xkcdpass

A flexible and scriptable password generator which generates strong passphrases, inspired by XKCD 936:

$ xkcdpass
> correct horse battery staple

Install

xkcdpass can be easily installed using pip:

pip install xkcdpass

or manually:

python setup.py install

Source

The latest development version can be found on github: https://github.com/redacted/XKCD-password-generator

Contributions welcome and gratefully appreciated!

Requirements

Python 2 (version 2.7 or later), or Python 3 (version 3.2 or later).

Running xkcdpass

xkcdpass can be called with no arguments:

$ xkcdpass
> pinball previous deprive militancy bereaved numeric

which returns a single password, using the default dictionary and default settings. Or you can mix whatever arguments you want:

$ xkcdpass --count=5 --acrostic='chaos' --delimiter='|' --min=5 --max=6 --valid-chars='[a-z]'
> collar|highly|asset|ovoid|sultan
> caper|hangup|addle|oboist|scroll
> couple|honcho|abbot|obtain|simple
> cutler|hotly|aortae|outset|stool
> cradle|helot|axial|ordure|shale

which returns

• --count=5 5 passwords to choose from
• --acrostic='chaos' the first letters of which spell 'chaos'
• --delimiter='|' joined using '|'
• --min=5 --max=6 with words between 5 and 6 characters long
• --valid-chars='[a-z]' using only lower-case letters (via regex).

A concise overview of the available xkcdpass options can be accessed via:

xkcdpass --help

Usage: xkcdpass [options]

Options:
    -h, --help
                                show this help message and exit
    -w WORDFILE, --wordfile=WORDFILE
                                Specify that the file WORDFILE contains the list of
                                valid words from which to generate passphrases.
                                Provided wordfiles: eff-long (default), eff-short,
                                eff-special, legacy
    --min=MIN_LENGTH
                                Minimum length of words to make password
    --max=MAX_LENGTH
                                Maximum length of words to make password
    -n NUMWORDS, --numwords=NUMWORDS
                                Number of words to make password
    -i, --interactive
                                Interactively select a password
    -v VALID_CHARS, --valid-chars=VALID_CHARS
                                Valid chars, using regexp style (e.g. '[a-z]')
    -V, --verbose
                                Report various metrics for given options, including word list entropy
    -a ACROSTIC, --acrostic=ACROSTIC
                                Acrostic to constrain word choices
    -c COUNT, --count=COUNT
                                number of passwords to generate
    -d DELIM, --delimiter=DELIM
                                separator character between words

Word lists

Several word lists are provided with the package. The default, eff-long, was specifically designed by the EFF for passphrase generation and is licensed under CC BY 3.0. As it was originally intended for use with Diceware ensure that the number of words in your passphrase is at least six when using it. Two shorter variants of that list, eff-short and eff-special, are also included. Please refer to the EFF documentation linked above for more information.

The original word list from xkcdpass versions earlier than 1.10.0 is also provided as a convenience, and is available under legacy. This word list is derived mechanically from 12Dicts by Alan Beale. It is the understanding of the author of xkcdpass that purely mechanical transformation does not imbue copyright in the resulting work. The documentation for the 12Dicts project at http://wordlist.aspell.net/12dicts/ contains the following dedication:

The 12dicts lists were compiled by Alan Beale. I explicitly release them to the public domain, but request acknowledgment of their use.

Note that the generator can be used with any word file of the correct format: a file containing one 'word' per line.

Using xkcdpass as an imported module

The built-in functionality of xkcdpass can be extended by importing the module into python scripts. An example of this usage is provided in example_import.py, which randomly capitalises the letters in a generated password. example_json.py demonstrates integration of xkcdpass into a Django project, generating password suggestions as JSON to be consumed by a Javascript front-end.

A simple use of import:

from xkcdpass import xkcd_password as xp

# create a wordlist from the default wordfile
# use words between 5 and 8 letters long
wordfile = xp.locate_wordfile()
mywords = xp.generate_wordlist(wordfile=wordfile, min_length=5, max_length=8)

# create a password with the acrostic "face"
print(xp.generate_xkcdpassword(mywords, acrostic="face"))

When used as an imported module, generate_wordlist() takes the following args (defaults shown):

wordfile=None,
min_length=5,
max_length=9,
valid_chars='.'

While generate_xkcdpassword() takes:

wordlist,
numwords=6,
interactive=False,
acrostic=False,
delimiter=" "

Insecure random number generators

xkcdpass uses crytographically strong random number generators where possible (provided by random.SystemRandom() on most modern operating systems). From version 1.7.0 falling back to an insecure RNG must be explicitly enabled, either by using a new command line variable before running the script:

xkcdpass --allow-weak-rng

or setting the appropriate environment variable:

export XKCDPASS_ALLOW_WEAKRNG=1

Changelog

• 1.11.1 Fix bug in entropy calc
• 1.11.0 Rewrite verbose report to take acrostics etc into account
• 1.10.0 Switch to EFF wordlist as default (note: decrease in entropy of default length passwords to 77 bits, still at EFF recommendations)
• 1.9.5 Fix broken test
• 1.9.4 Improve office-safe wordlist contents
• 1.9.3 Link EFF wordlist information, fix typos, update copyright
• 1.9.2 Added Debian cracklib path
• 1.9.1 Fixed typo in example
• 1.9.0 Improvements to interactive mode
• 1.8.2 generate_wordlist behaviour didn't match docstring, fixed
• 1.8.1 Fix typo in validation function
• 1.8.0 Fix error in wordfile argument handling

License

This is free software: you may copy, modify, and/or distribute this work under the terms of the BSD 3-Clause license. See the file LICENSE.BSD for details.