Pwmodels

Password research often requires modelling password distributions from a password leak. (I have to rewrite similar code for at least four times for different projects.) Hence, this module!

In this module I plan to add different password models, such as n-gram and PCFG. In current version it supports,

• n-gram or Markovian password model
• Weir et al. PCFG, and
• simple histogram of the passwords.

Install

$ pip install git+https://github.com/rchatterjee/pwmodels.git

Usage

from pwmodel import NGramPw, PcfgPw, HistPw
pwm = NGramPw(pwfilename='/Users/badger/passwords/myspace-withcount.tar.bz2', n=4)
print pwm.prob('passwords123')

See tests/ for more usage information.

Version

1.3

TODO

• Add a function to enable the models to churn out passwords in decreasing order of their probability
• Add better pcfg model, especially updated with keyboard sequence, and repeating characters, more natural way of spliting the password than just based on continuous sequence of letters, digits and symbols.
• n-gram model is pretty slow now, because it has to comppute the sum of frequency of all the passwords that start with START (which is a lot).

Changelog

1. Added readpw.py, ann utility to read password leak data.