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Reverse Engineering: The Definitive Guide To Know About It

You might have heard this term a lot. This term is used in various subjects such as mechanics, software, and even Psychology. In this article, we are going to talk about Reverse Engineering in the Engineering field, more specifically in the computer field.

Forward Engineering:-

Before moving any further let’s look at what Forward Engineering is. 

In the software development lifecycle we have a pretty simple process as we first start from the specification phase, then analysis, followed by design and finally implementation, and your product is ready. That’s how forward engineering works.

Define Reverse Engineering:-

Reverse engineering is a process, where one disintegrate an object or a program and then re-integrate to examine the possibilities that you can achieve with the technology.

Therefore, it is fair to say that, this was introduced to extract knowledge behind the technology. 

Reverse Engineering

They were first used by scientists as they disintegrated a human DNA to seek knowledge about the working of the specie.

But then it was used by programmers and developers as they disintegrate a program or technology respectively to build a new technology which may or may not be completely different than its predecessors, but it can be boiled down to the disintegrated program.

If you are a software developer or an aspirant software developer, you might have heard the term Decompiler a lot. It is a tool that works on the concept of reverse engineering, in this Machine Code is translated to a programing language such as Java or C++. This is used to study the disintegrated code and work accordingly.

What are the three stages of Reverse Engineering:-

Reverse Engineering stages

If you want to be a software expert then this guide is like a magical broom for your Reverse Engineering wisdom. We are going to lay facts and tips about the three stages of Reverse Engineering.

So, let’s talk about the three main stages of Reverse Engineering.

Implementation Recovery/Redocumentation:-

Unlike forward we are not working from the scrap, we have a finished product that needs our attention. So in this stage, we have to go through the pre-written code and examine it to extract knowledge about the application.

Redocumentation is an OG form of reverse engineering and according to many programmers, it is an unintrusive, weak, and bleak form of restructuring, which is an evident use of Reverse Engineering.

This knowledge is like a first nail in the coffin. This knowledge will help you in creating an image in your mind which will eventually help you in the long run. 

After going through the codes, you need to insert the knowledge(database structure) in a modeling application or tool. 

To do that follow these steps:-

Step 1: First of all we should be looking to create a provisional object type, to do that we are going to refer every data unit as a separate object. It is recommended that you look at all the data units and give every object corresponding to it the same name.

Step 2: After naming every object, we should create a provisional relationship type. This is used to create a separation between CODASYL and others. So, you are portrait the applications related to CODASYL committee as relationship type and others as defer relationship type.

Step 3: The next step is to make provisional hallmarks/attributes. To create a hallmark, you need to assign all object types to every data element in the legacy system. And you need to designate non-null restrictions, data-types, and lengths if the information is available.

Step 4: Finally, you should mark keys such as primary, candidate, secondary, etc.

There are tons of tools one can use for redocumentation such pretty printers(which display a code listing in an improved form) or diagram generator, which is used to create diagrams directly from code, reflecting control flow or code structure.

Design Recovery:-

This is where you need to be creative. You need to disintegrate and then re-integrate the mechanics of the database and then proceed with your needs and skills. 

In Reverse Engineering we accumulate the information extracted from the source code or the disintegrated product and the external information to identify meaningful higher-level abstraction which can not be obtained by just examining the system.

Design Recovery is generally used to create a distinguishing factor between the later and the prior code/product. One has to make sure that Design Recovery provides all the information required to understand what the program is, how it works, why it does, so on, and so forth.


Now, after acquiring all the required knowledge, it is time to reconstruct and transform it from one respective form to another on a relatively same abstraction level and at the same time making sure that the subject’s function and semantics are preserved.

Nowadays, reconstructing/re-engineering is done as doing some twitches in the program by altering the source code to improve the prior structure of the program, but it’s not limited to that only.

This term has a broader meaning that recognizes the application of similar transformations and recasting techniques in reshaping data models, design plans, and requirement structures.

Many a time, you don’t need to know the meaning of the code, but you can reconstruct it with just the knowledge of its structure.

One thing that you should always keep in mind that reconstructing/re-engineering is an alteration and not modification. Reconstructing can be performed to do that, but it is not necessary.

However, it may lead to a better understanding and observation of the subject, which will eventually allow us to improve the physical state of the subject system concerning the preferred standard. 

Re-engineering may or may not involve both the forward and reverse engineering technologies.

What are the 8 steps to Reverse Engineering-Compressed Version of the three stages:-

After knowing the three stages of Reverse Engineering it is the time to implement it in the practical world. This more so a guide that you can do to reverse engineer, therefore, it is advisable to follow this guide.

