DexProtector (https://dexprotector.com) is one of the pioneers in mobile application and library shielding. It protects and obfuscates Android and iOS applications and libraries. Our solution helps you to secure your code and assets against unauthorized or illegal use, tampering, reverse engineering, and cracking.

This sample is to demonstrate how Tamper Notifications mechanism works.

Description

https://dexprotector.com/docs#tamper-notifications

Requirements

• Android Studio or Gradle
• DexProtector Enterpise with a valid license

Configuring

• Set path to Android SDK in local.properties
• Set path to DexProtector Enterprise in build.gradle (project’s root) instead of /Users/developer/DexProtector

Building

Open the project in Android Studio and execute Build -> Generate Signed APK.. command or execute gradle clean assemble from the command line. A protected APK file will be placed into app/app-release.apk if you use Android Studio, if you use gradle via command line a protected file will be available at app/build/outputs/app-release.apk. Either approach you use, we refer to the protected file as app-release.apk below.

Evaluating

Note: All the actions are to be performed from the project's root

Original APK

Install the protected application to a device or an emulator and launch it. There should be a following message displayed: Tamper detection result: false

Updating a file inside of the APK

cp app-release.apk app-release-copy.apk
mkdir assets
echo 1 > assets/sample.txt
zip -g  app-release-copy.apk assets/sample.txt
zip -d  app-release-copy.apk META-INF/*
jarsigner -verbose  -digestalg SHA1 -keystore sample.keystore  app-release-copy.apk  -storepass android -keypass android android
zipalign -v -f 4  app-release-copy.apk  app-release-modified.apk

After installation and launching of app-release-modified.apk there should be a message displayed: Tamper detection result: true

Adding a file into the APK

cp app-release.apk app-release-copy.apk
echo 1 > test.dat
zip -g app-release-copy.apk test.dat
zip -d app-release-copy.apk META-INF/*
jarsigner -verbose  -digestalg SHA1 -keystore sample.keystore app-release-copy.apk  -storepass android -keypass android android
zipalign -v -f 4  app-release-copy.apk  app-release-modified.apk

After installation and launching of app-release-modified.apk there should be a message displayed: Tamper detection result: true

Deleting a file from the APK

cp app-release.apk app-release-copy.apk
zip -d app-release-copy.apk assets/sample.txt
zip -d app-release-copy.apk META-INF/*
jarsigner -verbose  -digestalg SHA1 -keystore sample.keystore app-release-copy.apk  -storepass android -keypass android android
zipalign -v -f 4  app-release-copy.apk  app-release-modified.apk

After installation and launching of app-release-modified.apk there should be a message displayed: Tamper detection result: true

Resigning with a different certificate

Notifications will be fired with the following settings only (otherwise the protected application will fail to start because of the DexProtector's internal integrity checks that prevent starting of a modified APK):

<integrityControl>
  <checkCertificate>off</checkCertificate>
</integrityControl>

Prior to this step, please delete the application from a device/emulator

cp app-release.apk app-release-copy.apk
zip -d app-release-copy.apk META-INF/*
jarsigner -verbose  -digestalg SHA1 -keystore test.keystore app-release-copy.apk  -storepass android -keypass android android
zipalign -v -f 4  app-release-copy.apk  app-release-modified.apk

After installation and launching of app-release-modified.apk there should be a message displayed: Tamper detection result: true