wordpassword_reordering.py

#!/usr/bin/env python

import random
random = random.SystemRandom()

dictionary = open('/usr/share/dict/words', 'r').read().split()

dictionary = [w.lower() for w in dictionary if len(w) < 10]

# reasoning for these parameters:
# http://www.wolframalpha.com/input/?i=%28%28119%2C000+**+5+*+500+**+3%29+%2F+%287%21+*+50%29%29+**+%281%2F18%29+%3E+36
# ((119,000 ** 5 * 500 ** 3) / (7! * 50)) ** (1/18) > 36
# 500 is the estimated number of stopwords in common use

assert len(set(dictionary)) > 119000, "dictionary too small!"
equiv_passwordbase = 36
equiv_passwordlen = 18
chooseyness = 50
offered_word_count = 7
complex_word_count = 5
stopword_count = 3
practice_amount = 15

def check(acceptable, phrase_words):
    return (
        len([w for w in phrase_words if w in acceptable]) >= complex_word_count
        and len(acceptable.split()) >= stopword_count + complex_word_count)

print "variations must contain spaces between words,"
print "and must use at least", complex_word_count,
print "of the", offered_word_count ,"offered words."
print "variations must contain at least", stopword_count,
print "of your own custom-chosen stopwords (trivial words like 'the', 'of', etc.)."

for x in xrange(chooseyness):
    phrase_words = [random.choice(dictionary) for y in xrange(offered_word_count)]
    phrase = ' '.join(phrase_words)
    acceptable = raw_input("is %r acceptable? type a variation: " % phrase)
    if not check(acceptable, phrase_words):
        print "missing (a )word(s), skipping"
        continue
    else:
        for z in range(15):
            v = raw_input("retype variation: ").lower()
            if not check(acceptable, phrase_words):
                print "missing (a )word(s), skipping"
                break
        else:
            print
            print "    kay, use that password. no more will be offered."
            print
            break
else:
    print
    print
    print "    WARNING: DO NOT RERUN THIS PROGRAM FOR THIS PASSPHASE CHOICE."
    print "       CHOOSE ONLY FROM ABOVE OPTIONS. YOU ARE BEING TOO CHOOSEY."
    print
    print