/*
 *  character-set based brute-forcing algorithm
 *  (c) 2004 by mimayin@aciiid.ath.cx
 *
 *  usage: ./crunch <from-len> <to-len> [charset] [-t [FIXED]@@@@] [-s startblock]
 *
 *  e.g: ./crunch 3 7 abcdef
 *
 *  This example will compute all passwords between 3 and 7 chars
 *  using 'abcdef' as the character set and dump it to stdout.
 *
 *  Options:
 *
 *  -t [FIXED]@@@@  :  allows you to specify a pattern, eg: @@god@@@@ 
 *                     where the only the @'s will change
 *
 *  -s              :  allows you to specify the starting string, eg: 03god22fs
 *
 *
 *  This code can be easily adapted for use in brute-force attacks
 *  against network services or cryptography.
 *
 *  Compiles on: linux, ms visual c++, freebsd
 *
 */

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

#define TRUE  1
#define FALSE  0

char def_charset[] = "abcdefghijklmnopqrstuvwxyz";

unsigned int inc[128];

int finished(char *block, char *charset, char *templ)
{
  unsigned int i;

  if(templ[0]==0)
  {
    for(i=0;i<strlen(block);i++)
      if(inc[i] < strlen(charset)-1)  return FALSE;
  }
  else
  {
    for(i=0;i<strlen(block);i++)
      if(templ[i]=='@' && (inc[i] < strlen(charset)-1)) return FALSE;
  }

  return TRUE;
}

void increment(char *block, int len, char *charset, char *templ)
{
  int i;

  for(i=strlen(block)-1;i>-1;i--)
  {
    if(templ[0]==0 || templ[i]=='@')
    {
      if(inc[i] < strlen(charset)-1)
      {
        inc[i]++;
        block[i] = charset[inc[i]];
        i=-1;
      }
      else
      {
        block[i] = charset[0];
        inc[i] = 0;
      }
    }
    else
    {
    }
  }
}

void chunk(int start, int end, char *charset, char *templ, char *startblock)
{
  int i,j,k,t;
  char block[128];

  if(end-start <0) return;

  if(templ[0]==0) t=0;
  else    t=1;

  for(i=start;i<=end;i++)
  {
    memset(block,0,sizeof(block));

    for(j=0;j<i;j++)
    {
      if(startblock[0]==0)
      {
        if(t==0)
        {
          block[j] = charset[0];
          inc[j] = 0;
        }
        else
        {
          if(templ[j]=='@')
          {
            block[j] = charset[0];
            inc[j] = 0;
          }
          else      block[j] = templ[j];
        }
      }
      else
      {
        block[j] = startblock[j];

        for(k=0;k<strlen(charset);k++)
          if(block[j]==charset[k]) inc[j] = k;
      }
    }

    printf("%s\n",block);
    while(!finished(block,charset,templ))
    {
      increment(block,i,charset,templ);
      printf("%s\n",block);
    }
  }
}

int main(int argc, char *argv[])
{
  int i,j,flag,min,max;
  char charset[256];
  char templ[256];
  char startblock[256];

  if(argc<3)
  {
    printf("usage: %s <from-len> <to-len> [charset] [-t [FIXED]@@@@] [-s startblock]\n",argv[0]);
    return 0;
  }

        memset(charset,0,sizeof(charset));
        memset(templ,0,sizeof(templ));
        memset(startblock,0,sizeof(startblock));

  /* remove duplicate characters from charset */
  if(argc>3)
  {
    for(i=0;i<strlen(argv[3]);i++)
    {
      flag = 0;
      for(j=0;j<strlen(charset);j++)
        if(argv[3][i] == charset[j]) flag = 1;

      if(flag==0) strncat(charset,&argv[3][i],1);
    }
  }
  else    strncpy(charset,def_charset,strlen(def_charset));

  min = atoi(argv[1]);
  max = atoi(argv[2]);

  for(i=1;i<argc-1;i++)
  {
    if(strncmp(argv[i],"-t",2)==0)
    {
      strncpy(templ,argv[i+1],strlen(argv[i+1]));
    }

    if(strncmp(argv[i],"-s",2)==0)
    {
      if(strlen(argv[i+1]) >min)
      {
        printf("Warning: starting length increased to %d.\n",strlen(argv[i+1]));
        min = strlen(argv[i+1]);
      }
      if(strlen(argv[i+1]) <min)
      {
        printf("Warning: minimum length decreased to %d.\n",strlen(argv[i+1]));
        min = strlen(argv[i+1]);
      }

      strncpy(startblock,argv[i+1],strlen(argv[i+1]));
    }
  }

        chunk(min,max,charset,templ,startblock);

        return 0;
}