/*
 * Dictionary Augmentaion (2021)
 * - Justin Parrott (2600 Magazine - Volume 38, No. 4)
 *
 *   Augment your dictionary attack by altering the case and
 *   substituting numbers for letters and letters for numbers.
 *   Also by shuffling each word.  We're going to iterate 
 *   through all of our possibilities for each word in our
 *   dictionary.
 *
 *   i.e.:
 *   	* In l33tsp3ak, "elite" becomes "eli73" et al.
 *   	* When shuffling, "elite" becomes "tleie" et al.
 *
 *   Dictionaries:
 *   	A dictionary for password cracking is just a list of words.
 *   	Each word is on its own line and no whitespace follows the word.
 *
 *   UNIX Use:
 *   step 0) source code in 'leet.c', wordlist in 'words'
 *   step 1) cc -o leet -std=c99 leet.c   # compile it
 *   step 2) ln leet shuffle                # link shuffle
 *   step 3) echo test | ./leet             # test l337sp34k
 *   step 4) echo test | ./shuffle          # test shuffling
 *   step 5) echo test | ./leet | ./shuffle # test both together
 *   step 6) ./leet < words                 # augment your dictionary
 *       or) ./shuffle < words
 *   step 7) pipe step 7 to stdin on your password cracker
 *
 *   Windows Notes:
 *   On step 1) I use clang to compile on Windows 10 (add the -w option)
 *
 *   i.e. clang -o leet.exe -std=c99 -w leet.c
 *   on step 2) Use: mklink shuffle.exe leet.exe
 *   on step 3,4,5,6) you don't need the "./"
 *   on step 6 Use: type words | leet
 *              or: type words | shuffle
 */

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

#define LINELEN 64

#ifdef _WIN32
#define DIR_CHAR '\\'
#else
#define DIR_CHAR '/'
#endif

#ifndef min
#define min(a,b) ((a) < (b) ? (a) : (b))
#endif

/* If we find one character in the string, iterate the whole group.
 * i.e. We find '7' in the string 'tT7,' so we iterate tT7.
 * This is how we group our characters.
 */

char *groups[] = {
  "aA4@", "bB86&", "cC", "dD", "eE3",
  "fF", "gG", "hH#", "iI1lL!", "jJ",
  "kK", "mM", "nN", "oO0", "pP", "qQ",
  "rR9", "sSzZ52$", "tT7", "uUvV",
  "wW", "xX", "yY", NULL
};

/* lookup a character group for l33tsp34k translation */

char *lookupg(char c)
{
  char *s, **g = groups;

  while (*g) {
    for (s = *g; *s; s++)
      if (*s == c)
        return *g;
    g++;
  }
  return NULL;
}

/* translate a word to l33tsp34k */
void leet(char *s, const char *word)
{
  char *grp, tbuf[LINELEN];

  if (*s) {
    if (grp = lookupg(*s)) {
      while (*grp) {
        sprintf(tbuf, "%s%c", word, *grp++);
        leet(s + 1, tbuf);
      }
    } else {
      sprintf(tbuf, "%s%c", word, *s);
      leet(s + 1, tbuf);
    }
  } else
    puts(word);
}

/* shuffle characters of a word */
void shuffle(char *s, size_t slen, const char *word)
{
  char c, cpy[LINELEN], tbuf[LINELEN];
  bool mod = false;

  memcpy(cpy, s, slen + 1);

  for (size_t i = 0; i < slen; i++) {
    if (c = cpy[i]) {
      cpy[i] = '\0';
      sprintf(tbuf, "%s%c", word, c);
      shuffle(cpy, slen, tbuf);
      cpy[i] = c;
      mod = true;
    }
  }
  if (!mod)
    puts(word);
}

int main(int argc, char *argv[])
{
  bool shfl = false;
  char line[LINELEN], *p = strchr(argv[0], DIR_CHAR);

  /* the program name tells us what to do */
  if (p)
    p++;
  else
    p = argv[0];
  /* compare against "shuffle", excluding ".exe", for Windows */
  if (!strncmp(p, "shuffle", min(strlen(p), 7)))
    shfl = true;

  while (fgets(line, sizeof line, stdin)) {
    line[strcspn(line, "\n")] = '\0';
    if (shfl)
      shuffle(line, strlen(line), "");
    else
      leet(line, "");
  }
  return 0;
}