How to Enforce SHA-256 Digest in Android & iOS Apps

Last updated May 21, 2024 by Appdome

Learn to Enforce SHA-256 Digest in Mobile apps, in mobile CI/CD with a Data-Driven DevSecOps™ build system.

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 Enforce SHA-256 Digest :

To use Appdome’s mobile app security build system to Enforce SHA-256 Digest , you’ll need:

Enforce SHA-256 Digest on 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:

  1. Upload the Mobile App to Appdome.

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

    2. Upload Method: Appdome Console or DEV-API
    3. Mobile App Formats: .ipa for iOS, or .apk or .aab for Android
    4. Enforce SHA-256 Digest Compatible With: Obj-C, Java, JS, C#, C++, Swift, Kotlin, Flutter, React Native, Unity, Xamarin, and more
  2. Build the feature: Enforce SHA-256 Digest .

    1. Building Enforce SHA-256 Digest by using Appdome’s DEV-API:

      1. Create and name the Fusion Set (security template) that will contain the Enforce SHA-256 Digest feature as shown below:
      2. fusion set that contains Enforce SHA-256 Digest

        Figure 1: Fusion Set that will contain the Enforce SHA-256 Digest feature
        Note: Naming the Fusion Set to correspond to the protection(s) selected is for illustration purposes only (not required).

      3. Follow the steps in Sections 2.2.1-2.2.2 of this article, Building the Enforce SHA-256 Digest feature via Appdome Console, to add the Enforce SHA-256 Digest feature to this Fusion Set.

      4. Open the Fusion Set Detail Summary by clicking the “...” symbol on the far-right corner of the Fusion Set. Copy the Fusion Set ID from the Fusion Set Detail Summary (as shown below): fusion Set Detail Summary image

        Figure 2: Fusion Set Detail Summary
        Note: Annotating the Fusion Set to identify the protection(s) selected is optional only (not mandatory).

      5. Follow the instructions below to use the Fusion Set ID inside any standard mobile DevOps or CI/CD toolkit like Bitrise, App Center, Jenkins, Travis, Team City, Circle CI or other system:
        1. Build an API for the app – for instructions, see the tasks under Appdome API Reference Guide
        2. Look for sample APIs in Appdome’s GitHub Repository
    2. Building the Enforce SHA-256 Digest feature via Appdome Console

      To build the Enforce SHA-256 Digest protection by using Appdome Console, follow the instructions below.

      1. Where: Inside the Appdome Console, go to Build > Security Tab > Secure Communication section.
      2. How: Check whether is toggled On (enabled), otherwise enable it . The feature Enforce SHA-256 Digest is enabled by default, as shown below. Toggle (turn ON) Enforce SHA-256 Digest , as shown below.
        If needed, Customize the Threat Notification to be displayed to the mobile end-user in a standard OS dialog notification when Appdome Enforces SHA-256 Digest .
        Enforce SHA-256 Digest  option

        Figure 3: Enforce SHA-256 Digest 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.

      3. When you select the Enforce SHA-256 Digest you'll notice that your Fusion Set you created in step 2.1.1 now bears the icon of the protection category that contains Enforce SHA-256 Digest

        Fusion Set applied Enforce SHA-256 Digest

        Figure 4: Fusion Set that displays the newly added Enforce SHA-256 Digest protection

      4. Select the Threat-Event™ in-app mobile Threat Defense and Intelligence policy for Enforce SHA-256 Digest :
        1. Threat-Events™ OFF > In-App Defense

          If the Threat-Events™ setting is cleared (not selected). Appdome will detect and defend the user and app by enforcing Enforce SHA-256 Digest .

        2. 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™ for Enforce SHA-256 Digest Intelligence and Control in Mobile Apps.

        3. 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 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 Intelligence and Control in Mobile Apps.

      5. Click Build My App at the bottom of the Build Workflow (shown in Figure 3).
    Congratulations!  The Enforce SHA-256 Digest protection is now added to the mobile app
  3. 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: Enforce SHA-256 Digest  shown in Certificate secure

    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 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
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
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.



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:

Related Articles:

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.

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