KHUX API Reverse Engineering

This repo contains tools I've been using to successfully view and modify API traffic for KHUx/KHDR. I do not condone the use of my tools to hack or gain an unfair advantage in the game; these tools are only available to gain insight on how the game functions.

Client

This also includes a terminal client, able to connect with the real game server and login. All you need is the UUID associated with your account.

Backup

To backup your user data, you'll need your UUID, device type, and NodeJS installed to your system. Then open a terminal in the same directory as this project and enter the following commands:

NOTE: At this current time, backing up your account will shadowban your account. This means you cannot participate in rankings.

npm install # Only needs to be run one
node index.js --backup <insert uuid here> --device <number> --os-version <os version> # Don't include the <> in your command

Note: If you want to backup ALL of your data (quest completion) and don't care if you get shadowbanned (no multiplayer), run this command:

node index.js --backup <insert uuid here> --device <number> --quests

Your user data will be backed up to a file called user_data.json. Make sure to have this handy for a potential private server in the future.

How Does the API Work?

There are 2 main endpoints involved in the API: api-s.kingdomhearts.com and psg.sqex-bridge.jp/native/session. Upon startup, KHUx communicates using an HTTPS REST API and JSON payloads to the KH api to obtain some status and session information. Most of these payloads are compressed using gzip. Then KHUx obtains a sharedSecurityKey and more session cookies from sqex after sending its session info.

This sharedSecurityKey is then used to encrypt/decrypt the JSON payload using AES-256 CBC mode. The encryption process is as shown:

Raw JSON --(base64 encode)--> --(AES encrypt)--> -->(base64 encode)--> final payload

Decrypting the payload is the reverse:

received payload --(base64 decode)--> --(AES decrypt)--> --(base64 decode)--> final payload

What Does the Tool Do?

At the moment, the tool will automatically decode the traffic and display it in console in human-readable form. There is also support for easy modification to the JSON payload going to/from KHUx. The tool will repackage the payload in the form that KHUx understands.

How To Setup