Random Password Generation

First implementation: 14 character long with 6 letters and 8 digits

#!/usr/bin/env python3

# file: passgen-v1.py

import random

LETTERS = "abcdefghijklmnopqrstuvwxyz"

if __name__ == "__main__":

passwd = []

for i in range(6):

passwd.append(random.choice(LETTERS))

for i in range(8):

passwd.append(random.choice("1234567890"))

print("".join(passwd))

The passwords that come out of this are a bit difficult to type so I forced it to alternate between the left and right hands

#!/usr/bin/env python3

# file: passgen-v2.py

import random

LEFTS = "',.pyaoeui;qjkx"

RIGHTS = "fgcrldhdhtns-bmwvz"

if __name__ == "__main__":

passwd = []

for i in range(6):

if i % 2 == 0:

passwd.append(random.choice(LEFTS))

else:

passwd.append(random.choice(RIGHTS))

for i in range(8):

if i % 2 == 0:

passwd.append(random.choice("123456"))

else:

passwd.append(random.choice("7890"))

print("".join(passwd))

The regularity of switching between left and right hands (intuitively, and almost surely) decreases the entropy of the password, so use markov models to make that happen for the most part but critically NOT enforce it.

#!/usr/bin/env python3

# file: passgen-v3.py

import random

Ls = [

"aoeui", # L1

"',.py", # L2

";qjkx", # L3

"123456", # L4

"-snthd", # R1

"lrcgf", # R2

"zvwmb", # R3

"7890" # R4

]

A = [[ .03, .03, .03, .01, .27, .27, .27, .09],

[ .03, .03, .03, .01, .27, .27, .27, .09],

[ .03, .03, .03, .01, .27, .27, .27, .09],

[.004, .003, .003, .09, .03, .03, .03, .81],

[ .27, .27, .27, .09, .03, .03, .03, .01],

[ .27, .27, .27, .09, .03, .03, .03, .01],

[ .27, .27, .27, .09, .03, .03, .03, .01],

[ .03, .03, .03, .81, .004, .003, .003, .09]]

pi = [ .41, .03, .03, .03, .41, .03, .03, .03]

def sample( l ):

l_partial = [ sum(l[:i+1],0) for i in range(len(l))]

u = random.uniform(0,1)

for j,v in enumerate(l_partial):

if v > u:

return j

if __name__ == "__main__":

passwd = []

s = sample(pi)

for i in range(20):

s = sample(A[s])

passwd.append(random.choice(Ls[s]))

print("".join(passwd))

For increased entropy should also consider peppering in a few upper case characters.

#!/usr/bin/env python3

# file: passgen-v3.py

import random

Ls = [

"aoeui", # L1

"',.py", # L2

";qjkx", # L3

"123456", # L4

"-snthd", # R1

"lrcgf", # R2

"zvwmb", # R3

"7890" # R4

]

A = [[ .03, .03, .03, .01, .27, .27, .27, .09],

[ .03, .03, .03, .01, .27, .27, .27, .09],

[ .03, .03, .03, .01, .27, .27, .27, .09],

[.004, .003, .003, .09, .03, .03, .03, .81],

[ .27, .27, .27, .09, .03, .03, .03, .01],

[ .27, .27, .27, .09, .03, .03, .03, .01],

[ .27, .27, .27, .09, .03, .03, .03, .01],

[ .03, .03, .03, .81, .004, .003, .003, .09]]

pi = [ .41, .03, .03, .03, .41, .03, .03, .03]

UPPER=.1

def sample( l ):

l_partial = [ sum(l[:i+1],0) for i in range(len(l))]

u = random.uniform(0,1)

for j,v in enumerate(l_partial):

if v > u:

return j

if __name__ == "__main__":

passwd = []

s = sample(pi)

for i in range(20):