Select easy to use passphrases based on the diceware list; but not their selection methodology [lazy]

diceware.py

#!/usr/bin/env python
"""
Select easy to use passphrases based on the diceware list; but not their selection methodology [lazy].
Place the diceware and beale wordlists (GPG signed is fine) in /usr/share/dict before use.

* Diceware list: http://world.std.com/~reinhold/diceware.wordlist.asc
* Alternative Beale list: http://world.std.com/~reinhold/beale.wordlist.asc
* EFF List (Large): https://www.eff.org/files/2016/07/18/eff_large_wordlist.txt
* EFF List (Small): https://www.eff.org/files/2016/09/08/eff_short_wordlist_1.txt

Copyleft 2015 Ian Gallagher <[email protected]>
"""
import sys, os, random

list_file = "/Users/igallagher/Library/crash/{list_name}.wordlist.asc"
supported_lists = [
        'diceware',
        'beale',
        'eff_large',
        'eff_short'
    ]

def main():
    import optparse
    parser = optparse.OptionParser(usage="Usage: %prog [-l] [-u <list>] [-n] <num_words>")

    parser.add_option('-n', '--num_words', dest='num_words', type='int',
                      default=6, help='Number of words in passphrase (default 6) - ' \
                              'takes precedence over positional argument')
    parser.add_option('-l', '--list', dest='list', type='string',
                      default='diceware', help='List to use (diceware, beale, eff)')
    parser.add_option('-u', '--unique', dest='unique', action='store_true',
                      help='Guarantee unique words (no repeats)')

    (options, args) = parser.parse_args()

    if(6 == options.num_words and len(args) > 0 and args[0].isdigit()):
        # -n probably not specified, use positional argument for num_words
        options.num_words = int(args[0])

    if(0 >= options.num_words):
        print >> sys.stderr, "Number of words must be greater than 0."
        return(1)

    if(options.list not in supported_lists):
        print >> sys.stderr, "Unsupported list type ({bad_list}) specified, currently only the following lists are " \
                             "supported: {lists}".format(bad_list=options.list, lists=', '.join(supported_lists))
        return(1)

    num_words = options.num_words
    diceware_words = list()
    random_passwords = list()

    with open(list_file.format(list_name=options.list), 'r') as fh:
        for line in fh:
            line = line.strip()
            if(line[:5].isdigit()):
                diceware_words.append(line.split('\t', 1)[-1])

    for i in range(num_words):
        if(options.unique):
            try:
                rand_word = diceware_words.pop(random.randint(0, len(diceware_words) - 1))
                random_passwords.append(rand_word)
            except ValueError as ex:
                print "Ran out of possible values to pull from, try again with a lower number of words specified."
                sys.exit(1)
        else:
            rand_word = random.choice(diceware_words)
            random_passwords.append(rand_word)

    print ' '.join(random_passwords)

    return(0)

if '__main__' == __name__:
    sys.exit(main())

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