crack.c

/**
* crack.c
*
* Alisha Ukani
*
* Cracks DES-encrypted passwords
*/
 
#define _XOPEN_SOURCE
#include <unistd.h>
#include <cs50.h>
#include <stdio.h>
#include <string.h>
 
bool testPassword(string encrypted, string password, string salt);
 
int main(int argc, string argv[]) {
    // make sure there are only 2 command line arguments
    if (argc != 2) {
        return 1;
    }
    
    // encrypted is the actual given password
    string encrypted = argv[1];
    
    // generate salt
    string salt = {(char)(encrypted[0]), (char)(encrypted[1])};
            
    /* check passwords in dictionary
    FILE *dictionary = fopen("/usr/share/dict/words", "r");
    string line = "";
  
    while (fscanf(dictionary, "%s", line) != EOF) {
        if (testPassword(encrypted, line, salt)) {
            return 0;
        }
    }
    fclose(dictionary);*/
            
    // for loops find all possible passwords
    for (int a = 32; a <= 126; a++) {
        for (int b = 32; b <= 126; b++) {
            for (int c = 32; c <= 126; c++) {
                for (int d = 32; d <= 126; d++) {
                    for (int e = 32; e <= 126; e++) {
                        for (int f = 32; f <= 126; f++) {
                            for (int g = 32; g <= 126; g++) {
                                for (int h = 32; h <= 126; h++) {
                                            
                                    char password_arr[] = {a, b, c, d, e, f, g, h};
                                    string password = password_arr;
                                            
                                    if (testPassword(encrypted, password, salt)) {
                                        return 0;
                                    }
                                    
                                    // check password with whitespace removed
                                
                               }
                            }
                        }
                    }
                }
            }
        }
    }
}
        
// returns true if "password" is the correct password
bool testPassword(string encrypted, string password, string salt) {
    if (crypt(password, salt) == encrypted) {
        printf("%s\n", password);
        return true;
    }
    return false;
}