gregdmeyer/passgen

Password generator with many options for password type, including use of random words

Generate random passwords.

Requires: Python 3, pycrypto

Includes ability to use words in the style of xkcd: Password Strength.

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Options (= default):

When calling on the command line as python3 passwordGen.py, give options as -option value. Otherwise in Python 3 you can call make_pass(option=value).

• min_entropy = 30: The minimum entropy of the generated password. Entropy is defined as $\log_2$ of the total number of "similar" passwords. For a sense of scale, entropy of 30 or 40 is probably reasonable for general use. Entropy of >60 or so, you are pretty safe from even a powerful offline brute force attack.
• min_length = 8: The minimum length in characters of the password.
• max_length = 20: The maximum length in characters.
• join_str = '': The string used to join elements of the password. For example, join_str='' -> thepassword, join_str='_' -> the_password
• pool = 'chars': The pool from which to draw password elements (the set of things the password is generated from). Possibilities are:
  • chars: The set of all standard non-whitespace characters, i.e. punctuation, upper and lowercase letters, and digits. Note that if you are required to have a letter, number, and punctuation in your password, you might have to generate a few passwords before getting one that satisfies all the requirements.
  • alphanumeric: Just letters and numbers (no punctuation). Useful because they are very quick to type--and can still have a safe amount of entropy with a slightly longer password.
  • lowercase: lowercase letters only.
  • words: These passwords are designed to be easy to remember. Based off of the idea presented by Randall Munroe in xkcd: Password Strength. By default, loads a list of words from /usr/share/dict/words, and make password by choosing random words from that list. If you pass this option, you can also pass -word_file <path> to give your own custom word list. I think using the set of 1000 most common English words is nice, some good lists can be found here.
  • Finally, if calling in Python, you can simply pass a list of strings to pool and it will use that directly.
• verbose: By default True when called from the command line, by default False when called in Python. Whether to print out the password and information about its length, entropy, etc.
• filter_fn = None: Only can be used when calling in Python (not from command line). This option gives the ability to apply some filter to the list. Should be a function that returns True or False when passed a string. For example, if you only want words shorter than 5 characters, do make_pass(pool='words',filter_fn=lambda x: len(x) < 6).
• mod_fn: Also can only be used when calling in Python. This is a function that is applied to all elements before they are used. Default is none unless pool='words'. For example:
  • If you want all words in your password to be lowercase, do: make_pass(pool='words',mod_fn=lambda x: x.lower())
  • Or maybe make first letters uppercase: make_pass(pool='words',mod_fn=lambda x: x[0].upper() + x[1:].lower()). This is the default if pool='words'.

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Enjoy!