Gizmo II

Prerequisites & Requirements

• Godot Engine Internals:
  • Understanding how Godot handles Script Encryption and the role of the .pck file format.
  • Knowledge of how game engines embed resources and how gdsdecomp interacts with them.
• C++ & Source Code Analysis:
  • Ability to read Open Source C++ code (specifically the Godot Engine source on GitHub) to identify specific function signatures and variable names ( e.g ., script_encryption_key) that handle decryption.
• Reverse Engineering & Debugging:
  • Proficiency with IDA Pro (or similar disassemblers) to navigate the binary.
  • Understanding x86/x64 Assembly to identify how arguments are passed to functions.
  • Experience with Dynamic Debugging (setting breakpoints, stepping through code) to inspect memory registers at runtime.
• Cryptography Basics:
  • Understanding AES Encryption concepts (specifically AES-256) to recognize what a 256-bit key looks like in memory or static data sections.

What will you learn?

• Cryptographic Key Extraction:
  • Learning how to extract AES-256 encryption keys embedded within a compiled binary.
  • Using Source-Code Assisted Reversing : Using the official Godot source code as a map to find specific routines (like get_script_encryption_key) inside the target executable.
• Hybrid Analysis Techniques:
  • Combining Static Analysis (finding string references and functions in IDA) with Dynamic Analysis (hooking/breaking at the function call) to dump the key from memory.
• Decryption & Unpacking:
  • Learning how to bypass asset protection by feeding the recovered key back into tooling (gdsdecomp) to unlock and decompile the hidden scripts.

Tools

• IDA Pro:
  • Used for both Static and Dynamic Analysis . It allows you to search for string constants associated with Godot's encryption routines, view the assembly to locate the script_encryption_key variable, and set breakpoints to retrieve the key during execution.
• gdsdecomp (Godot Decompiler):
  • The specialized tool used to reverse the Godot package. Unlike the previous level, this tool is used here with the --key argument to decrypt the protected resources before decompiling the PlayerMovement.gd script.
• Godot Engine Source Code (GitHub):
  • Used as a reference manual to locate the specific C++ implementation details of the encryption mechanism, providing the search terms needed to find the relevant code in IDA.