Cocos2d JSC

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JSC, JS

• Format Type : Compiled Script
  
• Endian Order : Little Endian
  
• Signature : None
  

Format Specifications

x bytes - file data  // it may be encrypted or compressed

Notes and Comments

• This file format occurs in games made using Cocos2d-x framework.
• JSC is a compiled JavaScript file used by SpiderMonkey Engine.
• JSC may be compressed with GZIP / ZIP and encrypted with XXTEA.

Games

List of games using this file format:

Game Title	Platform	Extension	Type	Encryption Key
Animal Restaurant	Android	*.JSC	XXTEA + GZIP	431FEWJOTe-gecTW
Aries Peg Solitaire	Android	*.JSC	XXTEA + ZIP	097c5192-4e62-4f
Brutal Street 2	Android	*.JSC	Bytecode (version 33)	None
Cat Rescue: Sea Escape	Android	*.JSC	XXTEA + GZIP	863c18da-7a0f-41
Choang Club - Game bai dang cap	Android	*.JSC	Bytecode (version 33)	None
DesignVille: Merge & Design	Android	*.JS	Uncompiled JavaScript	None
Happy Animal Hospital	Android	*.JSC	XXTEA + GZIP	dwyygp
Jimi-Kare My Quiet Boyfriend	Android	*.JSC	Bytecode (version 33)	None
KungFu Hospital	Android	*.JSC	XXTEA + GZIP	yiguangp
LifeSimulator - Chinese Life	Android	*.JSC	XXTEA + GZIP	e07a4d47-b82e-4f
Minimal Dungeon RPG	Android	*.JSC	XXTEA + GZIP	0144fe29-6a3f-49
One Piece (chinese game)	Android	*.JSC	XXTEA + GZIP	b81a1dd7-625d-43
Resortopia	Android	*.JSC	XXTEA + GZIP	65fccf9c-1473-4d
Santa Bouncy Lights	Android	*.JSC	XXTEA + GZIP	7820d0b2-c505-4b
Spiral Warrior	Android	*.JSC	XXTEA Only	f86f2406-6ef3-45
Top War: Battle Game	Android	*.JSC	XXTEA + GZIP	221640c9-d86d-43

Tutorial - How to get XXTEA keys

Method 1:

• Open file \lib\armeabi-v7a\libcocos2djs.so in hex editor and search for "jsb-adapter" or "applicationDidFinishLaunching". Key should be stored right before or after those strings.

Method 2:

• Install and run frida server on your device
• Download this script cocos2d_xxtea_script.js
• Run the script with the command "frida -U --no-pause -l cocos2d_xxtea_script.js -f <game_package_name>

Method 3:

• Download and install IDA 7
• Seaach for function "xxtea_decrypt"
• Analyse the function's code to see how the key is stored/generated.

QuickBMS Script

• One Piece JSC script

Compatible Programs

• cocos2d-x + cocos2d-x-samples
• cocos2d-jsc-decompiler
• cocos-jsc-endecryptor
• cocos2d/Spidermonkey
• Frida Server + cocos2d_xxtea_script.js
• JSC decrypt tool (by Mika Cybertron)
• JSC-PyDecrypt-Tool
• JSC Tool
• jsc-decompile-mozjs-34
• Winrar / 7-zip (only for GZIP decompression)

See Also

• How to find decrypt key for cocos2djs?
• How to find decryption key for cocos2djs
• How to decompile JSC files (chinese tutorial)
• Road to decompile JSC (chinese tutorial)

Gallery

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  JSC Tool by Mika Cybertron