The XOR function used in Z3Ex.dll

rs3Unscramble.c

void rs3Unscramble( char *srcBuffer, DWORD srcSize, DWORD xorkey )
{
	// Unscramble the 32-bit blocks

	DWORD dBlocks = srcSize >> 2;
	while( dBlocks )
	{
		DWORD tmp;
		tmp = *(DWORD *)srcBuffer; // read 32-bit value
		
		xorkey += tmp;
		tmp ^= xorkey;
		
		*(DWORD *)srcBuffer = tmp; // write 32-bit value
		srcBuffer += 4;
		--dBlocks;
	}
	
	// Unscramble the remaining data (1-3 bytes)

	BYTE bAlign = (BYTE)(srcSize & 3);
	if( bAlign )
	{
		DWORD lastBlock;
		int i;

		lastBlock = 0;
		i = 0;

		// read remaining 8/16/24-bit value
		while( i < bAlign )
		{
			DWORD tmp;
			tmp = *(BYTE *)(srcBuffer + i);
			tmp <<= i << 3;
			lastBlock |= tmp;

			++i;
		}

		xorkey += lastBlock;
		lastBlock ^= xorkey;
		
		// write remaining 8/16/24-bit value
		i = 0;
		while( i < bAlign )
		{
			*(BYTE *)(srcBuffer + i) = (BYTE)lastBlock;
			lastBlock >>= 8;

			++i;
		}
	}
}