I was updating a random password generator for a project, thought I'd share the resulting code. Also availabe as a gist.

Using a default length of 14 characters this should generate passwords with 84 bits of entropy.

#!/usr/bin/env python
# -*- coding: utf-8 -*-

import os, string

def random_password(length=14):
    """
    Random password generator.

    Default generated password will have an entropy of 84 bits.

    For each character in the password, generate a random byte, reduce
    the integer value to modulo 64 and use the result as an index on
    the character pool.

    In a 64 character pool, each character will have an entropy of 6
    bits. With a lenght of 14 characters the total entropy is 84 bits:

        log2(64) * 14 = 84 bits

    The difference between 13 and 14 characters can be several years
    to brute force. """

    characters = string.ascii_letters + string.digits + '+/'

    l = list()
    for x in xrange(length):
        i = ord(os.urandom(1)) % len(characters)
        c = characters[i]
        l.append(c)
    return ''.join(l)

if __name__ == '__main__':
    print(random_password())

Generating passwords is easy, storing them safely seems to be more of a challenge.