pwgen/pwgen.py

#!/usr/bin/python

"""generate word compound passwords 

usage: pwgen -c [number_of_phrases default=1]
or     pwgen [len default=20] [number_of_phrases default=1]    // no conjunctions
	-c   use conjunction
"""
import random, sys

targetLen = 20		# default pw len
useConjunction = False
number = 1

def toInt(s, chkRange, errStr = "sorry, that's not a number", rangeStr = "sorry, I can't do that number"):
	try:
		t = int(s)
	except:
		print errStr
		sys.exit()
	if t<chkRange[0] or t>chkRange[1]:
		print rangeStr
		sys.exit()
	return t

if len(sys.argv)>1:
	if sys.argv[1]=="-h" or sys.argv[1]=="--help":
		print "pwgen.py  v1.0  generate passphrase; inspired by xkcd/936 and SteveGibson\n"
		print "Usage: pwgen.py [length [num_phrases]] "
		print "       pwgen.py -c [num_phrases]"
		print "       pwgen.py -h | --help \n"
		print "     length       make pass phrases padded with punctuation filler; default=20"
		print "     -c           make 2 word pass phrases with a conjuction filler"
		print "     num_phrases  make multiple pass phrases, one per line; default=1\n"
		sys.exit()
	if sys.argv[1]=="-c":	# conjunction mode
		useConjunction = True
	else:				# the next number is the length
		targetLen = toInt(sys.argv[1],[12,36],rangeStr = "Sorry, I can't build phrases that long")
	if len(sys.argv)>2:
		number = toInt(sys.argv[2],[0,40])  # pick off the number of phrases
 
f = open("/usr/share/dict/words")
d = f.readlines()
f.close()

numWords = len(d)	

for i in range(number):

	w=['','','']
	for i in range(3):
		w[i] = d[random.randint(0,numWords-1)][:-1]  # toss out trailing \n
		while len(w[i]) > 10:
			w[i] = d[random.randint(0,numWords-1)][:-1]	# toss out long words
			
	whole = len(w[0])+len(w[1])

	punc = " !@#$%^&*()-_=+[{]}\|;:/?.>,<`~"
	thisPunct = punc[int(random.random() * len(punc))] 

	conjunctions = ["and", "and a", "and the","or", "or the", "or a", 
		"with a", "with", "with the", "by a", "by the", 
		"on a", "on the","on", "in a", "in the", "in", 
		"for", "for a", "for the"]

	if useConjunction == False:
		if whole >= targetLen - 6:	# if 2 words is enough
			r = targetLen - whole
			pw = w[0] + thisPunct*r + w[1]
		else:		# otherwise use 3
			whole = whole + len(w[2])
			r = targetLen - whole
			pw = w[0] + thisPunct*int(r/2) + w[1] + thisPunct*int(r/2) + w[2]
	else:
		conj = conjunctions[random.randint(0,len(conjunctions)-1)]
		if w[1][0].lower() in ['a','A','e','E','i','I','o','O','u','U']:
			if conj[-2:]==" a":
				conj = conj+'n'
		pw = w[0] + ' ' + conj + ' ' + w[1]
		
	print pw