mask

mask.c

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

#define MASK1 0b01110101
#define MASK2 0b11101011

int main(int argc, char **argv) {
  int i;
  char s[64], t[64], u[64];

  if (argc == 1) {
    printf("Usage: ./mask [FLAG]\n");
    return 0;
  }

  strcpy(s, argv[1]);
  int len = strlen(s);

  printf("Putting on masks...\n");
  for (i = 0; i < len; i++) {
    t[i] = s[i] & MASK1;
    u[i] = s[i] & MASK2;
  }

  t[len] = '\0';
  u[len] = '\0';

  printf("%s\n", t);
  printf("%s\n", u);

  if (!strcmp(t, "atd4`qdedtUpetepqeUdaaeUeaqau") && !strcmp(u, "c`b bk`kj`KbababcaKbacaKiacki")) {
    printf("Correct! Submit your FLAG.\n");
  } else {
    printf("Wrong FLAG. Try again.\n");
  }

  return 0;
}