Decode Type 7 string

type7.c

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#define	TYPE7_LUT_SZ	53
const unsigned char type7_lut[] = "dsfd;kfoA,.iyewrkldJKDHSUBsgvca69834ncxv9873254k;fg87";

void deobfuscate( const char* in, char* out)
{
    int in_sz = strlen( in)/2;
    unsigned char val;
    char offset_str[3] = { 0, 0, 0};
    
    // Read LUT offset (stored in decimal form in 2 first bytes)
    memcpy( offset_str, in, 2);
    int offset = atoi( offset_str);
    
    for( int i=1; i<in_sz; ++i)
    {
        sscanf( in+(i*2), "%2hhx", &val);	// Read and decode hex byte
    	out[i-1] = val ^ type7_lut[offset];	// XOR read byte and LUT byte
    	
    	if( ++offset >= TYPE7_LUT_SZ) 		// Increment LUT offset
    		offset = 0;
    }
}

int main( int argc, char** argv)
{
	if( argc != 2 )
	{
		printf( "Usage: %s type7_secret\n", argv[0] );
		return 1;
	}
	
	// Allocate result string
	int clear_len = strlen( argv[1]) / 2;
	char *result = (char*) malloc( clear_len);
	memset( result, clear_len, 0);
	
	deobfuscate( argv[1], result);
	
	printf( "Decoded password: %s\n", result);
	free(result);
	
	return 0;
}