pwgen/pwgen.py

#!/usr/bin/python

"""generate word compound passwords 

usage: pwgen [-c] [len default=20]
	-c   use conjunction
"""
import random, sys

target = 20		# default pw len
use_conjunction = False

n = 1
if len(sys.argv)>1 and sys.argv[1]=="-c":
	use_conjunction = True
	n = 2
if len(sys.argv)>n:
	target_arg = sys.argv[n]	# if a len is spec'd on the cmd line
	try:
		target_arg = int(target_arg)
	except:
		print "sorry, you need to give me a number"
		sys.exit()
	if target_arg<12 or target_arg>40:
		print "sorry, can't do that length"
		sys.exit()
	target = target_arg

f = open("/usr/share/dict/words")
d = f.readlines()
f.close()

num = len(d)	

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

punc = " !@#$%^&*()-_=+[{]}\|;:/?.>,<`~"
this_punc = 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 use_conjunction == False:
	if whole >= target-6:	# if 2 words is enough
		r = target-whole
		pw = w[0] + this_punc*r + w[1]
	else:		# otherwise use 3
		whole = whole + len(w[2])
		r = target-whole
		pw = w[0] + this_punc*int(r/2) + w[1] + this_punc*int(r/2) + w[2]
else:
	pw = w[0] + conjunctions[random.randint(0,len(conjunctions)-1)] + w[1]
	
print "pass phrase: "+pw