SecureCRT logon script for google authenticator.

logon-py3.py

# $language = "python"
# $interface = "1.0"

import base64
import hmac
import struct
import sys
import time

TOTP_KEY = 'YOUR_GOOGLE_AUTH_KEY'

def hotp(key, counter, digits=6, digest='sha1'):
  key = base64.b32decode(key.upper() + '=' * ((8 - len(key)) % 8))
  counter = struct.pack('>Q', counter)
  mac = hmac.new(key, counter, digest).digest()
  offset = mac[-1] & 0x0f
  binary = struct.unpack('>L', mac[offset:offset+4])[0] & 0x7fffffff
  return str(binary)[-digits:].zfill(digits)

def totp(key, time_step=30, digits=6, digest='sha1'):
  return hotp(key, int(time.time() / time_step), digits, digest)

def main():
  tab = crt.GetScriptTab()

  if tab.Session.Connected != True:
    crt.Dialog.MessageBox("Session Not Connected")
    return

  tab.Screen.Synchronous = True
  tab.Screen.WaitForStrings('Verification code:')
  vc = totp(TOTP_KEY)
  tab.Screen.Send("{vc}\r".format(vc=vc))
  return

main()

logon.py

import hmac, base64, struct, hashlib, time, json, os

TOTP_KEY = 'YOUR_GOOGLE_AUTH_KEY'

def get_hotp_token(secret, intervals_no):
  """This is where the magic happens."""
  key = base64.b32decode(normalize(secret), True) # True is to fold lower into uppercase
  msg = struct.pack(">Q", intervals_no)
  h = hmac.new(key, msg, hashlib.sha1).digest()
  o = ord(h[19]) & 15
  h = str((struct.unpack(">I", h[o:o+4])[0] & 0x7fffffff) % 1000000)
  return prefix0(h)


def get_totp_token(secret):
  """The TOTP token is just a HOTP token seeded with every 30 seconds."""
  return get_hotp_token(secret, intervals_no=int(time.time())//30)


def normalize(key):
  """Normalizes secret by removing spaces and padding with = to a multiple of 8"""
  k2 = key.strip().replace(' ','')
  # k2 = k2.upper()  # skipped b/c b32decode has a foldcase argument
  if len(k2)%8 != 0:
    k2 += '='*(8-len(k2)%8)
  return k2


def prefix0(h):
  """Prefixes code with leading zeros if missing."""
  if len(h) < 6:
    h = '0'*(6-len(h)) + h
  return h


def main():
  tab = crt.GetScriptTab()

  if tab.Session.Connected != True:
    crt.Dialog.MessageBox("Session Not Connected")
    return

  tab.Screen.Synchronous = True
  tab.Screen.WaitForStrings(['Verification code:'])
  vc = get_totp_token(TOTP_KEY)
  tab.Screen.Send("{vc}\r".format(vc=vc))
  return

main()