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I have done a small code in which with a wordlist (out68.lst) I get the passwords from the hashes in the file 'shadow3'.

import crypt

import string

import itertools

import datetime



dir = "shadow3"                          #File that contains hashes and users

file = open(dir, 'r').readlines()



username = 

hashed = 

k=0





for x in file:

    usr, hshd, wtf, iss, this, thing, here, doing, example = x.split(':')

    username.append(usr)

    hashed.append(hshd)

#Loop in order to split the data in the file and store it in username and hashed



grupo1=open('out68.lst','r').readlines()

long=len(grupo1)

print(long)

for y in grupo1:    #Loop in order to go through all the possible words available

  c = 0

  y=y.rstrip('n')

  y=y.capitalize()

  k = k+1

  if k==(long//100):

    print('1%')

  if k==(long//10):

    print('10%')

  if k==(long//5):

    print('20%')

  if k==(3*long//10):

    print('30%')

  if k==(4*long//10):     #Just to check the progress

    print('40%')

  if k==(5*long//10):

    print('50%')

  if k==(6*long//10):

    print('60%')

  if k==(7*long//10):

    print('70%')

  if k==(8*long//10):

    print('80%')

  if k==(9*long//10):

    print('90%')





  for x in hashed:

      rehashed = crypt.crypt(y, x) #Hash verification f(passwor+hash)=hash?

      if rehashed == x:

          print('La contraseña del usuario ' + username[c] + ' es ' + y)

      c = c + 1

It does work but depending on the size of the files, it can last now from 30 minutes to 6 hours. So I am asking if there is any way to improve the performance, by paralelization, or GPU processing (but I have no idea about this).

Some suggestions:

• Run the code through at least one linter such as flake8 or pycodestyle to produce more idiomatic code.


• Don't read all the lines into a variable before starting processing - this will slow things down and use much more memory than necessary for large files. Instead you can use for line in file.readlines().


• You are doing ten calculations in order to run a single print statement. Either get rid of them or do something simpler like print("{}/{} complete".format(k, long)).


• If you know y has exactly one newline at the end you can do y[:-1] instead of y.rstrip('n').


• Capitalizing each word is expensive. Avoid it if at all possible.


• If you don't need a bunch of the fields in an input file add a limit to your split() and mark the last stuff as discarded by using the _ variable. For example: usr, hshd, _ = x.split(':', 3)
  


• Rather than keeping track of k manually you can just do for k, y in enumerate(grupo1).


• Rather than having a list of usernames and a list of their hashed passwords, a Dict[str, str] of username to hash should be easier to keep track of.

You should make sure you close files you open. This can be easily achieved using the with keyword:

file_name = "shadow3"

with open(file_name) as file:

    usernames, hashed_passwords = , 

    for line in file:

        username, hashed_password, *_ = line.split(':')

        usernames.append(username)

        hashed_passwords.append(hashed_password)

Calling a file dir is just setting yourself up for trouble later. I also used the advanced tuple assignment by using * to assign the rest of the line to the unused variable _ (a customary name for unused variables).

Note that open opens a file in read-only mode by default, so 'r' is implicitly used.

Whenever you want to iterate over an iterable but also need a counter, use enumerate and whenever you want to iterate over two iterables in tandem, use zip:

with open('out68.lst') as group:

    length = len(group)

    for k, password in enumerate(group):

        password = password.rstrip('n').capitalize()



        if k == length // 100 or k % (length // 10) == 0:

            print(f"{k / length:.%}")

        for username, hashed_password in zip(usernames, hashed_passwords):

            if crypt.crypt(password, hashed_password) == hashed_password:

                print(f'La contraseña del usuario {username} es {password}')

Here I also used modular arithmetic to cut down your special cases for ten percent increments, used the new f-string formatting.

You might want to add some functionality where you save username password pairs if you have found some and remove them from the usernames and hashed_passwords lists so you don't keep on checking them once you found the password. To do this efficiently it might be necessary to change your data format to {username: hashed_password} and {username: password} for the yet to find and already found usernames.

file_name = "shadow3"

users = {}

with open(file_name) as file:

    for line in file:

        username, hashed_password, *_ = line.split(':')

        users[username] = hashed_password



cracked_users = {}

with open('out68.lst') as group:

    length = len(group)

    for k, password in enumerate(group):

        password = password.rstrip('n').capitalize()

        if k == length // 100 or k % (length // 10) == 0:

            print(f"{k / length:.%}")

        if not users:

             print("Cracked all passwords")

             break

        for username, hashed_password in users.items():

            if crypt.crypt(password, hashed_password) == hashed_password:

                print(f'La contraseña del usuario {username} es {password}')

                cracked_users[username] = password

                del users[username]

In general, don't be afraid of giving your variables clear names. If it is a username, call it username, not usr. If it is a hashed password, call it hashed_password, not hshd.