5 Mistakes to Avoid While Using ProGuard Security

Charlotte Miller

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The proguard, which is a freely available java class file shinker, optimizer, obfuscator and pre verifier. Before rolling them out into production, it securely saves android-based programs. Nevertheless, there are also typical shortcomings that developers commit while employing Proguard undermining app’s safety. This article will focus on five major mistakes that should be avoided.

  1. Not Configuring ProGuard Properly

The most prevalent mistake is not adjusting ProGuard correctly. However, for developers only certain classes, fields, and methods must be marked to avoid ProGuarded unnecessarily deleting or changing them, thereby possibly crashing the program. Carefully go through the documentation, configure ProGuard and leave all necessary classes and methods in place. Failing to follow it may result in run-time errors and vulnerability.

  1. Forgetting to Shrink the Code

The obfuscated code is more difficult to understand while the shrunken code is smaller but still effective as it removes unnecessary fields within the class structures, unused variables, empty constructors, comments, and methods not in use. It assists enhance performance and security. Without shrinking, this makes it easier for attackers to decompile the code so as to gain insight into app logic and identify breaches. For optimum security benefits ensure shrinking and obfuscation are activated.

  1. Ignoring post obfuscation testing of the app

Testing the app thoroughly once it is obfuscated with proguard is very important for checking that all is working without any bug. Some problems are likely to be realized runtime, when some code elements may have been deleted or renamed. Intensive testing catches glitches and crashes prior going live and plugging vulnerabilities where possible.

  1. Forgetting to Obfuscate Third Party Code

The app code obfuscation should also include 3rd party libraries as well as additional code incorporated in the application. Third party code that is unmodified can assist attackers to know app behavior as they will see the decompiled code and not the obfuscated one. Ensure that your ProGuard configuration covers all externally referenced JAR and class files for full-on obfuscation.

  1. Failure to update ProGuard configuration over time

With time, a new application emerges every day with classes, methods as well as other code components which are meant to support additional features and functionalities. Nevertheless, the ProGuard configuration file giving information on what aspect of the codes to retain in full without compression, compress or obscure may not be updated on time. These newly added classes are not covered by an old ProGuard configuration. This could cause problems such as removal of classes and methods during the build leading to build failure or runtime crash.


The use of Proguard android is very important in enhancing security as far as android applications are concerned, however, only if it is used appropriately. Indeed, it is essential for one to spend time setting, testing and maintaining the ProGuard settings so as achieve optimized security benefit. In this respect, it is prudent to avoid some of the issues highlighted earlier such as incomplete configuration, no testing or obsolete policy to make sure that there are minimum security gaps while at the same time promoting efficient and safe development process. Carefully and patiently, Proguard ensures it strengthens the apps by making them resistant to reverse engineering and hacking.