Password Cracker Program

Question

I was assigned a code by my professor and was told to improve the performance of it. The code is very raw, but I was thinking that adding a brute force code would improve the return rate of the program and come about the password at a faster rate. I just don't know how to go about implementing such a code.
The code is below.
final String GOOD_PASSWORD = "goodmorning";
          String enteredPassword = "";
          boolean passwordOk = false;
          long numOfTrials = 0;
          Random generator = new Random ( );
          int len;
          final int PASSWORD_LEN_LIMIT = 30;
          int charCode;
          boolean charOk;
          do
                    enteredPassword = "";
                    //guess the number of chars in the password 1 - 30 chars
                    len = generator.nextInt (PASSWORD_LEN_LIMIT) + 1;
                    for (int i = 0; i < len; i++)
                         //creating a number that can be used as a char in a password
                         //digits: 48 - 57
                         //upper case: 65 - 90
                         //lower case: 97 - 122
                         charOk = false;
                         do
                              charCode = generator.nextInt (75) + 48;
                              if (((charCode <= 57) && (charCode >= 48)) ||
                                   ((charCode <= 90) && (charCode >= 65)) ||
                                   ((charCode <= 122) && (charCode >= 97)))
                                   charOk = true;
                         } while (!charOk);
                         enteredPassword = enteredPassword + (char) charCode;
                    System.out.print (enteredPassword + "///");
                    JOptionPane.showMessageDialog (null, enteredPassword);
                    if (enteredPassword.equals (GOOD_PASSWORD))
                         passwordOk = true;
                    else
                         numOfTrials++;
               } while (!passwordOk);
               JOptionPane.showMessageDialog (null, "password cracked after " + numOfTrials + " trials");
               System.exit (0);
}What the program is set to do is have the computer guess the characters of the password and then have it randomly generate letters and digits in an attempt to guess what the password might be. I tried making the good password less letters (would be like having a website require a smaller amount of maximum characters in a password) and still have to go through an immense amount of trials to get it to work. Do you guys have any ideas on how I might be able to get the password to be "cracked" in a fewer amount of tries? Possibly a brute force code or something, and if so how would that be implemented.

Answer 1

No I wasn't trying to get this done for me. I was suggested to use a brute force code because the way the professor gave it was just insane (randomly attempt using digits, lc letters and uc letters until arriving on the correct password). Of course, using brute force method would be equally painful.
This is what I have so farimport javax.swing.JOptionPane;
import java.*;
public class LogInX
     char[] canUse = {'0','1','2','3','4','5','6','7','8','9',
                         'a','b','c','d','e','f','g','h','i','j','k',
                         'l','m','n','o','p','q','r','s','t','u','v','w','x','y','z'
     public static void main (String[ ] args)
          final String GOOD_PASSWORD = "goodmorning";
          String enteredPassword = "";
          boolean passwordOk = false;
          long numOfTrials = 0;
          int maxlen=10;
          int charCode;
                    enteredPassword = "";
                    for (int i = 0; i < len; i++)
                         do
                              brute b = new brute();
                         } while (enteredPassword = false);
                              int k = 0;
                              while (k < canUse.length)
                                        nextString(new Character(canUse[k]).toString());
                                        k++;
                                   int i = 0;
                                   System.out.println(s);
                                   while (i< canUse.length)
                                        System.out.println(s + new Character(canUse).toString());
                                        if (new String(s + new Character(canUse[i]).toString()).length() <= maxlen) {nextString(s + new Character(canUse[i]).toString());
                                        i++;
                         enteredPassword = enteredPassword + (s + new Character(canUse[i]).toString()) ;
                    System.out.print (enteredPassword + "///");
                    JOptionPane.showMessageDialog (null, enteredPassword);
                    if (enteredPassword.equals (GOOD_PASSWORD))
                         passwordOk = true;
                    else
                         numOfTrials++;
               } while (!passwordOk);
               JOptionPane.showMessageDialog (null, "password cracked after " + numOfTrials + " trials");
               System.exit (0); }
And even in this, I have compiled one error that I cannot find, and beyond that I am not sure if it would do what I am looking for it to do. I have a standalone brute force code that does what I was thinking (cycle through letters and digits) and I tried to piece in the bulk of that code into what I originally posted. Does anyone have any advice on fixing up the code above, or how I might be able to go about it differently? Thanks for the feedback.
Edited by: xisstar on Jun 9, 2009 3:51 PM