#include <stdio.h>
#include <stdlib.h>
#define PROG "skey"

static int size(FILE *fp)
{
        int i;

        fseek(fp, 0, SEEK_END);
        i = ftell(fp);
        rewind(fp);
        return i;
}

int main(int argc, char *argv[])
{
	int i, j;
	unsigned char *buf;
	FILE *fp;

	argv[0] = argv[0][0] == '\0' ? PROG : argv[0];

	if (argc < 3) {
		fprintf(stderr, "usage: %s key file\n", argv[0]);
		return EXIT_FAILURE;
	}

	if ((fp = fopen(argv[2], "rb")) == NULL) {
		fprintf(stderr, "%s: couldn't open file\n",
                                argv[0]);
		return EXIT_FAILURE;
	}

	if ((buf = malloc(size(fp)+1)) == NULL) {
		fprintf(stderr, "%s: malloc failed\n", argv[0]);
		return EXIT_FAILURE;
	}

	fread(buf, 1, size(fp), fp);
	for (i = j = 0; i < size(fp); i++, j++) {
		j *= argv[1][j] != '\0';
		putchar(buf[i] ^ argv[1][j]);
	}
	
	return 0;
}