aes256 암호화 복호화

#-*-coding:utf-8-*-
import hashlib
import base64
#from Crypto import Random
from Crypto.Cipher import AES
iv = ""
BS = AES.block_size
class AESCipher:
	def __init__(self, key, ivIn):
#		print "key : " + key
#		print "iv : " + ivIn	
		self.key = hashlib.sha256(key).digest()
		global iv
		iv = ivIn
	def encrypt(self, raw):
		raw = self.on_pad(raw)
		cipher = AES.new(self.key, AES.MODE_CBC, iv)
		return base64.b64encode(iv + cipher.encrypt(raw))
	def decrypt(self, enc):
		enc = base64.b64decode(enc)
		dIv = enc[:BS]
		cipher = AES.new(self.key, AES.MODE_CBC, dIv)
	def on_pad(self, s):
		return s + (BS - len(s) % BS) * chr(BS - len(s) % BS)
	def on_unpad(self, s):
		return s[:-ord(s[len(s)-1:])]

https://stackoverflow.com/questions/12524994/encrypt-decrypt-using-pycrypto-aes-256