about the kernel: system name, node name, release, version and machine. |
| carrierPlmn | PLMN of the device. Only available for Android devices. |
| deviceID | Current device ID |
| reasonCode | Reason code of the occurred event |
| buildDate | Appdome fusion date of the current application |
| devicePlatform | OS name of the current device |
| carrierName | Carrier name of the current device. Only available for Android. |
| updatedOSVersion | Is the OS version up to date |
| deviceBrand | Brand of the device |
| deviceBoard | Board of the device |
| buildUser | Build user |
| buildHost | Build host |
| sdkVersion | Sdk version |
| timeZone | Time zone |
| deviceFaceDown | Is the device face down |
| locationLong | Location longitude conditioned by location permission |
| locationLat | Location latitude conditioned by location permission |
| locationState | Location state conditioned by location permission |
| wifiSsid | Wifi SSID |
| wifiSsidPermissionStatus | Wifi SSID permission status |
| threatCode | The last six characters of the threat code specify the OS, allowing the Threat Resolution Center to address the attack on the affected device. |
| host | The host that failed minium requirements digest validation |
| DeveventDetailedErrorMessage | Error message |
| extendedMessageText | Extended message |
| certificateCN | Certificate common name |
| certificateSHA1 | Certificate SHA1 |
With Threat-Events™ enabled (turned ON), Mobile developers can get detailed attack intelligence and granular defense control in Mobile applications and create amazing user experiences for all mobile end users when SHA-256 Digest is detected.
The following is a code sample for native Mobile apps, which uses all values in the specification above for Enforce SHA-256 Digest :
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.
xxxxxxxxxxIntentFilter intentFilter = new IntentFilter();intentFilter.addAction("SslInvalidMinDigest");BroadcastReceiver threatEventReceiver = new BroadcastReceiver() { 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);}xxxxxxxxxxval intentFilter = IntentFilter()intentFilter.addAction("SslInvalidMinDigest")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)}x
let center = NotificationCenter.defaultcenter.addObserver(forName: Notification.Name("SslInvalidMinDigest"), 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...)}xxxxxxxxxx[[NSNotificationCenter defaultCenter] addObserverForName: @"SslInvalidMinDigest" 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...) });}];xxxxxxxxxxconst { ADDevEvents } = NativeModules;const aDDevEvents = new NativeEventEmitter(ADDevEvents);function registerToDevEvent(action, callback) { NativeModules.ADDevEvents.registerForDevEvent(action); aDDevEvents.addListener(action, callback);}export function registerToAllEvents() { registerToDevEvent( "SslInvalidMinDigest", (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...) );}x
RegisterReceiver(new ThreatEventReceiver(), new IntentFilter("SslInvalidMinDigest")); 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...) }}x
NSNotificationCenter.DefaultCenter.AddObserver( (NSString)"SslInvalidMinDigest", // 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...) });xxxxxxxxxxwindow.broadcaster.addEventListener("SslInvalidMinDigest", 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...)});x
import 'dart:async';import 'package:flutter/material.dart';import 'package:flutter/services.dart';class PlatformChannel extends StatefulWidget { const PlatformChannel({super.key}); State<PlatformChannel> createState() => _PlatformChannelState();}class _PlatformChannelState extends State<PlatformChannel> { // Replace with your EventChannel name static const String _eventChannelName = "SslInvalidMinDigest"; static const EventChannel _eventChannel = EventChannel(_eventChannelName); 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 Mobile Apps by using Enforce SHA-256 Digest . 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 Enforce SHA-256 Digest
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.
Related Articles:
- How to Prevent abuse of Android AccessibilityService for compromising Android apps
- How to Enforce Secure Certificate Pinning in Android & iOS Apps
- How to Enforce Certificate Roles in Android & iOS Apps
- Check out the Appdome Mobile Games Protection solution page or request a demo at any time.
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.