Collect Knowledge: Before disintegrating the program you must have abundant information about it, therefore, in this step you are going to collect information from a different source about the manufacturer and the program.

Examine that knowledge: After collecting the information you need to study all the information with respect to the code, in order to eradicate the alien terms by learning about them.

Increase the standards of the document: This step is optional, as in this you should try to increase the standards of the document if it’s not up to it with the help of Reverse Engineering. 

Note the structure: It’s time to examine the program’s structure as the structure is very important in a program and reverse engineering as well. So, in this step, we are going to create charts and patterns to study the structure.

Make note of the attributes: You should make note of the attributes and the functions used in the program with the help of tables and charts.

Examine and create the flow of data: Now you should create a structure with the help of the data that you have obtained from the first second and the third step, after which you need to examine and record the data’s structure.

Examine the Design: The created design or document is examined in these steps. The examination is conducted by the experts multiple times before the final step.

Patent the Work: Finally, you are going to register your work with quite a few documents such as SRS, history, design document, etc. After which the document is said to be adequate for future use.

Uses of Reverse Engineering:-

Reverse Engineering: The Definitive Guide To Know About It

Reverse Engineering is a very broad term and you can accomplish a lot via this method od engineering, here are a few uses of using Reverse Engineering.

Increases ones knowledge:-

As mentioned earlier, reverse engineering has three steps, and the first one which is documentation, one needs to study and jot down different structures and codes. Which will eventually increase his/her knowledge.

Update the product:-

Reverse Engineering’s reengineering is also used to update the outdated product. In this, some quality from the previous models is used and is made adequate to meet the current demands.

Fix the fault:-

Reverse Engineering: The Definitive Guide To Know About It

Reverse Engineering is also used to fix the fault of a product or a set of codes. This can be beneficial in two ways. Either you are creating a product and want to fix any vulnerabilities you or you can change faults in previous programs. 

Increase the value of the product:-

The value of a product depends on two things, its efficiency and the capital/time takes to create it. Reverse engineering tick both the boxes.

Some of you might argue that reverse engineering takes more time than the forward engineering, but the thing is you don’t need reverse engineer the whole program, you can reverse engineer a portion of it as well. This portion RE is used a lot while upgrading or updating a program.

Banter your creative bones:-

This just like the first point. As, apart from increasing your knowledge, reading and understanding more codes will increase your creative power as well.

Not only that, one can be more creative as he goes on a journey, in which he will learn more complex programs and then break them. This was why Reverse Engineering came into existence.

Demerits of Reverse Engineering:-

Even though Reverse Engineering has tons of uses and advantages it still has some disadvantages which we are going to talk about in this section.

You may face legal charges, it will be more clear to you later in this article. But for now, you should keep in mind that Reverse Engineering is legal but with some concern.

So, it is better for you to go through the laws on copyrights and patents of your region before going through the process.

Very choosy, as mentioned earlier Reverse Engineering has three stages out of which one is where you need to collect all the information available and choose the right information is like choosing the diamond from the coal mine.

If you are thinking that reverse engineering can save your research work then you need to give it another shot.

Objectives of Reverse Engineering:-

You might have had the idea of why Reverse engineering was made, which is to increase the overall comprehensibility of the system for both maintenance and new development.

But apart from the conventional practice here are six key objectives that will guide its direction as the technology matures:-

Cope with complexity:- One of the best and the most efficient ways to unravel a program is to do reverse engineering as the programs are very complex and big.

Reverse Engineering combined with the CASE environment provides you with a way to extract relevant information which will help the decision-makers to control the process and the product in system evolution.

Have different views:- The most conservative technique used by the programmer to create Graphic representation was with the help of the dataflow diagram, it is used to extract his/her view out of it.

But creating and maintaining then is very difficult. However, because of the advancement and the introduction of Reverse Engineering is now being replaced with the control-flow diagram, structure chart, and entity-relationship diagram. Which eventually helps us to have a different and alternative view on the topic.

One can also create different perspectives with non-graphical representation with the help of reverse engineering.

Recover lost information:- First of all, I want to make one thing clear, I am not against the concept of preserving data and Reverse Engineering is not an alternative to it.

But sometimes because of the complexity and the volume of the program, some information might get loss about the system design.

Reverse engineering is a way by which one can extract knowledge from the existing document because of the current design pattern as it helps us to understand what they do or how their individual programs interact as a system.

Examine the side effects:- Sometimes, unintentionally one creates side effects both in the initial steps and the further steps. These side effects can alter the system’s performance in a way that is bad for our system.

With the help of reverse engineering, one can easily observe beyond those we can obtain with just forward engineering as it can help the developers to attain anomalies and problems before users report them as bugs.

