ProGuard and their implications on an Android device

Modern-day mobile applications are susceptible to a wide range of security threats. In a way, it compels developers to adopt the best measures when it comes to dealing with security threats. An alarming figure is that in less than 50 % of the financial apps that are available in the Android market security measures are installed in place. What it means is that these apps are vulnerable to a series of threats, including app clones, IP threats, sensitive loss of data along with reputational damage among a few others. Another important point to take into account is the app’s performance. Removing unnecessary applications along with codes from your apps would make it faster. For open-source applications code, obfuscation is an important pointer to consider.

Numerous forms of tools are there when it comes to Android studio and the name that tops the list is Proguard. Let us understand what it has to offer and a piece of concise information about the same is vital before you go on to take a decision.

ProGuard and their features

There are three major functions that are undertaken by ProGuard that is shrinking, optimization, and obfuscation. It happens to be a free tool that can go on to shrink optimize and obfuscate the Java files. Normally it is used in Java applications and as discussed earlier it is part of the Android applications too. Reverse engineering is possible but it is not something that is beyond the scope of implementation.

An Android application turns out to be an easy target for reverse engineering which does make it easier for a developer to opt for ProGuard as a basic form of a security measure. With minimum configurations, it is an ideal way to secure your app. Take note of the fact that this turns out to be a basic type of security tool and some experts could consider it to be a multi-layered approach from a security point of view. It goes on to eradicate the unused variables and a notable feature is that it goes on to reduce the application size with a command line tool.

To reduce the app size the role of ProGuard is prominent, as the applications are optimized. As discussed earlier it is achieved by a series of techniques. Let us understand them in detail


The process of shrinking goes on to reduce the size of the APK files. It enables to detect the unused variables, methods, or classes. From the libraries and the applications, the unused codes are being removed. There are a couple of ways by which you can accomplish the process of shrinking

  • Resource shrinking- it goes on to remove the unused resource files from an application along with the library independencies which is referred to as resource shrinking
  •  Code shrinking- goes on to remove the unused variables or methods from the application or the library.


The process of optimization indicates that you need to optimize the by code. Any form of unused instructions could go on to have a negative impact on the use of an app. If there is a duplicate code at this stage it is removed and long instructions could be replaced with the smaller ones and they are being removed.


Is the process where the code is made unsuitable to be read. For example, a third party who has gone on to gain unauthorized access to the app will not be able to make sense of the code. After the removal of the unused codes, or methods they are renamed using random characters. It is done so as to hide the original intent of the code segments from the hackers.

ProGuard and the benefits of their implementation

When it comes to ProGuard Android there are a series of benefits associated with their implementation as follows

  • A compact configuration- it has a template-based configuration when you compare it to the other Jave obfuscators. This happens to be one of the major benefits of ProGuard. You could go on to incorporate a series of few intuitive command line options or a simple configuration file to rename the same.
  • Protection against static analysis- the hackers are known to use statistical analysis when it comes to obtain the source code of an application. Here the source code along with the control flow could be analyzed by the hackers to find out how the app is going to work without tunning it. It even goes on to shield the app against any form of decompiles.
  • Reverse engineering works out to be a difficult task- the moment you go on to apply ProGuard rules the process of reverse engineering turns out to be a difficult task. There is a possibility that the critical data can be leaked and gives access to the application for negative purposes. It turns out to be a stumbling block when it comes to the question of reverse engineering methods.
  • The efficiency of the applications is enhanced- with Proguard the efficiency of applications tends to improve at a considerable level. With its optimized features it enhances the application features, Even the application with Proguard is enabled in an effective manner of sorts.
  • Specifies the dead code- With Proguard it is possible to figure out the code that is no longer in use and you can end them removing from the source code.

To conclude incorporating ProGuard is expected to reduce the size of the files. In short it can reduce the size of the application from 20 % to 90 %. Not only it goes on to discard the unused sources along with applications from your code but it results in a complete package with smaller footprints. Another benefit if the same is that it can go on to possess several megabytes within the shortest time frame possible. It is not that there are only benefits related to their usage as there are some pitfalls that you have to evaluate before you use them.

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