What is reverse engineering?

Reverse engineering is a process that entails analyzing a software system to gain insights into its structure, functionality, and behavior. It involves extracting information from artifacts like executable files, libraries, and configuration files, at different levels of abstraction, such as the code, design, and specification levels. Manual tools like disassemblers and decompilers, as well as automated code analyzers and generators, facilitate this process.

In the gaming and software industry, reverse engineering plays a crucial role in understanding proprietary systems, ensuring compatibility across platforms and operating systems, and creating mods and fan-made content. It also aids in software analysis and security, identifying vulnerabilities for safer user experiences. Moreover, reverse engineering helps preserve classic games and applications, allowing future generations to experience the technological and entertainment evolution.

However, ethical and legal considerations are vital when engaging in reverse engineering activities, ensuring responsible and legitimate use of this powerful tool. As we explore its applications in the subsequent sections, we will uncover its significance in shaping the gaming and software industry and preserving digital artifacts for posterity's enjoyment. Together, we will venture into the world of reverse engineering and its transformative impact on our digital landscape.

The Toolkit.

Manual Tools: Disassemblers, Decompilers, Debuggers, and Hex Editors

Disassemblers are critical tools in reverse engineering that transform machine code into human-readable assembly language. They enable analysts to decipher the logic and functionality embedded in binary code. For instance, when reverse engineering a game's executable, a disassembler can unveil the assembly instructions governing specific game mechanics.

// Decompiled javascript code for enemy AI behavior
function enemyAI() {
    if (playerIsNear()) {
        if (isAggressive()) {
            attackPlayer();
        } else {
            fleeFromPlayer();
        }
    } else {
        patrol();
    }
}
Ghidra is an open source reverse engineering tool developed 
by the National Security Agency. 

Decompilers attempt to revert compiled code (like C/C++) back into a higher-level programming language, providing insights into code functionality. Suppose a game's physics engine is implemented in compiled code. A decompiler might produce a version of this code in a more human-understandable language, aiding in understanding the physics logic.

Debuggers allow real-time analysis of executable code, offering insights into the program's execution flow and memory usage. When dissecting a game, debuggers can help trace how variables change during gameplay, aiding in understanding how certain features are implemented.

Hex editors offer direct manipulation of binary files, like game assets. They are handy for modifying textures, models, or sounds within a game. For example, a hex editor could be used to tweak the inventory of in-game values.

Offset   Inventory_Cash
0000      100.20
Offset   Inventory_Cash
0000      9999.99
ImHex is an open-source hex editor designed for 
inspecting and editing binary data

Automated Tools: Code Analyzers, Code Generators, and Code Converters

Automated code analyzers utilize algorithms to scan codebases for patterns, vulnerabilities, and issues. In the context of reverse engineering, these tools can identify potential security flaws, enhancing the software's robustness. For instance, analyzing a game's networking code might reveal vulnerabilities that need addressing to prevent exploits.

Code generators automate the creation of code based on predefined patterns or requirements. In reverse engineering, these tools can aid in generating higher-level code from lower-level languages like assembly. If a game's rendering logic is deciphered in assembly, a code generator could assist in creating equivalent code in a higher-level language for easier modification.

Code converters facilitate the translation of code between different programming languages. When reverse engineering a game, these tools can help translate sections of assembly code into more modern programming languages, making it easier to work with or adapt the code.

These tools, whether manual or automated, are vital for reverse engineers to navigate the complex landscape of a software system and gain a deep understanding of its components and functionality.

Ethical and Legal Considerations

Engaging in reverse engineering activities requires careful consideration of ethical and legal implications. Respecting the responsible and legitimate use of this powerful tool is vital. Adhering to legal guidelines and ethical standards ensures that the process contributes positively to the industry and digital preservation efforts.

Conclusion

In this exploration of reverse engineering, we've peeled back the layers of software systems, delving into their intricate architecture, functionality, and behavior. From dissecting executable files to unveiling design choices, the process offers a profound glimpse into the digital world's underlying mechanisms. Through the interplay of manual tools like disassemblers and decompilers, as well as automated code analyzers and generators, we've witnessed how reverse engineering can transform complexity into comprehension.

Reverse engineering's significance reaches far beyond mere technical curiosity. It's a cornerstone in the gaming and software industry, enabling us to fathom proprietary systems, bridge platform divides, and create innovative fan-made content. But it doesn't stop there – this methodology enhances software analysis, bolsters security, and ensures a bridge to the past by preserving the legacy of beloved classics.

As we move forward, our exploration evolves. The next horizon in our journey encompasses emulation and preservation, where the digital torch is passed to ensure the continued existence of iconic games and applications. Emulation, like reverse engineering, unveils its own intricate toolkit, enabling us to breathe life into the software of yesteryears, and ensuring future generations can engage with the technologies that shaped our digital world. Through the lens of emulation and preservation, we'll continue to navigate the intersection of technology, nostalgia, and progress, unraveling new layers of our digital heritage.

Resources

Conley, J., Andros, E., Chinai, P., Lipkowitz, E., & Perez, D. (2004). Use of a Game Over: Emulation and the Video Game Industry, A White Paper. Northwestern Journal of Technology and Intellectual Property, 2(2), 1.

Dale, R. (2007, August 8). RLG DigiNews: Volume 5, Number 3. https://worldcat.org/arcviewer/1/OCC/2007/08/08/0000070519/viewer/file1503.html

Stuart, K. (2020, April 16). Preserving old games is a service to humanity. The Guardian. https://www.theguardian.com/technology/2007/jul/12/games.comment

http://pdf.textfiles.com/academics/conley.pdf
View of Keeping the game alive: Evaluating strategies for the preservation of console video games. (n.d.). http://www.ijdc.net/article/view/147/209