To synthesize higher abstraction:- As mentioned earlier, reverse engineering provides the developers with a wide range of views and these alternative views can be used to synthesize a higher level of abstraction.

Many companies try to do attain a higher level and if you are one of them, then you should also start adding reverse engineering to the mix of expert-system technology.

Re-use: Reverse Engineering can simplify the reusability. As programmers always face issues while reusing the program, but with the introduction of Reverse Engineering one can easily break the program and reuse it.

Is Reverse Engineering Legal?

Is Reverse Engineering Legal

The legality of Reverse Engineering has been a matter of discussion for the past few years.

However, if we look at the official documents of the US governing council you will see that Reverse Engineering is not labeled as a malicious or illegal practice. Even if we look at the Economic Espionage Act it is clearly evident that reverse engineering is not illegal. 

Even though there is no specific law for Reverse Engineering, but they are some laws that challenge the practice of reverse engineering. Let’s look at a few laws concerning the Legality of Reverse Engineering.

Copyright Law:-

Copyright Law is often criticized by engineers who want to do reverse engineering. As per this law, one can be stated guilty for using the intellectual property of someone even if they use a small portion of their whole code in their reverse engineering arsenal.

According to this law even extracting ideas from a certain code is illegal and the engineer will be considered guilty for violating the non-disclosure contract.

Digital Millenium Copyright Act(DMCA):-

Reverse Engineering: The Definitive Guide To Know About It

Digital Millenium Copyright Act or DMCA doesn’t conclude anything against Reverse Engineering. However, intellectuals have always argued that DMCA limits the use of reverse engineering under technological protection measures.

Its meaning and its reference to Reverse Engineering is a pretty blur as some might argue that this law is only applicable to digital rights, on the other hand, some say that it also accumulates few methods such as obfuscation, authentication handshakes, etc.

Electronic Communications Privacy Act(ECPA):-

ECPA again targets Reverse Engineering, according to it, being a hurdle in the flow of communication is a malice act. This means that you can’t do reverse engineering on a network packet. 

How can I use Reverse Engineering Legally?

Even though reverse engineering is not a crime in itself, still there are pretty scenarios where using Reverse Engineering can drag you to the cote.

But how can you ensure that you are legally correct while doing Reverse engineering? In this section, we are going to answer just that. Therefore, you need to this pretty carefully and if possible make a note of it.

The first thing that you should do is ask for legal guidance, and for that, you should consult a lawyer.

Never use the copyrighted copy, always try to make a copy of the document at the intermediate level in the creation of the product.

Do not use illegal Software, what I mean with this is that the software that you are using for reverse engineering must be acquired from a legitimate source.

The software mustn’t be a cracked version, that you have downloaded for free instead of buying it from the manufacturer. So, if someone claims to be the owner of your creation, the legit software will ensure that you don’t fell into any other trap.

Do not include authentication handshakes, code obfuscation, and other terms coming under technical protection measures. As they are used to define the software and using them is a clear disobedient to Copyright law.

Do not use a single line of the code, as mentioned earlier under Copyright law one, you can not use a single portion of the code. Sometimes, even the techniques are forbidden.

So, the best option would be to give clear instructions to your Reverse engineering team to study the code properly and then write a sperate code with the knowledge about the prior. Make sure to appoint creative minds for this job.

You may like to read our guide on What is VRM and How Does VRM Work.

Is Reverse Engineering ethically right?

Now, after seeking legal wisdom, one needs to see whether the technique he/she is using is ethically right or not. This notion that Reverse Engineering is unethical has been very prominent in our society for quite a few years.

Many believe that Reverse Engineering is unethical because you are stealing someone’s intellectual property as they have a proper research and development team for developing a program and now someone will steal their hard work in the name of Reverse Engineering.

On the other hand, some claim that Reverse Engineering is going to increase the speed of development and advancement exponentially. According to them if it’s not illegal then how can it be unethical.

What do you think? Let us know in the comment section.

Important Points:-

Reverse engineering is a process, where one disintegrate an object or a program and then re-integrate to examine the possibilities that you can achieve with the technology.

Reverse Engineering was introduced to attain knowledge of different hardware and software and to know the technology behind it.

Three stages of Reverse Engineering are Implement Recovery/redocumentation, design recovery, Reconstruction/Reengineering.

Reverse Engineering can be helpful to you in multiple different tasks such as to increase your programing language, update the product, fix the fault, etc.

There are few demerits of Reverse Engineering as well such as your product created due to reverse engineering can be legally challenged and you need to a lot of research before starting any project 

Even though there is no law against Reverse Engineering in the US law book, however, it can still be challenged via other laws such as Copyright Law, DMCA, and ECPA.