2fa.py

import base64
import hashlib
import hmac
import struct
import sys
import time


def get_hotp_token(secret, intervals_no):
    key = base64.b32decode(secret, True)
    msg = struct.pack(">Q", intervals_no)
    h = hmac.new(key, msg, hashlib.sha1).digest()
    o = ord(h[19]) & 15
    h = (struct.unpack(">I", h[o:o+4])[0] & 0x7fffffff) % 1000000
    return h


def get_totp_token(secret):
    return get_hotp_token(secret, intervals_no=int(time.time())//30)


secret = sys.argv[1]
token = str(get_totp_token(secret))
diff = 6 - len(token)
print ("0" * diff) + token