お.c

#include <stdio.h>

#define ID_LEN 12

int main() {

	char id[ID_LEN] = {
		0x30, 0x31, 0x30, 0x30, 
		0x30, 0x37, 0x33, 0x34, 
		0x45, 0x30, 0x44, 0x32
	};

	unsigned int check;
	char check_c[3] = {'\0'};

	sprintf(check_c, "%c%c", id[10], id[11]);
	sscanf(check_c, "%x", &check);

	unsigned int sum = 0;

	for (int i = 0; i < ID_LEN - 2; i += 2){

		unsigned int sum_t = 0;
		char sum_c[3] = {'\0'};

		sprintf(sum_c, "%c%c", id[i], id[i + 1]);
		sscanf(sum_c, "%x", &sum_t);

		sum ^= sum_t;
	
	}

	if (check == sum) {
		printf("OK\n");
	} else {
		printf("NG\n");
	}

}