#!/usr/bin/env python

# -*- coding:utf-8 -*-

import hmac, base64, struct, hashlib, time

def calGoogleCode(secretKey):

    """

    :param secretKey: 16个字符

    :return:

    """

    input_time = int(time.time())//30

    key = base64.b32decode(secretKey)

    msg = struct.pack(">Q", input_time)

    googleCode = hmac.new(key, msg, hashlib.sha1).digest()

    o = ord(str(googleCode)[19]) & 15

    googleCode = str((struct.unpack(">I", googleCode[o:o+4])[0] & 0x7fffffff) % 1000000)

    if len(googleCode) == 5:             # 如果验证码的第一位是0，则不会显示。此处判断若是5位码，则在第一位补上0

        googleCode = '' + googleCode

    return googleCode

print(calGoogleCode('EKPHIPYDEN7RAAAB'))