Basic Operation

The aardefender tool works on compiled Java classes, like the apkdefender tool operates on the application bytecode. aardefender tool is compatible with the supported Java versions up to Java 17. As much as possible of the bytecode is translated to native code. aardefender tool takes an unprotected Android archive (AAR) as input and produces a corresponding protected archive as output. The protected archive file is named <original-name>-protected.aar and placed in the same directory as the original archive.

During protection, the bytecode is translated to native code, and anti-tamper protections and obfuscation then applied. As with apkdefender tool, there are a number of conditions that prevent translation of specific classes and methods. Some of those methods are detected and excluded from translation by default, but often, exclusion of some additional packages, classes, or methods must be configured to maintain the application stability.

To enable good protection and accurate callgraph analysis, define the library API in configuration so that API methods are not fully wiped from the bytecode. Also give an approximate calling score to the API methods to enable evaluation of effects on performance. For more information refer to Public API methods and scores .

aardefender provides informational output from the execution steps to the stdout. More extensive debug output is collected to aardefender.log file in the current working directory.

aardefender operation is controlled with configuration directives given via command line and a JSON configuration file.

Invoking the Tool from the Command Line

**The aardefender tool offers a command line interface. The followingexamples demonstrate the tool usage on Linux.

To protect the application, execute the following command:

aardefender -c <path-to-configuration-file> sdk-release.aar

A protected application app-release-protected.apk is produced.

Command line options

The supported command line options are listed in the following table:

JSON Configuration file

A sample of the supported configuration file format and options is given below.

{
   "general_configuration": {
       "enable_debugger_detection": true,
       "enable_root_detection": false,
       "library_name": "sample_library"
   },
   "protection_scope": {
       "exclude_classes": [],
       "exclude_methods_from_translation": [],
       "exclude_packages": [],
       "exclude_translated_methods_from_wiping": [],
       "include_packages": [],
       "library_api_methods": {"api_method_1": 2, "api_method_2": 5}
   }
}

The configuration file format type is JSON. The allowed elements are explained in the table below. If an optional element is not given, the tool will use the specified default value.

General Configuration

Protection Scope

Public API methods and scores

The library_api_methods option is used to declare the public API methods that must not be wiped from the aar library, and their calling scores. The scores represent roughly the number of calls during one application process lifecycle, for example:

• For application object onCreate() the score is 1.
• For activities onCreate() and onDestroy() a few more callscould be defined, as there would be some navigation back and forth.
• For known low frequency API functions the score should be given as~1-10, to ensure a check will be injected.
• For medium frequency functions a suitable score would be 30-100.
• For high frequency functions where checks must not be injected the score should be exceeding 500 which is the default maximum score for adding explicit checks.

Alternatively, use annotations to define the API methods. For more information refer to section Annotations.