Update libs

2013-11-22 16:09:15 +01:00
parent f53364eb6c
commit 88d6148500
119 changed files with 18448 additions and 8923 deletions
@@ -0,0 +1,71 @@
+#!/usr/bin/env python
+# -*- coding: utf-8 -*-
+
+import argparse, math, random
+
+from pyutil.mathutil import div_ceil
+
+from pkg_resources import resource_stream
+
+def recursive_subset_sum(entropy_needed, wordlists):
+    # Pick a minimalish set of numbers which sum to at least
+    # entropy_needed.
+
+    # Okay now what's the smallest number of words which will give us
+    # at least this much entropy?
+    entropy_of_biggest_wordlist = wordlists[-1][0]
+    assert isinstance(entropy_of_biggest_wordlist, float), wordlists[-1]
+    needed_words = div_ceil(entropy_needed, entropy_of_biggest_wordlist)
+    # How much entropy do we need from each word?
+    needed_entropy_per_word = entropy_needed / needed_words
+    # What's the smallest wordlist that offers at least this much
+    # entropy per word?
+    for (wlentropy, wl) in wordlists:
+        if wlentropy >= needed_entropy_per_word:
+            break
+    assert wlentropy >= needed_entropy_per_word, (wlentropy, needed_entropy_per_word)
+
+    result = [(wlentropy, wl)]
+    # If we need more, recurse...
+    if wlentropy < entropy_needed:
+        rest = recursive_subset_sum(entropy_needed - wlentropy, wordlists)
+        result.extend(rest)
+    return result
+
+def gen_passphrase(entropy, allwords):
+    maxlenwords = []
+    i = 2 # The smallest set is words of length 1 or 2.
+    words = [x for x in allwords if len(x) <= i]
+    maxlenwords.append((math.log(len(words), 2), words))
+    while len(maxlenwords[-1][1]) < len(allwords):
+        i += 1
+        words = [x for x in allwords if len(x) <= i]
+        maxlenwords.append((math.log(len(words), 2), words))
+
+    sr = random.SystemRandom()
+    passphrase = []
+
+    wordlists_to_use = recursive_subset_sum(entropy, maxlenwords)
+
+    passphraseentropy = 0.0
+    for (wle, wl) in wordlists_to_use:
+        passphrase.append(sr.choice(wl))
+        passphraseentropy += wle
+            
+    return (u".".join(passphrase), passphraseentropy)
+
+def main():
+    parser = argparse.ArgumentParser(prog="chbs", description="Create a random passphrase by picking a few random words.")
+
+    parser.add_argument('-d', '--dictionary', help="what file to read a list of words from (or omit this option to use chbs's bundled dictionary)", type=argparse.FileType('rU'), metavar="DICT")
+    parser.add_argument('bits', help="how many bits of entropy minimum", type=float, metavar="BITS")
+    args = parser.parse_args()
+
+    dicti = args.dictionary
+    if not dicti:
+        dicti = resource_stream('pyutil', 'data/wordlist.txt')
+    allwords = set([x.decode('utf-8').strip().lower() for x in dicti.readlines()])
+
+    passphrase, bits = gen_passphrase(args.bits, allwords)
+
+    print u"Your new password is: '%s'. It is worth about %s bits." % (passphrase, bits)