Python Password Generator - pypass-generator

Generates passwords and passphrases

You can pip install pypass-generator

Current State: generates passphrases using the pypass.passphrase.PassphraseGenerator namespace from any word generator. Includes a Diceware word generator in pypass.generator.Diceware

Randomization is done in a secure fashion using random.SystemRandom, and it's easy to write your own generator if you don't want to use Diceware.

The Diceware word list is included as a SQLite database, so no network connectivity is required. (If you don't trust this version, you can regenerate the database from the live official wordlist by using utility functions inside diceware.)

Examples

>>> from pypass.passphrase import PassphraseGenerator, transform

>>> generator = PassphraseGenerator(elements=5, separator='',
...                                 word_transform=transform.capitalize(),
...                                 phrase_transform=transform.add_numbers(2))
>>> generator.generate()
u'BeKneadJigBooneHansel29'

In the above, 5 words (elements=5) are generated using the default Diceware generator. No separator is placed between the words, but each word is passed to a transform function that capitalizes its first letter. Finally, the phrase is passed to a transform that adds two random digits to the end.

Transforms

The pypass.passphrase.transform module provides several functions that return callable transformation functions suitable for word_transform and phrase_transform. These are:

• transform.add_numbers(count) - returns a transform that adds count random digits to the end of the word/phrase

  Examples:

  # add 3 random digits to the end each word generated
  generator = PassphraseGenerator(word_transform=transform.add_numbers(3))
  
  # add 2 random digits to the end of the generated phrase
  generator = PassphraseGenerator(phrase_transform=transform.add_numbers(2))
  

• transform.capitalize() - returns a transform that will capitalize the first letter of the word/phrase

  Examples:

  # capitalize the first letter of each word generated
  generator = PassphraseGenerator(word_transform=transform.capitalize()
  

• transform.leet(probability=0.2) - returns a transform that will perform 'l33t-sp34k' transforms to the word/phrase. The probablilty that a subtitutable letter will be substituted is configurable, default is 0.2 (20%). This transform is incomplete and should be considered "pre-release".

  Examples:

  # leet transform the phrase with a 20% chance of substituting each letter
  generator = PassphraseGenerator(phrase_transform=transform.leet())
  
  # leet transform the phrase with a 50% chance of substituting each letter
  generator = PassphraseGenerator(phrase_transform=transform.leet(probability=0.5))
  

• transform.chain(...) - returns a transform that will perform the supplied list of transforms, in order, to the word/phrase.

  Examples:

  # Capitalize words, then add 2 random digits to the end of each
  generator = PassphraseGenerator(word_transform=transform.chain(transform.capitalize(),
                                                                 transform.add_numbers(2)))
  

You can also easily write your own transform function. A transform function accepts a single string argument and returns the transformed string.

Example:

def all_uppercase(word):
    return word.upper()

generator = PassphraseGenerator(word_transform=all_uppercase)

Generators

You can supply a generator object to PassphraseGenerator to use in place of the default Diceware generator. At this time, all that's required for a generator object to work properly is for it to have a method random() that meets the following design contract:

• random() with no arguments should return a single element (e.g. word)
• random(int) should:
  • if int < 1, raise ValueError
  • if int == 1, return a single element (word) as a string
  • if int > 1, return that number of elements as a list of strings

Note: you must make your own guarantees about sufficient randomness/security; pypass doesn't enforce anything. If you want secure passphrases/passwords, you should use the included generators.

See the MockGenerator class in test_passphraseGenerator.py for a simple and very insecure generator.

Future

Features I know I would like to add:

• Reliable and pessimistic password/passphrase strength estimation (as bits of entropy)
• An English Words generator (or several) to generate non-diceware passwords