#define _XOPEN_SOURCE
#include <unistd.h>
#include <stdio.h>
#include <string.h>

#define MAX 72

int main(void)
{
	const char *setting = "$2a$04$abcdefghijklmnopqrstuu";
	char pw[MAX + 1], saved[61], *hash;
	unsigned int i, j, n;
	unsigned int total, bad;

	total = bad = 0;
	for (n = 0; n < MAX; n++) {
		pw[n] = 'a';
		pw[n + 1] = 0;

		for (i = 0; i <= n; i++) {
			int reported = 0;

			pw[i] = 0xa3;
			memcpy(saved, crypt(pw, setting), sizeof(saved));

			for (j = (i < 3) ? 0 : (i - 3); j < i; j++) {
				pw[j] = 'b';
				hash = crypt(pw, setting);
				pw[j] = 'a';

				if (memcmp(hash, saved, sizeof(saved)))
					continue;

				if (!reported)
					printf(
"length %u, 8-bit @ %u overwrites @", n + 1, i + 1);
				printf(" %u", j + 1);
				reported = 1;
			}

			pw[i] = 'a';

			total++;
			if (reported) {
				putchar('\n');
				bad++;
			}
		}

		if (n != (19 - 1) && n != (MAX - 1))
			continue;

		printf("\nBad / total {length, position}s: %u / %u = %.2f\n\n",
		    bad, total, (double)bad / total);
	}

	return 0;
}