---
title: Reverse Engineering Case Studies — REA
url: https://rea.tools/showcase/
---

[Home](https://rea.tools/) / Showcases

# REA case studies.

Android, games, Electron and a CTF challenge, with code, figures and
checked results.

Android · APK analysis

## How an authenticator generates a login code

Find Aegis's six-digit code calculation in its released APK. Trace
the generating methods with REA, then move a demo clock to see why
the code changes every 30 seconds.

APK 
Generating code 
Recovered rule 
Adjustable clock

[Read the Android case study](https://rea.tools/showcase/aegis/)

CTF · Native analysis

## Solve a CTF flag checker

Inspect an easy DownUnderCTF challenge with REA. Find its checking
functions, turn masks and sums into equations, then verify the
solved flag with the original program.

Binary 
Checking code 
Equations 
Correct!

[Read the CTF case study](https://rea.tools/showcase/ctf/)

Native · Reconstruction

## DX-Ball's sound-pan calculation

Recover a sound-pan calculation from a 1996 Windows game. REA's
instructions, caller references and numeric constants lead to a
small C function, checked against the original behavior and all 63
compiled bytes.

Executable 
REA findings 
Recovered C 
Validation

[Read the DX-Ball case study](https://rea.tools/showcase/dx-ball/)

Electron · Feature tracing

## How Notion copies text and HTML

Trace a page-facing API through Notion's packaged JavaScript.
Follow its IPC wrappers to the system clipboard, then see how a
small HTML marker keeps rich block data connected to a copy.

Packaged app 
Exposed API 
IPC wrappers 
Clipboard

[Read the Notion case study](https://rea.tools/showcase/notion/)

PC-98 DOS · Reconstruction

## How TH04 aims a ring of bullets

Inspect the original 16-bit angle helper with REA. Match its
multiply, divide and coordinate operations to readable C++, then
see how they produce a ring aimed at the player.

Original DOS code 
REA instructions 
Angle calculation 
Bullet ring

[Read the TH04 case study](https://rea.tools/showcase/th04/)

RL environments

## Build RL environments with REA

Record a web app session, turn its API into tools, and export an
environment an AI agent can use. Run it with AgentEnv, then add
tasks and reward checks for RL training or evaluation.

[Read the guide](https://rea.tools/guides/rl-environments/)
·
[Watch the video](https://x.com/reatools/status/2112574822584918075?s=20)

## Step-by-step guides

The guides walk through a native calculation, an Electron export and a
browser request. Each starts with a prompt and a concrete target.

[Read the guides](https://rea.tools/guides/)