crack.c

#include <cs50.h>
#include <stdio.h>
#include <string.h>
#include <unistd.h>
#include <crypt.h>

#define _XOPEN_SOURCE
#define MAX_SIZE 5

bool cracked = false;

void crack1(string hash, string salt, char pass[]);
void crack2(string hash, string salt, char pass[]);
void crack3(string hash, string salt, char pass[]);
void crack4(string hash, string salt, char pass[]);
char skip_non_alpha(char c);
void print_pass(char pass[]);

int main (int argc, string argv[]) {
    if (argc != 2) {
        printf ("Usage: ./crack hash\n");
        return 1;
    }
    string hash = argv[1], salt = "50";
    char pass[MAX_SIZE];
    crack1(hash, salt, pass);
    if (cracked == true)
        return 0;
    crack2(hash, salt, pass);
    if (cracked == true)
        return 0;
    crack3(hash, salt, pass);
    if (cracked == true)
        return 0;
    crack4(hash, salt, pass);
}

char skip_non_alpha(char c) {
    if (c == 'Z' + 1)
        c = 'a';
    return c;
}

void print_pass(char pass[]) {
    for (int i = 0; i < MAX_SIZE; i++) 
        printf ("%c", pass[i]);
    printf ("\n");
}

void crack1(string hash, string salt, char pass[]) {
    for (char c = 'A'; c <= 'z'; c++) {
        c = skip_non_alpha(c);
        pass[0] = c;
        string test = crypt(pass, salt);
        if (strcmp(test, hash) == 0) {
            cracked = true;
            print_pass(pass);
            break;
        }
        if (cracked == true)
            break;
    }
}

void crack2(string hash, string salt, char pass[]) {
    for (char c = 'A'; c <= 'z'; c++) {
        c = skip_non_alpha(c);
        pass[0] = c;
        for (char c1 = 'A'; c1 <= 'z'; c1++) {
            c1 = skip_non_alpha(c1);
            pass[1] = c1;
            string test = crypt(pass, salt);
            if (strcmp(test, hash) == 0) {
                cracked = true;
                print_pass(pass);
                break;
            }
        }
        if (cracked == true)
            break;
    }
}

void crack3(string hash, string salt, char pass[]) {
    for (char c = 'A'; c <= 'z'; c++) {
        c = skip_non_alpha(c);
        pass[0] = c;
        for (char c1 = 'A'; c1 <= 'z'; c1++) {
            c1 = skip_non_alpha(c1);
            pass[1] = c1;
            for (char c2 = 'A'; c2 <= 'z'; c2++) {
                c2 = skip_non_alpha(c2);
                pass[2] = c2;
                string test = crypt(pass, salt);
                if (strcmp(test, hash) == 0) {
                    cracked = true;
                    print_pass(pass);
                    break;
                }
            }
        }
        if (cracked == true)
            break;
    }
}

void crack4(string hash, string salt, char pass[]) {
    for (char c = 'A'; c <= 'z'; c++) {
        c = skip_non_alpha(c);
        pass[0] = c;
        for (char c1 = 'A'; c1 <= 'z'; c1++) {
            c1 = skip_non_alpha(c1);
            pass[1] = c1;
            for (char c2 = 'A'; c2 <= 'z'; c2++) {
                c2 = skip_non_alpha(c2);
                pass[2] = c2;
                for (char c3 = 'A'; c3 <= 'z'; c3++) {
                    c3 = skip_non_alpha(c3);
                    pass[3] = c3;
                    string test = crypt(pass, salt);
                    if (strcmp(test, hash) == 0) {
                        cracked = true;
                        print_pass(pass);
                        break;
                    }
                }
            }
        }
        if (cracked == true)
            break;
    }
}