#!/usr/bin/env python
# -*- coding:utf-8 -*-
#@author: rui.xu
#这里使用pycrypto‎库
#按照方法:easy_install pycrypto‎

from Crypto.Cipher import AES
from binascii import b2a_hex, a2b_hex
from django.conf import settings


class prpcrypt():
  def __init__(self,key):
    self.key = key
    self.mode = AES.MODE_CBC

  #加密函数，如果text不足16位就用空格补足为16位，
  #如果大于16当时不是16的倍数，那就补足为16的倍数。
  def encrypt(self,text):
    cryptor = AES.new(self.key,self.mode, b'0000000000000000')
    #这里密钥key 长度必须为16（AES-128）,
    #24（AES-192）,或者32 （AES-256）Bytes 长度
    #目前AES-128 足够目前使用
    # nonce = cryptor.nonce
    length = 32
    count = len(text)
    if count < length:
      add = (length-count)
      #\0 backspace
      text = text + ('\0' * add)
    elif count > length:
      add = (length-(count % length))
      text = text + ('\0' * add)
    print(text)
    self.ciphertext = cryptor.encrypt(text.encode("utf8"))
    #因为AES加密时候得到的字符串不一定是ascii字符集的，输出到终端或者保存时候可能存在问题
    #所以这里统一把加密后的字符串转化为16进制字符串
    return b2a_hex(self.ciphertext)

  #解密后，去掉补足的空格用strip() 去掉
  def decrypt(self,text):
    cryptor = AES.new(self.key,self.mode,b'0000000000000000')
    plain_text  = cryptor.decrypt(a2b_hex(text)).decode("utf8")
    return plain_text.rstrip('\0')

pc = prpcrypt(settings.CRYPT_KEY.encode('utf8')) #初始化密钥

if __name__ == '__main__':
  # for test
  print(settings.CRYPT_KEY)
  pc = prpcrypt(settings.CRYPT_KEY.encode('utf8')) #初始化密钥
  import sys
  str = sys.argv[1]
  e = pc.encrypt(str) #加密
  print("加密:",e)
  d = pc.decrypt(e) #解密
  print("解密:",d)