Small C Program to unpack Level 2 Protection of Jar2exe

Jar2ExeUnpack_Level2.c

/*
================================================|
Jar2Exe level 2 Unpacker (Hide Class protection)|
Created by Levis Nickaster						|
http://ltops9.wordpress.com						|
================================================|
*/

#include <stdio.h>
#include <stdlib.h>
#include <windows.h>
#define ENCRYPTED_RES_ID 128 //ID for encrypted JAR file in RCDATA

int main(int argc, char const *argv[])
{
	HMODULE hExe;
	char* fileName = (char*)argv[1];
	hExe = LoadLibrary(TEXT(fileName)); //Load exe file which contains encrypted resource
	if(hExe)
	{
		//Find encrypted resource
		HRSRC hRes = FindResource(hExe, MAKEINTRESOURCE(ENCRYPTED_RES_ID),RT_RCDATA);
		if(hRes)
		{
			//Load Resource and get Pointer to it
			HGLOBAL ResData = LoadResource(hExe,hRes); 
			void* encryptedJAR = LockResource(ResData);
			//Get Resource size
			int len = SizeofResource(hExe,hRes);
			printf("Found embedded Resource with length %d bytes! Unpacking...\n",len);
			//allocate memory to store decrypted Java
			char* decryptedJAR = (char *)malloc(len+1);
			if(decryptedJAR)
			{
				char* pChar= (char *)encryptedJAR;
				//decrypt byte by byte and save it to memory region
				for (int i = 0; i < len; ++i)
				{
					decryptedJAR[i]=(4*pChar[i])|(pChar[i]>>6)&3;
				}
				//Write out Decrypted JAR file and free memory
				strcat(fileName,"-decrypted.jar");
				FILE* outputFile = fopen(fileName, "wb");
				fwrite(decryptedJAR,len,1,outputFile);
				printf("File saved to : %s", fileName);
				fclose(outputFile);
				free(decryptedJAR);
				FreeLibrary(hExe);
			}
			//if cannot allocate memory
			else{printf("ERROR: Could not allocate enough memory!");}
		}
		//if cannot find encrypted resource (file not packed by jar2exe)
		else{printf("ERROR: Encrypted Resource not found! Maybe it's not packed by jar2exe");}
	}
	//if file not found
	else{printf("ERROR: File not found!");}
	return 0;
}